Single-phase half-bridge three-level circuit and inverter

Abstract

The embodiment of the invention discloses a single-phase half-bridge three-level circuit, which comprises a first direct current input end, a midpoint level end, a second direct current input end, a first switch device, a second switch device, a third switch device, a fourth switch device, a fifth switch device and a sixth switch device, a fifth diode, a sixth diode, a seventh diode, an eighth diode, a ninth diode and a tenth diode. The embodiment of the invention also discloses an inverter with the single-phase half-bridge three-level circuit. In occasions simultaneously requiring unity power factor and non-unity power factor application, the selection range of the switch devices is wide, in addition, the loss of the switch devices can be reduced, the service lives of the switch devices are prolonged, and the integral conversion efficiency is improved.

Description

Technical field [0001] The invention belongs to the field of power electronics, and particularly relates to a single-phase half-bridge three-level circuit and a three-level inverter including the circuit. Background technique [0002] The traditional I-shaped three-level circuit such as figure 1 As shown, T1, T2, T3, and T4 are switching devices, D1, D2, D3, and D4 are anti-parallel diodes of T1, T2, T3, and T4, respectively, and D1, D2, D3, and D4 are body diodes of the switching devices. The mode of I-shaped three-level circuit working at unity power factor is shown in Figure 2. Figure 2a In, the current flows from terminal M to AC output A through T1 and T2; Figure 2b In, the current flows from terminal O to AC output A through T1 and T2; Figure 2c In, the current flows from the AC output A to the N terminal through T3 and T4; Figure 2d In, the current flows from AC output A to terminal O through T3 and D6. The modal of the I-shaped three-level circuit working at non-unity...

AI Technical Summary

Problems solved by technology

Therefore, there are the following technical problems in applications where unity power factor and non-unity power factor are required at the same time: (1) When selecting T2 and T3, it is necessary to consider both the switching performance and conduction performance of the device. Under the current semiconductor technology, Only a compromise can be considered when choosing, resulting in low efficiency when working at unit power factor; (2) Since T2 and T3 both participate in work at unit power factor and non-unity power factor, the loss is large, which is not conducive to heat dissipation and reduces The service life of the device is reduced, and the conversion efficiency of the circuit is reduced; (3) The reactive current needs to pass through the body diodes D1, D2, D3, and D4 of T1, T2, T3, and T4, and the loss is large, which is not conducive to heat dissipation of the device, reducing The service life of the device is shortened, the increase of the switching frequency is limited, and the conversion efficiency of the circuit is also reduced.

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