A kind of anpc type three-level inverter, modulation method and electrical equipment

Abstract

The present application discloses an ANPC type three-level inverter, a modulation method and electrical equipment. The modulation method includes: when a bridge arm voltage command transitions from a positive half cycle to a negative half cycle, the three switch states of t1, t2 and t3 change in sequence. Time: From time t1, T3 and T6 are turned on, while keeping T2 and T5 turned on; from time t2, T2 and T5 are turned off; from time t3, T3 is turned off and T4 is turned on; Vo passes through the transition from the negative half cycle to the positive half cycle. t11, t12, t13: From time t11, T2 and T5 are turned on, while keeping T3 and T6 turned on; from time t12, T3 and T6 are turned off; from time t13, T2 is turned off, and T1 is turned on; except for t1~t3, t11~ During the two periods of t13, the traditional ANPC three-level inverter modulation method is still followed in the rest of the time to avoid a long commutation loop when the switch tube is turned off near the zero-crossing point of the bridge arm voltage command.

Description

technical field [0001] The invention relates to the technical field of power electronics, and more specifically, relates to an ANPC type three-level inverter, a modulation method and electrical equipment. Background technique [0002] The main circuit topology of the ANPC (Active Neutral-point-clamped) type three-level inverter is as follows: figure 1 As shown, it includes 6 switching tubes T1~T6, 6 diodes D1~D6 and 2 supporting capacitors C1~C2, where: the output terminal of T1 is connected to the input terminal of T2 and T5, and the input terminal of T4 is connected to the terminal of T3 and T6 Output terminal, the output terminal of T5 is connected to the input terminal of T6, the input terminal of T1 is connected to the DC positive bus DC+, the output terminal of T4 is connected to the DC negative bus DC-, the output terminal of T2 and the input terminal of T3 are connected to the midpoint O of the DC bus , the output terminal of T5 is used as the AC output terminal AC;...

AI Technical Summary

Problems solved by technology

[0004] However, near the zero-crossing point of the bridge arm voltage command Vo, a longer commutation loop will appear when the switch tube is turned off. The longer the commutation loop, the greater the inductance of the stray inductance in the loop. The higher the peak voltage, if the peak voltage exceeds the withstand voltage value of the switch tube, it will cause the switch tube to blow up

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