Research On High Efficiency Single-phase Full-bridge Resonant Pole Soft-switching Inverter

The purpose of this paper is to ensure the efficient conversion of energy in the full load range of single-phase full-bridge resonant soft-switching inverter and to provide effective solutions for energy system optimization.This is of great significance to the implementation of the national energy conservation strategy,the promotion of advanced equipment manufacturing level in Liaoning industrial base and the alleviation of resource pressure in China.Under the support of the scientific research project of Liaoning provincial department of education(L2019017),four high performance single-phase full-bridge resonant pole soft-switching inverters are designed.The working mode and dynamic resonance track of inverter are analyzed in detail.The specific parameter design process and soft-switching realization rules are given.The optimal strategy to improve efficiency is explored in depth in theory.The authenticity of the method and conclusion is verified by simulation.The main innovations in this paper are as follows:1.In the second chapter,a new topology of high efficiency single-phase full-bridge passive resonant inverter is proposed,which uses the low energy consumption auxiliary resonant network on the inverter bridge arm to realize the soft switch of power semiconductor devices,so as to save energy and reduce consumption.The switch tube of each bridge arm shares a set of resonant units,which significantly reduces the components attached to the main switch and does not complicate the control of the inverter.In addition,when the inverter works in the dead zone,the load current can continue to flow through the auxiliary resonant circuit,reducing the negative impact of dead zone time on the output waveform of the inverter.2.In view of the shortcomings of the topology proposed in the second chapter,such as more passive components,complex auxiliary buffer circuit and mutual coupling of resonance process.In the second chapter,a single-phase full bridge resonant pole soft-switching topology with a single auxiliary switch is proposed.The auxiliary circuit is connected with the inverter bridge arm,and only contains one auxiliary switch and a small number of passive devices,which simplifies the auxiliary buffer circuit The decoupling of harmonic process reduces the hardware cost of auxiliary circuit and the system vibration caused by coupling resonance,and improves the dynamic response and practicability of inverter.In the working process of the inverter,the improved bipolar SPWM modulation strategy is adopted,and all switches realize soft-switching.3.Although the switching devices of the two inverters mentioned in Chapter 2 and Chapter 3 realize soft-switching,some of them realize zero-voltage soft-switching instead of zero-current soft-switching.When IGBT is used as the switching device,the switching loss caused by trailing current cannot be eliminated.In addition,the voltage stress of power switch is higher than the DC bus voltage.In order to further optimize the efficiency of single-phase full-bridge inverter,a novel high efficiency single-phase full bridge zero-current soft-switching resonant pole inverter topology is proposed in Chapter 4.When the auxiliary resonant circuit on the bridge arm participates in the commutation,all switches of the inverter can realize the zero-current soft-switching.When the switching device is IGBT,the realization of true zero-current soft-switching by IGBT can eliminate the switching loss caused by the trailing current,and improve the efficiency of single-phase full bridge inverter with IGBT as the switching device.In addition,before the resonance is triggered,it is not necessary to turn on the auxiliary switch to make the current flowing through the resonance inductance reach the threshold value,which can reduce the on state loss of the auxiliary switch;the power switch voltage involved in the process ofcommutation does not exceed 1/2 of the DC bus voltage.4.In order to apply single-phase full bridge soft switching inverter to small and medium-sized power fields and high-power fields,aiming at the key scientific problem that the main switch in the topology of single-phase full bridge soft switching inverter can not realize true ZVS and true ZCS at the same time,Chapter 5 designs a new single-phase full-bridge soft-switching inverter,whose output end is set with one group and load connected auxiliary circuit.The main switch of the inverter realizes true ZVS and true ZCS by using the auxiliary resonance network.When MOSFET or IGBT is used as the main switch of the inverter,the capacitive switching loss caused by the internal junction capacitance of MOSFET and the switching loss caused by the tailing current of IGBT can be eliminated.MOSFET can be used for medium and small power,and IGBT can be used for high power,so the inverter can be used in medium and small power fields and large power fields.