毕业论文外文翻译--基于dsp高速无刷直流电机控制使用直流环节电压控制

毕业论文外文翻译--基于dsp高速无刷直流电机控制使用直流环节电压控制内容摘要：

onfiguration [1]. In particular, for a motor built in a pletely sealed pressor, a shaft sensor is difficult to apply due to the degradation of the sensor reliability in high temperature and the need for extra lead wires. Furthermore, these sensors, particularly Hall sensors, are temperature sensitive, limiting the operation of the motor to below about 75176。 C [1]. An absolute sensor is generally speed limited to about 6000 rpm and a resolver needs a special external circuit. Also, the sensor accuracy may be affected by the accuracy of the mounting. To overe these drawbacks, sensorless control techniques for a BLDC motor have been proposed [1_5]. There are two categories of position detection schemes, namely, the method using the back EMF of the motor [2] and themethod based on the detection of the conducting interval of freewheeling diodes [3]. In the existing sensorless control schemes, the PWM technique is generally used for a speed control. However, since the PWM and inverter mutation cannot be performed independently, a signi cant mutation delay may exist in a high speed region. Recently, to improve the drive effciency and provide the desired current waveform, a sensorless control scheme using a quasicurrent source inverter has been proposed [6]. Such a circuit arrangement is known as a variable DC link inverter [7].In this scheme, the inverter frequency is controlled to supply threephase rectangular current with a pulse width of 120176。 and the motor voltage for the speed control is regulated by using a stepdown chopper acting as a buck converter. However, some advantages of the DClink voltage control scheme over the conventional 2phase PWM scheme in the high speed sensorless control have not been addressed. This article presents a DSPbased high speed sensorless control for a BLDC motor 3 using a DC link voltage control scheme. By driving the BLDC motor at high speed, the overall drive system can have a small size and a light weight at the same power rating. To control the BLDC motor at high speed without a shaft sensor, a DSPbased controller is developed using TMS320C240. Using the DC link voltage control scheme, the inverter is operated with the squarewave of 120176。 conduction interval and the speed control is achieved by regulating the DC link input voltage of inverter through the chopper. By using this technique, since the voltage control and mutation can be achieved independently, the mutating delay such as in the conventional 2phase excitation PWM methods does not exist even in a high speed region, which will be discussed in the later section. The rotor position information is detected using the back EMF from the terminal voltages of the motor and the switching sequence of the inverter [2]. The sensed back EMF is used in the integration and parison circuits to obtain the mutation signals. The detected mutation signals are used to apply the proper next sequence of inverter and obtain the rotational speed within a DSP. The calculated speed is controlled by a digital PI control algorithm and the controller output is applied to the chopper. The practical implementation issues concerning the mutation delay of the 2phase excitation PWM schemes at high。