# Analysis of Steady-State Characteristics for a Newly Designed High Voltage Gain Switched Inductor Z-Source Inverter

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## Abstract

**:**

## 1. Introduction

- The detailed analytical model has been developed along with the analysis of the ripples in the inductor currents and capacitor voltages.
- This work includes more analyses associated with the switching device power and efficiency calculation.
- The analytical models reveal several advanced features of the proposed topologies such as the reduced capacitor voltage stress for the same boost factor; improved boosting capability for the same input voltage and shoot-through duty ratio, improved efficiency, reduced inrush current, and significantly improved dynamic voltage compensation capability as compared to all existing topologies.

## 2. Operating Characteristics of the Proposed SL-SBZSI Topology

#### 2.1. Shoot-Through Operating Mode

#### 2.2. Non-Shoot-Through Operating Mode

## 3. Performance Characteristics of Proposed SL-SBZSI

#### 3.1. Mathematical Modeling of Proposed SL-SBZSI

#### 3.2. Analysis of Ripples in the Inductor Current for the Proposed SL-SBZSI

#### 3.3. Analysis of Ripples in the Capacitor Voltage for the Proposed SL-SBZSI

#### 3.4. Inverter Switching Device Power

- Current to load during the non-shoot-through mode and
- Current through switches during the shoot-through mode.

## 4. Inverter Switching Control Method

## 5. Comparative Analysis for the Capacitor Voltage Stress

## 6. Calculation of Power Loss and Efficiency of the Proposed SL-SBZSI

## 7. Simulation Results

- Analysis of the voltage and current characteristics with the fixed input voltage and shoot-through duty ratio.
- Analysis of the voltage and current characteristics with the fixed input voltage and boost factor but different shoot-through duty ratios.
- Analysis of the voltage and current characteristics with the fixed input voltage but slower variations in the shoot-through duty ratio.
- Analysis of dynamic voltage compensation characteristics.

- Case 1: analysis of the voltage and current characteristics with the fixed input voltage and shoot-through duty ratio.

- Case 2: analysis of the voltage and current characteristics with the fixed input voltage and boost factor but different shoot-through duty ratios.

- Case 3: analysis of the voltage and current characteristics with the fixed input voltage but slower variations in the shoot-through duty ratio.

- Case 4: analysis of dynamic voltage compensation characteristics

## 8. Experimental Validation

## 9. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## References

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**Figure 3.**Key switching waveforms for the switched inductor assisted strong boost Z-source inverter (SL-SBZSI).

**Figure 4.**Characteristics curve: (

**a**) boost factor, (

**b**) capacitor voltage stress—high, (

**c**) capacitor voltage stress—low.

**Figure 10.**Simulation results (case 1): (

**a**) traditional modified capacitor assisted Z-source inverter (MCA-ZSI). (

**b**) Proposed SL-SBZSI. From top to bottom: DC-link voltage, ${V}_{pn}$; capacitor voltage, ${V}_{C}$ and output line voltage, ${V}_{ab}$. Enlarge waveform: (

**c**) traditional MCA-ZSI. (

**d**) Proposed SL-SBZSI. From top to bottom: DC-link voltage, ${V}_{pn}$; capacitor voltage; ${V}_{C1}$ and capacitor voltage; ${V}_{C3}$.

**Figure 11.**Simulation results (case 1): (

**a**) traditional MCA-ZSI. (

**b**) Proposed SL-SBZSI. From top to bottom: input current, ${I}_{in}$; shoot-through current; ${I}_{pn}$ and inductor current, ${I}_{L1}$. Enlarge waveform: (

**c**) Traditional MCA-ZSI. (

**d**) Proposed SL-SBZSI. From top to bottom: input current, ${I}_{in}$; shoot-through current; ${I}_{pn}$ and inductor current, ${I}_{L1}$.

**Figure 13.**Simulation results (case 2): (

**a**) traditional MCA-ZSI. (

**b**) Proposed SL-SBZSI. From top to bottom: DC-link voltage, ${V}_{pn}$; capacitor voltage, ${V}_{C1}$ and capacitor voltage, ${V}_{C3}$. Enlarge waveform: (

**c**) Traditional MCA-ZSI. (

**d**) Proposed SL-SBZSI. From top to bottom: input current, ${I}_{in}$; shoot-through current, ${I}_{pn}$ and inductor current, ${I}_{L1}$.

