LC series resonance high frequency chain matrix type half-bridge inverter topology and modulation method

Abstract

The invention relates to an LC series resonance high frequency chain matrix type half-bridge inverter topology and a modulation method. The topology comprises a half-bridge LC series resonance inverter, a high-frequency transformer T, a matrix converter and a CL type filter. The modulation method comprises steps that SPWM waves generated in a SPWM signal generation link are processed through series resonance modulation logics to acquire driving signals of a transformer front-level LC series resonance inverter and a transformer back-level matrix converter, a work duty ratio of an excitation resonance work state of a transformer front-level resonance circuit is made to be controllable within a half period, and output load side energy transmission control is realized; the transformer back-level matrix converter is taken as a common current type inverter to control, switching of a switch tube during a transformer zero current output period is carried out to realize a zero current switch, a voltage overshoot problem caused by break of a transformer secondary side leakage current flow path can be avoided, and bidirectional energy flow is realized. The method has advantages of small-quantity power conversion grades, small-quantity switch tubes, simple control and high circuit stability.

Description

technical field [0001] The invention relates to the field of modulation and control of power electronic power converters, in particular to a half-bridge resonance current modulation method of a single-phase LC series resonance type high-frequency chain matrix inverter. Background technique [0002] An inverter is a topological device that converts DC power into AC power. The high-frequency link inverter uses high-frequency transformers instead of power-frequency transformers to overcome the shortcomings of traditional transformers such as large volume, large noise, and high cost. The conversion process of the high-frequency chain matrix inverter has three power characteristics of DC / HFAC / LFAC, among which, HFAC: high-frequency AC, LFAC: low-frequency AC. It can be seen that DC / AC, that is, DC / AC inverter link, appears in this type of inverter, which is located on the primary side of the transformer, and AC / AC, that is, AC / AC conversion link, which is also often called a cyc...

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Problems solved by technology

At present, there are mainly the following safe commutation strategies: ① Soft switching can be realized by adding active clamps to suppress voltage overshoots, but the introduced clamp circuit increases the cost, and the added controllable power tube also makes the control more efficient. Complex; ②The unipolar and bipolar phase-shift control strategy realizes the natural commutation of the inductor current by means of the commutation overlap of the cycloconverter, and realizes the ZVS of the power tube, but there are problems such as difficult control of the commutation overlap time; ③The series resonant circuit is introduced into the front-end inverter to realize the soft commutation of the power tube. At this time, the switching of the power tube is required to occur at the moment of zero current, and the control of the output energy needs to judge the resonant working state of the resonant circuit, which makes the control method complicated; ④ Compared with the full-bridge resonant inverter, the half-bridge resonant inverter has fewer power switches and less energy loss, and the logic combination of the half-bridge resonant current modulation method is simple and easy to understand

[0004] However, although the above strategy can achieve safe commutation, it makes the modulation and control of the inverter more complex, resulting in reduced system reliability and affecting the popularization and use of this type of converter.

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