Kabushiki Kaisha Toshiba

Atsuyuki Hiruma

Masao Isshiki

Masao Ozu

Michika Uesugi

Naoki Oomura

Shingo Ikawa

Eiji Kuwahara

Toru Kubo

Harunobu Nukushina

Atsushi Nagasawa

Kazuhiko Akiyama

Takao Hoshi

Nobuo Kawai

Kazuo Mochizuki

Yoshiaki Nagaoka

Tohru Kubo

Oserojouin Watabiki

Kazuhito Ono

Hiroyuki Ota

A method and apparatus for controlling a brushless DC motor which has a permanent magnet rotor and a 3-phase stator winding for applying a rotating magnetic field to the permanent magnet rotor. A specified reference voltage is compared with the stator winding terminal voltages for each phase. The rotor position is detected from the output of these comparison circuits based on the induced voltages generated in the stator windings which are not conducting when the motor is rotated. The stator windings which conduct current are controlled in response. Furthermore, a specific conduction pattern is supplied to each stator winding when the rotor is stopped, and a reference output determined for the conduction pattern is compared with the output of the comparison circuits when the stator windings are conducting. Abnormalities are detected based on the comparison results of the comparison circuit.

Method and apparatus for controlling a brushless DC motor that indicates

In a direct-current power supply system, an alternating current outputted from an AC power supply is converted by a second diode bridge circuit into a direct current. The direct current is smoothed by voltage doubler capacitors and a smoothing capacitor. A reactor is inserted into an input side of the second diode bridge in series. Detecting circuit is operatively connected to the AC power supply for detecting a zero-crossing point. When the zero-crossing point is detected by the detecting circuit, control means is adapted to firstly switch a switching element on for a first predetermined period of time and, after a predetermined delay period of time has passed since the switching element is firstly switched on, adapted to secondly switch the switching element on for a second predetermined period of time. While the switching element is firstly and secondly switched on, a first diode bridge circuit means is adapted to short-circuit the AC power supply through the reactor so that the AC is forced to flow through the reactor. The rectification means, the short circuit means and the switching element are packaged in one package so that the rectification means, the short circuit means and the switching means are integrated into the one package as one semiconductor module.

Direct-current power supply system and air conditioner

Method and apparatus for controlling a brushless DC motor

When power is sequentially supplied to the phase coils of a brushless DC motor, the rotor of the brushless DC motor is rotated. At this time, a voltage is induced in one of the phase coils to which power is not supplied. The rotational position of the rotor is detected from the induced voltage. The switching timing of power supply to the phase coils is determined in accordance with the detected rotational position. When a service operation mode switch is operated, a service operation is executed, and power supply to the respective phase coils is forcibly switched at a predetermined frequency. A failure can be diagnosed during this service operation.

Drive apparatus for brushless DC motor and failure diagnosing method for

A refrigeration cycle has a compressor, an outdoor rotary-type heat exchanger, a motor-operated expansion valve, and an indoor rotary-type heat exchanger which are sequentially connected to each other to circulate a refrigerant. A tank is set in a connected state or a non-connected state with respect to a refrigerant discharge side of the compressor. A detector detects at least a pressure at one side of each of the exchangers. A first controller sets the tank in a non-connected state when a normal operation of an air conditioner is to be started, and controls the capacity of the compressor, the rotational speed of the exchangers, and the opening degree of the valve in accordance with an air-conditioning load, thereby performing the normal operation of the air conditioner. A second controller causes the compressor to keep operating at a predetermined capacity until a detection pressure from the detector coincides with a preset value, when the air conditioner is to be stopped, and sets the tank in a connected state while controlling the valve to a predetermined opening degree, thereby recovering a refrigerant in the tank. A third controller rotates the exchangers at a predetermined speed when the air conditioner is to be started, and sets the tank in a connected state while controlling the valve to a predetermined opening degree, thereby filling the refrigerant in the exchangers from the tank.

Air conditioner using rotary-type heat exchangers

There are provided a resistor having a low resistance and inserted in a d.c. current path of which an overcurrent is detected, and a bias circuit for generating substantially a constant d.c. voltage. A voltage obtained by superposing a voltage across the resistor upon a voltage supplied from the bias circuit is monitored. When the monitored voltage reaches a predetermined threshold value, an overcurrent detection signal is generated by means of a photocoupler.

Overcurrent detector

There is disclosed a current control apparatus comprising first controllers adapted for detecting an overall or total load current to calculate distribution values for distributing a current margin with respect to an overall or total current limit value to respective air-conditioners; and second controllers adapted for respectively controlling air-conditioners so as not to exceed individual current limit values, and for carrying out an incremental correction of individual current limit values in accordance with distribution values calculated by the first controllers.

Current control apparatus for air-conditioning system

Growing community of inventors

Fuji, Japan

Atsuyuki Hiruma