World Electr. Veh. J., Volume 4, Issue 3 (September 2010) – 32 articles , Pages 437-670

This paper proposes a novel hybridized vehicle inter-dependent control transmission architecture (VICTA) that offers key advantages over existing systems. It embodies a compact torque generation system formed by two or more electric machines axially linked through a conventional mechanical differential gear assembly by means of a simple yet innovative pair of co-axial shafts. The resultant electric-mechanical hybridized drivetrain system allows a unique and automatic way of transmitting, differentially and inter-dependently, the electromagnetic torques generated by the motors at either side of differential gear. A realistic virtual prototype of the VICTA based on MATLAB/Simulink modules is developed to validate the concept. Comprehensive performance prediction tests, including steering maneuvering and variations of the road surface, are undertaken. Excellent simulation results from the VICTA virtual prototype demonstrate its stability and motility performance. The results also confirm the VICTA concept has key advantages such as reliability, modularity, high efficiency and simplicity, and yet does not inherit the undesirable features of high unsprung mass or complex software control that continue to challenge and even flaw the existing systems. Full article

Typical automotive trips are within the driving range of efficient electric vehicles (EVs), but sometimes exceeding EV range is needed for occasional trips. This paper proposed a new kind of range extended electric vehicle. A mobile generator set is used as a range extender, when assembled in an EV, effectively converts the EV to series-hybrid mode for long trips. The new kind of range extended EV, which integrates the charger, rectifier and DC/DC into a charger, is more suitable for use in low-speed micro EVs than Plugin Electric Vehicle (PHEV) and a Range Extender Trailer (RXT) system. The fuel economy and main performance criteria of the new range extended EV are shown in this paper. In some drive cycles, the new range extended EV has a better fuel economy than PHEV and RXT system. Full article

The interior permanent magnet synchronous motor (PMSM) can offer many advantages, including high power-to-weight ratio, high efficiency, rugged construction, low cogging torque and the capability of reluctance torque, so it is widely used in electric vehicle (EV). Two control schemes, namely field oriented control (FOC) and direct torque control (DTC) are used in PMSM drive. In order to decrease current and torque ripple and fix switching frequency, an improved DTC scheme based on the control of stator flux, torque angle and torque was proposed, which used voltage vector selection strategy and the technology of space vector modulation (SVM) to generate the applied voltage vector instead of switching table. And this paper compared these three control schemes based on a 15-kW interior PMSM used in Honda Civic 06My hybrid electrical vehicle. Experimental results show for the FOC using the hysteresis current control, due to the lower sampling period, stator current is more sinusoidal. But it needs the continuous rotor position information and the switching frequency of the VSI is not constant. For the DTC using switching table, current ripple is higher and the switching frequency of the VSI is also not constant. But it does not need the rotor position information except for the initial rotor position. Compared with switching table, the proposed DTC can decrease current and torque ripple and fix switching frequency. Full article

Energy depletion becomes much more popular especially for petroleum decline sharply, all country on the earth try to decrease their usage of petroleum seriously. Electric vehicle (EV) technology holds much promise for reducing the demand for petroleum and reducing the emission of carbon dioxide. However, the most important issue for EV is its power supply – battery module. Therefore, we propose this architecture which is cooperate between EV network design and remote diagnostic service in order to extend the life of battery and raise the safety of EV driving. All of systems on the vehicle can communication each other and have appropriate action to raise the efficiency of battery usage through the EV network design. Otherwise, the remote diagnostic service can provide drivers the better strategy to resolve some simple problem and recharge the battery via this cooperative architecture. This architecture can increase the mass population of EV and guarantee the quality of battery to raise the utility rate. Full article

Based on the technology of conventional engine dynamic test system, using high dynamic AC frequency conversion dynamometer, developing of the simulators of road load, vehicle inertia, driver etc., a heavy duty hybrid power train dynamic test stand is developed. The stand can supply a near real road environment for hybrid power train of the vehicle. The R&D of different coupling structure of hybrid power train can be executed in the test system. All kinds of vehicle performance tests including power performance tests, energy economy tests, special hybrid function tests etc. can be implemented in it. The developed hybrid power train dynamic test system is a useful tool for developing the key technology of hybrid electric bus. Full article

