Eps High Frequency Inverter Technology And Control Strategies

Inverter is a kernel part of Emergency Power Supply.Traditional inverter which applied to EPS uses analog circuits as control method,and achieves voltage matching with low-frequency transformer.Therefore,it often leads a series of problems to EPS Products,such as larger volume,more expensive,extra audio noise,lower efficiency, poorer reliability,and difficult to realize complex algorithms and intelligent management.Aiming at above problems,this paper focuses on theory research, simulation validation and prototype experiment for inverter technology and its control strategy in EPS.High-frequency link technology has great advantage on inverter efficiency improvement,volume reduction,reliability enhancement.DC(low voltage)/AC(low voltage high frequency SPWM pulse)/AC(high voltage and low frequency sine wave) is applied as high-frequency inverter solution in this paper.Inverter in this solution has only two levels of power conversion by well combining the high-frequency pulses and basic SPWM wave,in order to improve efficiency and reliability of inverter.At the meanwhile,circuit topology is improved for implementation of dual-use with inverter/ charger functions,reducing the scale of hardware circuit to make it more applicable to the EPS system.Using digital control to replace analog control is the development trend of inverter technology.TMS320LF2407 is used as kernel control chip to realize digital programming for third-order SPWM wave producing algorithm and PID control strategy,to improve steady state accuracy of output voltage and performance of dynamic response.Based on theory study,prototype is developed,and experiment is implemented. Results show that the hardware and software design of inverter is reasonable,and the performance of EPS is improved greatly.Because EPS is used in special occasions of fire emergency,inverter load is characterize as non-linear and complex.So,theory of closed-loop control strategy for inverter output voltage is researched further in this paper.Fuzzy PID control strategy is used to amend PID parameters online.Through this way,waveform distortion and harmonic components of the inverter output voltage can be reduced effectively,in order to increase robustness of the inverter output voltage and reduce dependency of EPS on loads.The theory research and practice on high-frequency inverter technology and its control strategy of ESP system in this paper,not only playing a key role on performance improvement for EPS product,but also proposing as a reference how to apply high-frequency inverter in other areas.