Abstract: The present invention supplies a position detection circuit, and a motor controller, that can not only obtain rotor position detection signals properly over the entire PWM control region, but also obtain these signals properly during PAM control. In a brushless motor controller based on the present invention to detect the magnetic pole position of the stator in the motor in accordance with the stator coil terminal voltages of multiple phases and control the energization of the stator coils, the comparison result information signal, after being obtained through comparison between the detected voltage values corresponding to the foregoing terminal voltages, and a reference voltage value, is directly entered into control circuits, then the position of the rotor in the motor is properly detected immediately after power-on switching, without a rotor position detection inhibition time interval being provided, and the motor is controlled properly.

Abstract: A motor drive apparatus and an air-conditioner using the motor control apparatus has a feature which allows it to gradually increase a dc voltage value to a predetermined value when starting the switching operation of a chopper circuit by dc voltage control thereof, and when stopping the switching operation of the chopper circuit to be able to gradually decrease the dc voltage value to a predetermined value. Further, the dc voltage command value is adjusted so as to make it possible to maintain a preferred value of dc voltage. Thereby, fluctuation in the number of revolutions of the motor can be prevented even if the converter is started or stopped while the motor is operating, thereby allowing the motor drive apparatus and air-conditioner using the motor control apparatus of the invention to be operated at their maximum capacities.

Abstract: For achieving an air conditioner being applicable to various a-c source voltages in common and operative with high power factor by suppressing generation of high harmonics, an a-c source voltage from an a-c electric power source 1 is rectified in full-wave by a rectifier 2, and a d-c source voltage Ed of an inverter 13 is obtained by being charged in a condenser 5. Here, there are a-c source voltages of 100 V and 200 V, and a divided voltage Ed1 of the d-c voltage of the condenser 5 is selected when the a-c source voltage is 100 V, a divided voltage Ed2 (here, Ed1>Ed1) of the d-c voltage of the condenser 5 is selected when the a-c source voltage is 200 V, respectively by an exchange switch 18, and is used as a d-c voltage Ed' for controlling on and off of a switch element 6.