Tsunehiro Endo

Microcomputer Control for Sensorless Brushless Motor

The microcomputer control of a brushless motor without a shaft position sensor is studied. A method which permits the determination of the permanent magnet rotor position by the back electromotive force (EMF) induced in the stator windings and the starting technique which uses the motor as a synchronous motor at standstill are explained. The motor voltage is chopped by commutator transistors to change the motor speed. The control system consists of a 4-b single-chip microcomputer and two quad-comparators.

Position Sensorless Vector Control of Permanent Magnet Synchronous Motors for Electrical Household Appliances

A position sensorless vector control for a permanent magnet synchronous motor (PMSM) suitable for electrical household appliance motor drives is described in this paper. As a position sensorless control, a simple position estimate equation is presented. The derivation of the equation is described. A simplified vector control method for position sensorless PMSMs is proposed. The proposed method does not employ any automatic speed regulator or automatic current regulator. However, since the motor supply voltage Vd and Vq are calculated on the control rotation axis, the drive performance of our method is almost the same as that of a conventional vector control under a steady-state condition, i.e. constant load and constant speed. Simulation and experimental results are shown. Finally, the authors applied the proposed method to a battery-driven cordless vacuum cleaner. By experiment, a stable drive of 50,000 min-1 was confirmed.

Sensorless Control and PMSM Drive System for Compressor Applications

Sensorless control strategies and a PMSM drive system for compressor applications are presented. The drive system consists of a boost PFC rectifier and a three-phase inverter controlled by one micro-controller-unit (MCU: SH7046, Renesas Tech.). To realize low-cost, high performance, and high reliability, sensorless (current and position) control and a novel vector control strategy are proposed to satisfy the requirements of different compressors. The effectiveness and validity of the proposed control strategies are confirmed by experimental results

Initial rotor position estimation of the interior permanent magnet synchronous motor

A new method of the rotor position estimation is proposed for interior permanent magnet synchronous motors. The proposed method for the initial rotor position estimation consists of two parts: one estimates the rotor position of the magnetic pole; the other determines the direction of the magnetization at the estimated position at the same period. The basic idea and the experimental results are discussed in this paper.

Adaptive back EMF parameter adjustment of simplified vector control for position sensorless permanent magnet synchronous motors

A previously reported simplified vector control for position-sensorless permanent magnet synchronous motors can be affected by errors in setting the motor parameters, because no feedback compensator is used. We examine the effects of errors on the steady-state performance of these motors in this paper. It was found that the current amplitude increases when a parameter error is given and the effect of a back EMF parameter error is especially large. We propose a new back EMF parameter adjustment method based on these results. We determined from our simulation and experimental results that the proposed method can compensate for the current increase caused by the parameter error. A theoretical analysis showed that the proposed method is affected by only the daxis inductance parameter Ld. Therefore, even if there are errors in the other motor parameters, the motor current of the constant load condition is minimized by using the proposed method.

Sensorless vector control with quick response for general purpose inverters

Vector control without using a speed sensor is an ideal method for general purpose induction motor drive inverters. But two problems are encountered when making the methods response quicker. One is to stabilize the hunting at no load with a specific frequency and the other is to build up a design technique for speed control. The authors introduce high stability flux control and show how to design the speed control system. They then give experimental results detailing realization of the quicker response.<<ETX>>

Controlling power factor correction converter for single-phase AC power source without line voltage sensor

As various kinds of domestic electrical goods and office automation equipment have become more widely used, interference from harmonic currents, which are generated from home appliances, has become a problem. Therefore, A power factor correction, PFC, converter has been developed to reduce harmonic currents. In this paper, suitable for a single-phase sinusoidal current input converter. This method provides a sinusoidal input current without using an input current having a standard sinusoidal wave-form. Experiments showed that the method worked effectively. Therefore, we found that it is possible to control harmonic currents and thus improve the efficiency of a PFC converter.