Design And Application Of Low-voltage And High-current Inverter Based On MOSFET

The inverter is born since the1940s, the inverter has experienced rapiddevelopment. Low voltage and high current inverter with its low output voltage,high output current and et al are widely used in low-voltage high-power fields.The main subject in this paper is the study of parallel MOSFET low-voltagehigh-current inverter. After theoretical analysis, simulation and controlexperiments, the design of the rotor field oriented control of induction motor andthe inverter based on the parallel power MOSFET is verified.By induction motor mathematical model coordinate transformation to thetwo-phase synchronous rotating coordinate system, the rotor flux model anddecoupling control is detail analyzed in this paper, and the rotor field orientedindirect control method is used by the space vector pulse width modulation forinduction motor. For the special requirements of low-voltage high-currentinverter, the dead-time compensation strategy is taken. A low voltage highcurrent inverter control system simulation model is built to analyze thewaveforms and low power motor drive performance under the conditions of therated speed and rated load. Simulation results show that the dynamicperformance of the system is preferred by using the rotor field-oriented controlsystem and the motor load capacity is improved, the correctness andeffectiveness of the control strategy are verified.The inverter main circuit is designed based on the principle of the inverter.According to the inverter topology, output requirements and the economicpracticality requirements, the power devices are selected. Power MOSFETcharacteristics and working principle are analyzed by using power MOSFETdevices in parallel scheme. For the phenomenon of MOSFET current imbalancein parallel power, the reasons of current distribution uneven for the parallelpower MOSFET are analyzed, and the system simulation is made for theMOSFET’s parallel current sharing, the balanced current characteristics are.studied. Using the gate resistance compensation solutions to solve the currentimbalance under dynamic switching mode. Since the power MOSFET in themain circuit has the voltage spikes and current spikes during on and off. Buffer circuit is designed by the field of system stability to suppress thegeneration of the power device on and off voltage spike. Through theoreticalanalyze, the mathematical model of buffer circuit is established and the systemsimulation is made for buffer circuit and the main loop circuit, and theoptimization analysis are made for the parameters of the buffer circuit.According to the requirement of the multiple parallel power MOSFET drivercircuit, on the basis of comparison for the common driver chip characterizationanalysis, the driving circuit parameters are calculated, the driver device anddesign reliable drive circuit are selected. The detection circuit and the DSP andCPLD are designed as the core control circuit.Finally, the power circuit, driver circuit, control circuit are debugged, andthe experiment and analysis for the whole system are made. The experimentsresults show that low-voltage high-current inverter system meets the designrequirements, the dynamic performance of the system is pretty well.