High-gain Z-source inverter

Abstract

The invention provides a high-gain Z-source inverter, comprising a three-phase inverter, which is composed of a direct-current voltage source and a three-phase inversion bridge. The high-gain Z-source inverter further comprises a Z-source network, which is composed of a power diode, a switch inductor and a capacitor. The high-gain Z-source inverter is characterized in that a single inductor is replaced by a branch circuit of the switch inductor; the head end of the Z-source network is connected with the positive electrode of a power supply; the tail end of the Z-source network is connected to the positive end of the three-phase inversion bridge; and the inversion bridge and the power supply are grounded commonly. Compared with the traditional Z-source inverter, the Z-source inverter disclosed by the invention is capable of improving the boost capacity of the inverter, realizing a high modulation factor and improving the output quality of the whole inverter; and simultaneously, the voltage stress of the Z-network capacitor can be effectively reduced so as to reduce the volume and the weight of the inverter.

Description

1. Technical field [0001] The high-gain Z-source inverter involved in the present invention belongs to power electronic converters. 2. Background technology [0002] People are paying more and more attention to clean energy. Wind power generation, photovoltaic power generation and fuel cells are favored by the industry, but the DC voltage output by wind power generation, photovoltaic power generation and fuel cell systems fluctuates greatly and cannot directly supply power to users. In order to achieve stable power output for step-up and step-down, a DC / DC step-up circuit is added to the front stage of the inverter bridge as shown in the attached figure 1 As shown, but the link of the DC / DC converter increases the cost of the system and reduces the efficiency of the system, and the two-stage structure increases the complexity of the system control. [0003] Literature (F.Z.Peng, "Z-source Inverter," IEEE Trans.on Industry Applications, vol.39, no.2, pp, 504-510, March / April...

AI Technical Summary

Problems solved by technology

[0004] Although the Z-source inverter can theoretically have infinite boost capability, it cannot actually achieve infinite gain due to the influence of component parasitic parameters, and too high boost will increase system loss and instability; on the other hand, The through duty cycle and the modulation factor are mutually restrictive, and increasing the duty cycle means reducing the modulation factor, which will inevitably increase the voltage stress of the switching device during the effective period and the current stress during the through period, and increase the cost of the system, so Traditional Z-source inverters have very limited boost capability

Images