With the ever rising price of oil, driven by the gradual depletion of global oil deposits, along with the serious global warming issues caused by substantial CO2 emissions, energy saving and environmental protection awareness are expanding issues of global concern. The trend of green energy industry is prevailing in the industrial design and development of vehicles. Therefore, electric vehicles focusing on low energy consumption and zero pollutant emission have become the development direction of the future, recognized in succession by various global vehicle manufacturing giants. The design methods of the Powertrain System for electric vehicles vary depending on different structures and arrangement methods of the vehicle; there are also two different practices in regard to the Drive System design. On one hand, as the powertrain characteristics of a traction motor differ from those of an engine, in order to make an electric vehicle which possesses the same performance as a traditional vehicle, it is required to match the traction motor with the transmission. On the other hand, being an electric vehicle, the number of traditional vehicle components used should be reduced, while only using a traction motor equipped with a single ratio gearbox. This study conducted an analysis on the performance discrepancy between an electric vehicle with 5-speed transmission and that with a single ratio gearbox, and compared their strengths and weaknesses by observing their performance in overcoming road loads through simulation. Full article

The parallel hybrid powertrain developed by Punch Powertrain provides also a nice solution for range extender and boosted range extender vehicles. While most range extender solutions like the GM Volt or the Jaguar XJ Limo Green Hybrid Concept have a series hybrid topology Punch‘s uses a parallel hybrid topology. A parallel topology offers a higher efficiency when the vehicle is driven in hybrid mode. This is even more the case by applying the strategy developed at Punch for this powertrain. This strategy can narrow down the combined engine and CVT operation to peak efficiency.
This parallel topology does not only offer the possibility to extend the EV-range of the vehicle, it also allows extending the power in cases the vehicle is used in high power situations its EV powertrain is not designed for. By applying this powertrain in vehicles used for urban and suburban deliveries the electric powertrain can be sized for the majority of its use, i.e. low to medium speed driving using low to medium power. The engine can kick in when more power is required, e.g. high speed driving or accelerating with high payloads.
Consequently this concept allows using a lower power rating for the electric powertrain (motor/generator and battery). Due to its parallel topology also one electric machine is required. These cost advantages come with the necessity to use a CVT transmission. Most parts of this transmission are already made in high volume while the other parts are carried over from the other hybrid powertrains from Punch. Consequently this CVT transmission can be produced at low cost.
As such Punch Powertrain offers a valid alternative to equip electric vehicles with a cost and fuel efficient range extender or boosted range extender powertrain. Full article

The IWME (Integrated Wheels of Mechanics and Electrics) includes an In-Wheel PMSM (Permanent Magnet Synchronous Motor), a reduction device, a brake device, the lubricating and cooling system, and so on in the hub of the tyre. It’s the key factor to improve the performance of EV (Eletric Vehicle) and HEV (Hybird Electric Vehicle). In this paper, The IWME will be applied to a special type vehicle and mid-heavy vehicle; its integrated composition is complex. The authors have advanced the simulation analysis method of the motorized wheel based on PMSM. By the method, the main dynamic system parameters of the IWME are analyzed and simulated forward and backward with the Matlab/Simulink models of the IWME and the vehicle, in order to adapt the vehicle and to test its dynamic response. With the FEA (Finite Element Analysis), the optimization design of the IWME has been achieved. The shell structures and supporters of major components and parts have been strengthened. By evaluating the final optimization results, integrated design level has been improved according to the design method in the paper. Copyright Form of EVS25. Full article

This paper proposed on-line parameter estimation method to compensate the magnetic cross-saturation effect on the interior permanent magnet synchronous motor (IPMSM) control system for electric vehicle. The decoupling control model for IPMSM with magnetic saturation compensation based on SVPWM (Space Vector PWM) method is established. Though comparing the simulation results between model with saturation compensation of parameter estimation and ones without saturation compensation, it is verified that the control performance with saturation compensation is more stable and more accurate than that of without compensation over speed operating region especially at higher speed. The on-line parameter estimation method based on decoupling control improves the system following-up performance, robustness and the control accuracy effectively. Full article

