Control method and device of I-type three-level circuit

Abstract

The invention discloses a control method and device of an I-type three-level circuit. With the control method and device adopted, the zero-voltage switching on of the switching tubes of a high-frequency bridge arm can be realized, the loss of the circuit can be reduced, and the efficiency of the circuit can be improved. The control method comprises the following steps that: the inductance current of an inductor which is connected with each high-frequency bridge arm in an operating state in the I-type three-level circuit is detected; in the positive half cycle of the voltage of the alternating current wiring end of the I-type three-level circuit, when the freewheel switching tube of the high-frequency bridge arm connected with the inductor is in an on state, and the main switching tube of the high-frequency bridge arm is in an off state, if it is detected that the inductance current does not reach preset negative current, the freewheel switching tube in the on state is controlled to be in the on state continuously, and the main switching tube in the off state is controlled to be in the off state continuously; and if it is detected that the inductance current reaches the preset negative current, the freewheel switching tube in the on state is controlled to be switched off, and the main switching tube in the off state is controlled to be switched on.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a control method and device for an I-type three-level circuit. Background technique [0002] At present, various I-level circuits have been widely used in many fields due to their high efficiency. figure 1 Shown is a common I-type three-level circuit, including switch tubes S1, S2, S3 and S4, clamping diodes Dc1 and Dc2, inductor L, bus capacitor Co+ and Co-; diodes D1, D2, D3 and D4 are body diodes of switch tubes S1, S2, S3 and S4 or external anti-parallel diodes, and capacitors Coss1, Coss2, Coss 3 and Coss 4 are equivalent junction capacitances of switch tubes S1, S2, S3 and S4, respectively; Capacitors Cdc1 and Cdc2 are the equivalent junction capacitances of clamping diodes D1 and D2, respectively; where: [0003] The switch tubes S1, S2, S3 and S4 are connected in sequence to form a high-frequency bridge arm, and the bus capacitors Co+ and Co- are connected in ...

AI Technical Summary

Problems solved by technology

[0007] The embodiment of the present invention provides a control method and device for an I-type three-level circuit, which is used to solve the problem that the high-frequency bridge arm switch tube cannot be turned on at zero voltage in the prior art

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