A Study on DC-Link-Type Quasi-Switched-Boost Inverters with Improved Voltage Gain

The DC-link type quasi-switched boost inverters (DCL-qSBIs) are known as one of impedance-source inverters with low voltage stress on their additional switch, diode, and capacitor. However, the voltage gain of DCL-qSBIs is still low. This paper presents DCL-qSBIs with a modified PWM control strategy. The modified PWM control strategy based DCL-qSBIs improve voltage gain, reduce the conduction loss, and decrease the voltage stress of devices in the switched-boost network. The operating principle of DCL-qSBIs is presented. The 1 kVA-prototype three-phase DCL-qSBI and quasi-Z-source inverter (qZSI) is built to evaluate the performance of the inverters at output voltage ratio of 1.05 to 1.6. The measured efficiency of DCL-qSBI is 0.5 to 1% higher than that of the qZSI at all powers and boost levels tested.