Introduction

Configuration of the proposed topology

Operating principle of the proposed inverter

Parameter design of passive and active components

Performance comparison with other high boost zsi topologies

Power loss analysis and efficiency comparison

Simulation and experimental results

Conclusion

References

Abstract

This paper proposes a new high boost quasi-Zsource inverter (qZSI) with combined two quasi-Z-source networks, which has a common ground between the input source and the inverter bridge. Compared with other non-coupled inductor-based (q)ZSIs, by using the same total number of passive and active components, the proposed inverter provides higher boost capability, requires smaller inductance and capacitance values at the impedance network, achieves lower voltage stress across the active switching devices, and has higher modulation index for the inverter bridge to improve the output waveform quality. Although the proposed inverter has the same voltage boost factor with the enhanced boost (quasi-)Z-source inverters (EB-ZSI and EB-qZSI), the proposed scheme has lower capacitor voltage stress than EB-ZSI and has higher efficiency than EB-qZSI. The topological configuration, operating principles, power loss analysis, and performance comparison with other high boost (q)ZSIs are presented. Finally, both simulations and experimental results are given to validate the aforementioned characteristics of the proposed topology.

Introduction

The traditional three-phase voltage source inverter (VSI) and current source inverter (CSI) are the most commonly used two kinds of pulse width modulation (PWM) inverter topologies. And, they have been widely used in many industrial applications such as uninterruptible power supply, ac motor drives, and hybrid electric vehicles [1]-[2]. However, both of them still exist some major problems. For the traditional VSI, its ac output voltage is always lower than the dc input voltage; thus, the VSI only performs a buck converter for the dc-ac power conversion. Similarly, the traditional CSI only performs a boost converter due to its ac output voltage is always greater than the original dc input voltage. For some applications where both voltage buck and boost capabilities are needed, an additional dc-dc converter will be required in VSI and CSI, which induces a two-stage power conversion, to obtain the desired ac output voltage. As a result, the volume and size of the whole system will be increased, leading to high weight, high cost and low overall efficiency[3]. To overcome the aforementioned limitations in traditional VSIs, a novel, simple and efficient design of Z-source inverter (ZSI) was firstly proposed by Peng in 2003[4], as shown in Fig. 1(a). By using the Z-source network, which consists of two inductors and two capacitors connected in an X-shape, to replace the traditional dc link in VSI, the ZSI can achieve both voltage buck and boost operating capabilities with a single-stage power conversion. In addition, both the semiconductor switches of each phase leg can be turned on simultaneously, which implies that the anti-interference ability of the inverter can be further improved, especially for the switches misgating-on caused by the electromagnetic interference noise.