具有延时补偿的磁悬浮轴承开关功率放大器数字单周期控制

Digital One-Cycle Control Algorithm with Compensation of Time Delay for Switching Power Amplifier in Magnetic Suspension Bearings

在磁悬浮轴承的开关功率放大器系统中,采用数字单周期控制算法具有算法简单、易实现、响应速度快等优点,但传统的单周期控制算法存在控制延时的缺点,会影响系统的稳定性以及功率放大器带宽。该文在考虑磁悬浮轴承线圈电阻压降的情况下,分析了数字单周期控制算法的原理,精确了算法的数学模型;结合算法原理对磁悬浮轴承控制系统的延时进行了估算,并推导了两种延时补偿模型,对延时补偿前、后的数字单周期控制算法进行了仿真与实验。结果表明:精确算法模型后的单周期控制能使实际电流波形跟踪给定波形,验证了算法的可行性;两种延时补偿模型均能使电流跟踪波形与给定波形相比基本无相位差,验证了延时补偿模型的有效性;补偿模型Ⅱ跟踪效果更佳,验证了补偿模型Ⅱ的优越性。

Adopted in switching power amplifier for magnetic suspension bearings, digital one-cycle control has the advantages of simple structure, easy realization and rapid response. Time delay is one of the major disadvantages of the traditional digital one-cycle control, which will influence the system stability. The principle of one-cycle control was analyzed with the consideration of resistance voltage drop for more precise control. Time delay was estimated according to the digital control system. Two models with compensation of time delay were derived. Simulation and experiments were carried out. Simulation and experimental results show that the current can follow the reference with the precise algorithm, proving its feasibility. With compensation of time delay, there is hardly any phase shift between the coil current and reference, which verifies the effectiveness of the proposed models. The tracking waveform is better with the model II, demonstrating its superiority.