一种超级电容储能的双向逆变电路及其控制策略

为解决数控机床加工中意外掉电退刀、伺服单元外接制动电阻产生能耗等问题,提出了一种超级电容储能的双向逆变电路,使得伺服系统在突然断电状态下,储能模块能够继续短时地给数控机床系统供电,完成断电回退的功能。该电路可以提供更高的输出电压和占空比,且在应用中可以取消伺服单元外接制动电阻而将制动能量循环利用,同时提出了相应的控制策略。该电路包括Buck/Boost电路、信号采样电路、PWM逻辑控制电路和互锁驱动电路,通过调节两路互为180°的PWM波占空比及充、放电信号来实现升、降压闭环控制,从而完成能量的双向传递。该拓扑简单、高效,性能稳定,以最少的功率器件实现大功率转换及输出。最后,实验波形验证了所提方案的可靠性。

Energy Storage Bidirectional Inverter Circuit and Control Strategy of a Super Capacitor

In order to solve the problems of unexpected power failure and tool withdrawal in NC machining,and energy consumption caused by external brake resistance of servo unit,a bi-directional inverter circuit of super capacitor energy storage is proposed,which enables the servo system to continue to supply power to the digital control machine system for a short time in the state of sudden power failure and complete the function of power failure and return. The circuit can provide higher output voltage and duty cycle,and can eliminate the external brake resistance of servo unit and recycle the brake energy in application. At the same time,the corresponding control strategy is proposed. The circuit consists of a Buck/Boost circuit,a signal sampling circuit,a PWM logic control circuit and an interlock drive circuit. Through adjusting the duty cycle of two PWM waves and the charging and discharging signals of 180 ° each other,the closed-loop control of raising and lowering voltage is realized,thus the bidirectional transmission of energy is completed. The topology is simple,efficient and stable,with the least power devices to achieve high power conversion and output. Finally,the experimental waveforms verify the reliability of the proposed scheme.