In order to meet the China’s PHASE III and emission Ⅳ legislations, Electronic Unit Pump (EUP) system has been used by many diesel engine companies in China. The fluctuation on small cycle fuel injection quantity (SCFIQ) has great influence on the stability at small load operation of the diesel engine. A numerical model of the EUP system was built in the AMESim environment for the purpose of computing and analyzing the fluctuation on the SCFIQ. The influence of the different parameters on small cycle fuel injection quantity fluctuation (SCFIQF) has been obtained by the AMESim simulation model. By computing and analyzing, the quantitative percentage index of the influence on SCFIQ caused by different parameters also has been obtained. The influence percentage of injector characteristic parameters is from 35.8% to 60.8%, plunger characteristic parameters is from 20.3% to 34.8%, low pressure supply fuel characteristics is from 0 to 20.2%, and valve characteristic parameters is form 6.6% to 23.2% with the revolution range from 500r/min to 1300r/min. Based on the design of experiment (DOE) method, take the without interaction and interaction into consideration, the correlations of SCFIQ and different factors have been obtained and analyzed. Copyright Form of EVS25. Full article

Generally, In-Wheel motor system consists of suspension, steering, electric motor, friction brake, and wheel and varies with the combination structure of each component. However, the key point of In-Wheel motor system to be applied in small electric vehicle is the integration capability to meet the requirements such as wheel space, power performance, strength of components and so on. This paper describes integration methodology for In-Wheel motor system on the rear axle with the consideration of the restricted wheel space and unsprung mass. In addition, optimization of the motor housing is performed to improve mass and strength of the In-Wheel motor housing according to the test specification of weight transfer from the tire patch. It is found from the results that the prototype In-Wheel motor system meets the vehicle performances and strength requirements. Full article

At last year's edition of EVS, we presented an improved model for iron losses prediction in Permanent Magnet Synchronous Machines (PMSM) [1]. The benefit of this model holds in that it fits more closely the real material behavior than the standard Steinmetz or Bertotti approaches [2], by including 1) magnetic material characteristics measured at high frequency and 2) an improved representation of iron losses at the approach to saturation (by introducing a higher order term in J). We are taking this model a step further by considering now another phenomenon impacting iron losses in electrical machines: the decrease of magnetic permeability and the increase of local hysteresis loss at the vicinity of lamination edges due to the cutting process. This paper presents a quantitative analysis of the impact of lamination processing (cutting, punching, etc) for high quality low loss electrical steels used in automotive traction applications. It is important to perform the analysis over a wide frequency range, because of the large speed range of PMSM drives in automotive applications and the presence of higher harmonics (PWM supply). Our approach consists in measuring the material characteristics for sample sets with different ratios of degraded vs. non degraded material and at various frequencies. Starting from that experimental data we propose a method to determine the local magnetization curves, as function of distance from the cut edge. These local material characteristics can then be implemented in a FE model so that the effect of punching on the machine performance can be determined quantitatively: (1) the cutting impact on magnetization modification allows more precise field calculations; (2) a proposition is made on the implementation of the cutting impact on the loss calculations in post processing via an enhanced version of the loss model developed in [1]. Full article

The paper describes four novels virtually zero-emission three-stage automotive gas turbine propulsion and/or dispulsion powertrains for parallel hybrid-electric vehicles. In these automotive gas turbines with oxy-fuel combustion (i.e., methane in a nearly pure oxygen environment), each including three turbine rotors operating upon independent shafts, one rotor is designed to drive the compressor or pump, one is designed to produce the main part of the power output and the third rotor is adapted to aid the two first mentioned rotors. Full-time and/or part-time exhaust gas recirculation introduces exhaust gas or liquid into the compressor’s air intake or the pump’s fluid inlet of the compressor or pump replacing some of the air or supercritical fluid, respectively. Full article

To satisfy the demands of electric vehicles (EVs) of fast torque response in wide range of velocity, the principle of flux weakening of the stator-doubly-fed doubly salient (SDFDS) motor which is designed for EVs has been studied and analyzed. And its advantage of regulating the field flux independently has been fully utilized. The flux weakening strategy is proposed and high performance of SDFDS motor drive is acquired at high speed. Simulation and experiment are carried out based on Matlab/Simulink and experiment platform. The simulation and experimental results with good speed adjusting performance verify the effectiveness of the flux weakening control strategy of SDFDS motor drive. Full article

This paper describes a driving torque distribution method for front–and-rear-wheel-independent-drivetype electric vehicles (FRID EVs) in which it is possible to get stable steering on a low friction coefficient road surface. This method is characterized by distributing driving torque to the left and right wheels of the front and rear wheels, considering not only load movement of the longitudinal direction but also load movement of the lateral direction which is generated at cornering. The load movements are estimated by detecting components of the 3-axis directions, i.e., longitudinal and lateral accelerations and yaw rate, and the steering angle and friction coefficient μ of the road surface. The effectiveness of the proposed driving torque distribution method was verified using simulators equivalent to the prototype FRID EV simulated with Matlab/Simulink and CarSim software. This method is expected to be indispensable to improving running performance of FRID EVs. Full article