**Figure 14.**Simulation results: (

**a**) soft-start waveform in case 3, and (

**b**) dynamic voltage compensation in case 4.

**Table 1.**Parameters associated with the performance of the switched inductor assisted strong boost Z-source inverter (SL-SBZSI) and modified capacitor assisted Z-source inverter (MCA-ZSI) for the same ${D}_{S}$ and ${V}_{in}$

No | Parameters | MCA-ZSI | Proposed SL-SBZSI |
---|---|---|---|

1 | Boost factor, B | $\frac{(1-{D}_{S})}{(1-5{D}_{S}+4{{D}_{S}}^{2})}$ | $\frac{(2-3{D}_{S}-5{{D}_{S}}^{2})}{2(1-7{D}_{S}+12{{D}_{S}}^{2})}$ |

2 | Capacitor voltage, ${V}_{C1}$ | $\frac{(1-2{D}_{S})(1-{D}_{S})}{(1-5{D}_{S}+4{{D}_{S}}^{2})}{V}_{in}$ | $\frac{{D}_{S}(2-5{D}_{S})}{(1-7{D}_{S}+12{{D}_{S}}^{2})}.{V}_{in}$ |

3 | Capacitor voltage, ${V}_{C3}$ | $\frac{{D}_{S}(1-{D}_{S})}{(1-5{D}_{S}+4{{D}_{S}}^{2})}{V}_{in}$ | $\frac{3{D}_{S}}{2(1-4{D}_{S})}.{V}_{in}$ |

4 | Voltage gain, G | $\frac{{(1-{D}_{S})}^{2}}{(1-5{D}_{S}+4{{D}_{S}}^{2})}$ | $\frac{(1-{D}_{S})(2-3{D}_{S}-5{{D}_{S}}^{2})}{2(1-7{D}_{S}+12{{D}_{S}}^{2})}$ |

5 | Inductor current, $\overline{{I}_{L}}$ | $\frac{(1-{D}_{S})({I}_{in}-{I}_{i})}{4{D}_{S}}$ | $\frac{3{(1-{D}_{S})}^{2}{(2-3{D}_{S}-5{D}_{S}^{2})}^{2}}{32{R}_{L}{(1-7{D}_{S}+12{D}_{S}^{2})}^{2}}.{V}_{in}$ |

6 | Input current, ${I}_{in}$ | $\frac{(1-{D}_{S}){I}_{i}}{(1-5{D}_{S}+4{{D}_{S}}^{2})}$ | $\frac{3{(1-{D}_{S})}^{2}{(2-3{D}_{S}-5{D}_{S}^{2})}^{2}.{V}_{in}}{32{R}_{L}{(1-7{D}_{S}+12{D}_{S}^{2})}^{2}}+{I}_{i}$ |

7 | ST current, ${I}_{pn}$ | $4{I}_{L1}$ | $4{I}_{L1}+{I}_{L3}$ |

8 | Load current, ${I}_{o}$ | $\frac{(1-{D}_{S}){V}_{pn}}{{R}_{L}}$ | $\frac{(1-{D}_{S}){V}_{pn}}{{R}_{L}}$ |

No | Parameters | Symbols | Value |
---|---|---|---|

1 | Input voltage | ${V}_{in}$ | 50 V |

2 | Capacitance | ${C}_{1}={C}_{2}={C}_{3}={C}_{4}$ | 500 $\mathsf{\mu}$F |

3 | Inductance | ${L}_{1}={L}_{2}={L}_{3}={L}_{4}={L}_{5}$ | 700 $\mathsf{\mu}$H |

4 | Switching frequency | ${f}_{S}$ | 10 kHz |

5 | Output filter | ${L}_{f},{C}_{f}$ | 1 mH, 110 $\mathsf{\mu}$F |

6 | Load | ${R}_{L}$ | 60 $\mathsf{\Omega}$/phase |

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**MDPI and ACS Style**

Subhani, N.; Kannan, R.; Mahmud, M.A.; Roy, T.K.; Romlie, M.F. Analysis of Steady-State Characteristics for a Newly Designed High Voltage Gain Switched Inductor Z-Source Inverter. *Electronics* **2019**, *8*, 940.
https://doi.org/10.3390/electronics8090940

**AMA Style**

Subhani N, Kannan R, Mahmud MA, Roy TK, Romlie MF. Analysis of Steady-State Characteristics for a Newly Designed High Voltage Gain Switched Inductor Z-Source Inverter. *Electronics*. 2019; 8(9):940.
https://doi.org/10.3390/electronics8090940

**Chicago/Turabian Style**

Subhani, Nafis, Ramani Kannan, Md. Apel Mahmud, Tushar Kanti Roy, and Mohd Fakhizan Romlie. 2019. "Analysis of Steady-State Characteristics for a Newly Designed High Voltage Gain Switched Inductor Z-Source Inverter" *Electronics* 8, no. 9: 940.
https://doi.org/10.3390/electronics8090940