ANPC type three-level inverter, modulation method and electrical equipment

Abstract

The invention discloses an ANPC type three-level inverter, a modulation method and electrical equipment. The modulation method comprises steps that, a leg voltage instruction stands t1, t2 and t3 switch state change moments during transition from a positive half cycle to a negative half cycle, from the t1 moment, a T3 and a T6 are turned on, and a T2 and a T5 are maintained to turn on; from the t2 moment, the T2 and the T5 are turned off; from the t3 moment, the T3 is turned off, and the T4 is turned on; the Vo sequentially stands t11, t12 and t13 moments during transition from a negative half cycle to a positive half cycle, from the t11 moment, the T2 and the T5 are turned on, the T3 and the T6 are maintained to turn on; from the t12 moment, the T3 and the T6 are turned off; from t13 moment, the T2 is turned off, and the T1 is turned on; except two time segments of t1-t3 and t11-t13, a traditional ANPC type three-level inverter modulation method is followed in other time, so generation of a relatively long commutation loop during turning off a switch tube near a zero crossing point of the leg voltage instruction can be avoided.

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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