A function modularization control system is established for the vehicle with a new full hybrid power-train structure consisting of two electric motors and a set of coupling device. Control strategies based on ICE optimized operation schedule are utilized to improve the power-train efficiency and to reduce fuel consumption. With the development tool of MATLAB/SIMULINK and special debugging tool, a prototype of multi-energy control unit is completed. Over 5,000 kilometers road test of the vehicle shows the feasibility and reliability. And the performance of the vehicle has been improved. Full article

This paper presents the new compact hybrid planetary transmission drive (CHPTD) as a solution of plug-in hybrid electric vehicle (PHEV). The presented CHPTD is more compact and lower costs than other seriesparallel hybrid drives equipped with planetary transmission and two motors. Proper architecture and elements were designed to achieve functions of PHEV. The powertrain and its components were optimized and determined by nonlinear dynamic modeling and simulations. Parameters of powertrain were adjusted and optimized by observation of simulation results. Two basic control strategies were analyzed to achieve minimum energy consumption and suitable operation range of battery state of charge. The very effective operation of the worked out powertrain was proved by tests in different driving conditions regarding city traffic and suburb area. The advantages of planetary transmission which is power summing mechanical unit, was obtained by proper design and control of innovative high energy saving electromagnetic clutch/brake device based on classic dual-diaphragm spring system. Full article

One important task of electrification of vehicle powertrain is the functional integration of all new systems in respect of the performance, comfort and emission restrictions. In this particular case, starting from a mass produced vehicle platform in the small vehicle segment, the requirement was to keep the originally installed powertrain largely unchanged, but on the other hand enabling hybrid operating functions such as boosting and recuperating and additionally providing some torque vectoring features, under all relevant driving situations. The paper describes and explains the possibilities and limitations of an electrically supported four wheel drive system: first in simulation by use of a mathematical model and then, the experiences gained in the actual development of a prototype car, will be reported. A special focus will be put on the methodology of the development of a model based hybrid controller. Full article

Technique of Step-skewing of rotor (SSR) is much efficient to reduce the harmonics of Back EMF, minimize cogging torque and torque ripple. In EV & HEV applications, it can conspicuously increase the torque control precision, decrease torque ripple, thus improve the vehicle comfort. This paper analyzed the no-load and load performance of motor with step-skewed rotor and another with slot-skewed stator. Through comparing the performance of each motor, this paper revealed the advantage of step-skew technique. The conclusion is verified by FEA and experiment. Copyright form of EVS25. Full article

In order to further improve the fuel economy of vehicles, an efficient energy regeneration system for diesel engines is designed and constructed. An additional automatic clutch is added between the engine and the motor in a conventional ISG (Integrated Starter and Generator) system. During regenerative braking, the clutch can be disengaged and the engine braking is avoided. Control strategy is redesigned to determine the braking torque distribution and coordinate all the components. The generated electricity is increased and the fuel economy is improved. An experiment is designed to test the performance of the new energy regeneration system, and the result shows that during a regenerative braking test over 112% more electric energy can be regenerated without correcting for the fuel consumption at idle. Theoretical analysis also shows that the regenerated energy would be increased at least 63.1% for a single regenerative braking event with the new system, if we correct for the fuel consumption at idle. Full article

All electric-damper is now a fashionable method for vehicle balance as the development of the high power linear and motor drive system allow the fast and efficient solution to dampers. The conventional damper is then replaced by active motor drive that provides faster response than the conventional system. In this paper, an LMFC method is proposed to provide a better control method for the four dampers that is located in the vehicle. The 4-coordinate control is difficult as they are closely related to each other. The heave position, pitch and roll angle are the main concerns to keep consistent for the passenger’s comfort and ride performance. To achieve this goal, an effective LMCF is investigated and applied to the active damper system, with its simplicity and reliable for implementation. For the active damper system, the inner loop is with PD control to eliminate the disturbances and nonlinearities, while the outer loop is with linear model following control to track the required dynamic performance. The computed results verify the proposed control methods, and the dynamic response of the active damper systems is studied by optimization Full article

