A motor driving apparatus comprises an inverter circuit for converting an output voltage of a power supply into a three-phase AC and outputting the same to the brushless motor; a rotor position estimation unit for estimating a rotor position of the brushless motor; and an inverter control unit for controlling the inverter circuit so that the brushless motor is driven by a current based on the estimated rotor position. The inverter control unit determines an advance angle of the current supplied to the brushless motor with respect to the estimated rotor position so as to minimize a deviation between a command rpm and an actual rpm. Therefore, it is possible to perform stable weak field control for the brushless motor, independently from the input voltage of the inverter circuit, without using predetermined control variables such as table values.

Motor driving apparatus

An active common mode canceler includes a voltage detection circuit including a plurality of capacitors connected to the output terminals of a power converter for performing power conversion by switching a power semiconductor device and serving to detect a common mode voltage generated when the power semiconductor device is switched, a push-pull type emitter follower circuit which is controlled by the common mode voltage detected by the voltage detection voltage to output a voltage equal in magnitude and opposite in polarity to the common mode voltage, and a common mode transformer having multiple windings and serving to cancel out the common mode voltage by superimposing the voltage output from the emitter follower circuit on the output from the power converter.

Active common mode canceler

DC power supply apparatus includes an input-side rectifier for converting an AC signal from an AC power supply into a DC signal. A DC-to-high-frequency converter converts the DC signal into a high frequency signal in response to a control signal from a control unit. An output-side rectifier converts the high frequency signal into a DC signal and applies it to a load. An input current detector detects an input current flowing through the input-side rectifier and generates a signal representative of the input current. A load current detector detects a load current flowing through the load and generates a signal representative of the load current. The control unit receives the input-current and load-current representative signals, a reference input current signal and a reference load current signal, and provides the DC-to-high-frequency converter with the control signal such that the input-current representative signal can be equal to the reference input current signal and the load-current representative signal can be equal to the reference load current signal.

DC power supply apparatus

A variable speed AC motor control drive system for use in devices such as treadmills and including a module to sense the voltage of the line voltage provided to the system and adjusting the pulse width modulated signals provided to the AC motor in response thereto as well as providing a module for sensing the load placed on the AC motor by monitoring the bus voltage of the system and providing a signal representative of the load such that the duty cycles of the pulse width modulated signals are varied in accordance with the line voltage of the system and the load on the AC motor to maintain the desired motor speed.

Variable speed ac motor drive for treadmill

A control apparatus for controlling a motor of an air conditioner includes a converter (2), having switching means (2a) for improving an input power factor, for converting an AC power to a DC power and an inverter (4) for converting the DC power supplied from the converter to the AC power and supplying to a compressor (3). The output DC voltage of the converter is detected by a DC voltage detecting circuit. An input alternating current is detected by a current detecting circuit (11). A microcomputer (13) for controlling the inverter calculates a current command from data stored on the basis of the detected voltage. The detected current is compared with the current command, an ON percentage of a PWM signal to control the switching means is obtained, and the PWM signal is generated.

Control apparatus for controlling motor of air conditioner

A power converter converts AC input power into AC output power to which a load is connected. This power converter comprises a controller for controlling power converting operation of the power converter, a DC voltage detector for detecting a DC voltage of the DC power to provide a DC voltage signal, a first reference generator for generating a first reference, an output detector for detecting a condition of the AC output power to provide an output condition signal, a second reference generator for generating a second reference in response to the output condition signal, a condition detector for detecting a condition of the AC input power to provide an output condition signal, and a selector for supplying the second reference to the controller when the input condition signal is provided.

Tadao C O Patent Division Mose

Papers

Power converter and method of controlling the same

Leistungskonverter und Steuerverfahren.