Series-parallel connection output tri-level half-bridge inverter and half period hysteresis control method thereof

Abstract

The invention discloses a series-parallel connection output tri-level half-bridge inverter and a half period hysteresis control method thereof. The inverter comprises a power supply, a first tri-level half-bridge inverter, a second tri-level half-bridge inverter, an output filter circuit and a load. Each of the tri-level half-bridge inverters comprised in the method works separately; when in the half period with positive output inductive current, an upper bridge leg of each tri-level half-bridge inverter works; when in the half period with negative output inductive current, a lower bridge leg of each tri-level half-bridge inverter works. Under the mode of half period current hysteresis control, the inverter does not have circulating current and reduces the conducting times of a body diode, thus reducing the loss caused by reverse restoration of the diode, improving the efficiencies of the circuit and the switch and further reducing the volume and weight of a filter. Meanwhile, when in the whole working process, the circuit can work without dead area.

Description

technical field [0001] The invention relates to a three-level half-bridge inverter and a control method thereof, in particular to a series-parallel output three-level half-bridge inverter and a half-period hysteresis control method thereof. Background technique [0002] In the application of the three-level half-bridge inverter, due to the existence of the through problem, the common control method (such as unipolar SPWM) must set the dead time. During the dead time, the state of the output voltage of the bridge arm changes. , the waveform quality will deteriorate. In addition, due to the serious conduction problem of the body diode in the working process, it will bring a series of problems such as loss, such as the invention of the publication number CN1595782 applied for on July 1, 2004: double-output double-step-down half-bridge inverter and control, modulation method. [0003] For the current common series-parallel dual-output inverter solutions, there are the followin...

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Problems solved by technology

[0002] In the application of the three-level half-bridge inverter, due to the existence of the through problem, the common control method (such as unipolar SPWM) must set the dead time. During the dead time, the state of the output voltage of the bridge arm changes. , the waveform quality will deteriorate

[0005] This kind of dual-output inverter is composed of two half-bridge inverters whose input side is connected in parallel and the output side is connected in series. , the performance of the body diode is poor, and the reverse recovery causes a large loss, which limits the increase of the switching frequency, so that the volume and weight are difficult to reduce;

[0009] This dual-output double-step-down half-bridge inverter is composed of two identical double BUCK circuits, the bridge arm has no direct connection, no body diode anti-recovery problem, high efficiency, but its output bridge arm output is a two-level voltage , the harmonic content is large, and there are four inductors in the main circuit topology, the volume and weight are large

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