EVO Electric has designed, built and tested the DuoDrive hybrid system based on proprietary axial flux motor technology, and installed it in a London Taxi Cab. The DuoDrive switchable series/parallel hybrid system has demonstrated a 60% improvement in fuel economy compared to a conventional taxi when operated over an urban drive cycle. As with many hybrid vehicles, a large part of this improvement is attributed to effective and efficient recapture of braking energy. The amount of braking energy that can be recovered, and the efficiency with which it can be returned to the road will therefore have a significant impact on the overall fuel economy of the vehicle. One factor that limits the amount of energy that can be recovered is the allowable charge rate of the battery, as braking events are usually high power and in a hybrid vehicle the battery size is generally small. The vehicle described in this paper has an energy storage system comprised of high power ultra-capacitors and a high energy lithium ion battery connected through a DC/DC converter. This allows efficient, high power transfer under regenerative braking and acceleration, and similarly efficient energy storage over longer timescales. Managing the power flow through the DC/DC converter and therefore the ultra-capacitor voltage, is a key control parameter that affects the efficiency of the overall system. This paper presents the energy storage system layout and demonstrates how different DC/DC converter control strategies can affect the system energy efficiency. Full article

Recently the thermoelectric-photovoltaic (TE-PV) hybrid energy system for hybrid electric vehicles has been proposed. However, the output voltage of this TE-PV hybrid energy system is governed by the voltage of the battery, which is affected by the state of charge of the battery and the charging/discharging current. Furthermore, in order to improve the power density and life cycle of the battery, the ultracapacitor (UC) has been proposed to hybridize with the battery to form a hybrid energy storage system. In this paper, a multi-hybrid energy system is proposed for HEVs, which incorporates the advantages of the TE-PV hybrid subsystem and the ultracapacitor-battery (UC-B) hybrid subsystem. On the one side, the TE-PV hybrid subsystem can provide the higher fuel economy due to the increase of on-board renewable energy, the better energy security due to the use of multiple energy sources, and the higher control flexibility due to the coordination for charging the same pack of batteries. On the other side, the UC-B hybrid subsystem can provide faster transient power, higher power density and longer battery lifetime. Detailed simulations results are given to highlight the effectiveness of the designed multi-hybrid energy system. Full article

This paper describes a controlling method of motor-terminal surge voltage and induced-electromagnetic interference (EMI) noise which is effective in electric vehicles (EVs) with high density packaging structures. First, high frequency circuit parameters (HFCPs) to influence surges occurring at the motor terminals when a motor is connected to a pulse width modulation (PWM) inverter with short leads are clarified through transient circuit analyses and experiments. Then, a controlling method of the surge voltage and induced-EMI noise is proposed which uses a multi-layer power printed circuit. By applying the clarified HFCPs to an equivalent circuit expressing the multi-layer power printed circuit, damping resistance and bypass capacitance for suppressing surge voltage and the induced-EMI noise are determined. The effectiveness of the surge voltage and EMI noise controller using the values obtained through the analyses is verified through simulations and experiments. Full article

Fuel cell vehicles are considered to be a viable solution to problems such as carbon emissions and fuel shortages for road transport. Proton Exchange Membrane (PEM) Fuel Cells are mainly used in this purpose because they can run at low temperatures and have a simple structure. Yet to make this technology commercially viable, there are still many hurdles to overcome. Apart from the high cost of fuel cell systems, high maintenance costs and short lifecycle are two main issues need to be addressed. The main purpose of this paper is to review the issues affecting the reliability and lifespan of fuel cells and present the state of the art in fuel cell condition monitoring and maintenance. The Structure of PEM fuel cell is introduced and examples of its application in a variety of applications are presented. The fault modes including membrane flooding/drying, fuel/gas starvation, physical defects of membrane, and catalyst poisoning are listed and assessed for their impact. Then the relationship between causes, faults, symptoms and long term implications of fault conditions are summarized. Finally the state of the art in PEM fuel cell condition monitoring and maintenance is reviewed and conclusions are drawn regarding suggested maintenance strategies and the optimal structure for an integrated, cost effective condition monitoring and maintenance management system. Full article

