异步电机瞬态激励无传感器磁场定向控制研究

在分析异步电动机瞬态激励数学模型的基础上,提出电流瞬态响应二次测量结果相叠加获得转子位置信息的技术.该技术利用电压源逆变器产生的驱动信号作为激励信号,通过检测PWM逆变器馈电时电机绕组电流瞬态变化来辨识静止状态到较高速时的电机转子信息.采用仿真手段分析逆变器死区时间及电子元件压降的影响,并给出了相应的补偿方式,边界条件为:电机理想对称,逆变器为理想状态.仿真研究表明:由于死区时间t0的影响,电流瞬态响应发生变化,导致工作点漂移.针对3kW/380V/50Hz异步电机进行了实验,实测结果验证了该方法实现无传感器磁场定向控制转子位置检测的可行性和优越性.

Study on the Transient Excitation of Asynchronous Machine with Sensorless Field Oriented Control

Based on analysis of the mathematic model for an induction machine excited by transient pulses,a method was proposed to obtain the rotor position information by superposing twice subtraction of current transient samples.The output of voltage-source inverter were taken as tested pulses to inject into the phase windings,and the current transient changes of the machine due to stator voltage test pulses were evaluated.Thus rotor information,from its standstill condition to high speed condition,were obtained and further identified by measuring the current transient slope resulting from the inverter PWM modulation.The disturbing of the interlock dead time and some voltage drops were studied by simulations assuming an ideal inverter and an ideal linear machine with no losses.The comparisons were made of the simulated waves of current transient change caused by either exciting pulses with dead time or the ones without dead time.It was found that the main influent of the dead time was a shift in the operating point of the machine.A compensation method was introduced to reduce disturbing harmonics.The feasibility and superiority of the proposed method was verified through the experimental research concerning an induction machine with parameters of 3 kW,380 V,and 50 Hz.