基于移相调功的三电平超音频感应加热电源

多电平逆变器用于高电压大功率场合,可有效解决单只功率开关器件电压及电流定额受限的难题.基于这一优点,设计了适用于负载串联谐振的三电平感应加热逆变电源,给出了三电平逆变电源的拓扑结构,并采用PS-PWM(移相-脉宽调制)输出功率控制策略,在有效控制和调节输出功率的同时,改善了输出电压与电流波形的质量.采用PS-PWM控制方法,在器件额定电压确定时可提高1倍逆变器容量,且输出电压和电流的谐波也明显减少.利用PSPICE对25 kHz、540Vdc的超音频感应加热逆变电源的实际工况进行了仿真,理论分析与仿真结果验证了文中提出的三电平逆变器拓扑结构及功率控制策略的正确与合理性.

Research on Three-Level Ultrasonic-Induction-Heating Power Based on Phase-Shifted Power Control

A multilevel inverter is widely used in the cases of higher voltage and larger power capacity.The inverter is usually applied to overcome the shortcomings of the rated voltage or/and current being limited in single power electronic component.Therefore,its capacity is limited.For enhancing the output power and improving output waveform qualities of voltage and current,a novel three-level inverter with serial-resonant load used in an induction heating power is introduced in this paper.To regulate output power of the load-resonant induction heating supply,the control strategy based on PS-PWM(Phase-Shifted PWM) and the control method of the proposed three-level inverter are also applied.In this way,the inverter capacity is easily enhanced to two times with the same rated voltage components as well as the harmonics of output voltage and current are obviously reduced by the novel PS-PWM control strategy.The theoretic analysis and the simulation results,using Pspice to simulate the practical operation of induction-heating power inverter(25 kHz,540 Vdc),show the rationality and validity of the proposed three-level inverter topology and its control strategy.