Proton exchange membrane fuel cell (PEMFC) operating at elevated temperature has many advantages compared to low temperature prototypes. With the adoption of short side chain, low equivalent weight (EW) perfluorosulphonic acid (PFSA) membrane, a 100W PEMFC stack was built and evaluated at an elevated temperature of 95℃. For the purpose of studying the effect of anode relative humidity (RH) on fuel cell performance, the stack was tested with (1) 60% RH air and 70% RH H₂, (2) 60% RH air and dry H₂, respectively under different temperatures. Furthermore, the CO tolerance of the stack was investigated at low and elevated temperatures in the presence of 5ppm, 10ppm and 20ppm CO/H₂, respectively. The results demonstrated that the stack performance with dry H₂ was more than 30% inferior to that with H2 of 70% RH, and the cell consistency deteriorated under higher temperature and lower anode RH. The polarization curves of the stack employed fuel rich in CO indicated that elevating the operating temperature to 95℃ could improve the anode catalyst tolerance to CO, and the CO poisoning effect on cell polarization is slight at low current densities. Full article

The National Fuel Cell Electric Vehicle Learning Demonstration is a U.S. Department of Energy (DOE) project that started in 2004. The purpose of this project is to conduct an integrated field validation that simultaneously examines the performance of fuel cell vehicles and the supporting hydrogen infrastructure. The DOE’s National Renewable Energy Laboratory (NREL) has now analyzed data from over five years of the seven-year project. During this time, over 144 fuel cell electric vehicles have been deployed, and 23 project refueling stations were placed in use. We have analyzed data from over 430,000 individual vehicle trips covering 2,500,000 miles traveled and over 130,000 kg hydrogen produced or dispensed. During 2010, two of the four project teams will be concluding their involvement in the project, and the other two are continuing. Thus we will be able to focus our analysis efforts on a smaller number of vehicles and stations and enter into a new stage of learning for this project. This will allow us to dig deeper into the data to provide additional technical value to the two remaining teams as they improve their systems’ technical performance in preparation for pre-commercial launch of larger fleets of vehicles in California and New York. It will also give us an opportunity to gather data and analyze performance of improved vehicles compared to those that have been previously demonstrated, since these vehicles are one step closer to commercially available customer vehicles. Full article

Proper operating temperature range and homogenous temperature distribution are important to proton exchange membrane fuel cell (PEMFC). For the elevated temperature PEMFC water is not suitable to be used as coolant due to high operating temperature. Instead, air can be chosen as coolant because of the relative large temperature difference between fuel cell itself and the ambient air. In this paper, four types of forced air-cooling modes for elevated temperature PEMFC were discussed, and influences of other factors such as cooling air inlet velocity and thermal conductivity of bipolar plate material and fins on heat dissipation and temperature distribution were investigated. Three-dimensional computational fluid dynamics (CFD) method was employed to investigate fluid flow and heat transfer in the elevated temperature PEMFC on a 250 cm2 single cell level. The temperature distribution fields on the active area of MEA were obtained and compared. One optimized mode, with suitable cooling air inlet velocity and bipolar plate material, was determined for future experimental study. Full article

Proton exchange membrane (PEM) fuel cells experience performance degradation, such as reduction in efficiency and life, as a result of poisoning of platinum catalysts by airborne contaminants. The best method for addressing fuel cell air contamination is by the inclusion of adsorptive filtration with a cathode air filter. In this paper, simulation for chemical adsorption behavior of air filter has been studied, which is based on Fluent. The adsorption of SO₂ was simulated in the air filter, which structure was designed and optimized for a 5kW fuel cell stack system. Not only the distribution of SO₂ capacity with time in filter could be shown, but also the durability of filter can be evaluated. Furthermore, the velocity of flow and pressure drop of filter also were simulated. The simulation study for chemical adsorption and hydrodynamics in fuel cell cathode air filter help to optimize air filter to be durable and effective. Full article

The purpose of this study is to analyze and to design for the hybrid power systems with variable inertia flywheel while the hybrid power system consists of 1 power plant, 1 variable inertia flywheel which is used as the energy storage device, a planetary gear set, and a set of actuators. First, the kinematic and kinetic equations of the hybrid power system are developed in order to establish the relationships of the speed and torque of all elements, and the specific speed and torque of the output needed for the vehicle can be found by using the software “ADVISOR” in various operation modes. Then, with the prescribed mechanical brake energy recovery system model and a control model, a comprehensive analysis can be achieved. Finally, various driving modes, such as ECE, ECE+EUDC and New York Bus driving mode are investigated in order to demonstrate the characteristics of the hybrid power system. The numerical results show and conclude the effectiveness of the variable inertia flywheel, and the improvement on the efficiency of hybrid power systems. Copyright Form of EVS25. Full article