Research On Fixed-frequency ZVS Inverter Technique Based On Hysteresis Current Control

Inverter is very important in power electronics field,and has been widely applied in uninterrupted power supply,photovoltaic power generation system,the frequency control of AC motor,household appliances,vehicle system and so on.At present,topological structure and control technique are studied to improve inverter performance,improve efficiency and reduce cost.Based on relevant theoretical knowledge and key technologies,a fixed-frequency ZVS inverter technique based on hysteresis current control is proposed in this paper.This technique requires no additional auxiliary circuits and can be employed for half-bridge or full-bridge inverter topologies.To reduce switching loss,the body capacitors and the inductor construct a resonant network to generate zero voltage condition.Based on controlled-type soft-switching hysteresis current control,the double triangular carrier method is produced to achieve fixed switching frequency,which can simplify filter design and reduce harmonic.When hysteresis current control is the object of study,the characteristics of the single-band hysteresis current control and double-band hysteresis current control are analyzed as well as the unfixed switching frequency.Fixed switching frequency strategies are summed up after that,and can be classified as timing method and dynamic threshold scaling method.What's more,two typical fixed switching frequency strategies are analyzed,and one of them is verified by experiment.The characteristics and operation principle of controlled-type soft switching are analyzed in this paper.On the basis,experimental study on compressing the frequency variation with the double triangular carrier method is proposed and fundamentally the combination of triangular carrier control and hysteresis current control.The proposed control retains the benefit of the controlled-type soft switching achieving zero switching loss and tackles the drawback of the standard hysteresis control having unfixed switching frequency.Simulation results are given to show the effectiveness and feasibility.Finally,a digital control method based on DSP is produced,and the hardware circuits and software implementation are analyzed.On the basis,a whole experimental circuit is set up.At last,experimental results are carried out to prove the soft switching and fixed switching frequency are achieved under this current control method.