【摘要】 功率放大器与电磁铁作为电磁轴承系统的执行环节,是影响电磁轴承系统性能及体积的关键部件。为了减小功率损耗和易于实现系统控制,提出了一种带有电流负反馈的双极型PWM开关功率放大器,驱动脉宽信号由DSP产生,占空比可在线调节。通过对线圈和功放进行具体建模,并对其基本特性进行理论分析与仿真实验;为提高系统高频动态特性,提出了低偏置电流工作方式。研究结果表明,这种功放结构和工作方式对电磁轴承结构设计和控制器设计具有重大的指导意义和参考价值。更多还原

【Abstract】 The actuator consists of power amplifier and electromagnet that is the key part which influence the performance and volume of Electromagnetic Bearing (EMB) system. In this work, a switching power amplifier with current negative feedback is introduced in order to reduce the current ripple for better control.It uses dipole structure. The PWM driving signals are produced by Digital Signal Processor (DSP), and the duty-cycle of driving pulse can be modified continuously on-line. The power amplifier model at different frequency channel is built respectively according to the amplitude response characteristics of transfer function. The low-bias current control method is proposed in order to improve system high frequency dynamic performance. Theoretical analysis, computer simulation and experiments were used to verify them. The results show that low-bias current control method can reduce power loss effectively and achieve system control easily.更多还原