CONTROL DEVICE FOR SINGLE-PHASE INDUCTION MOTOR AND AIR CONDITIONER USING THE SAME

PROBLEM TO BE SOLVED: To provide a controller for a single-phase induction motor that safely performs the switching operation from an operation based on a commercial power source to an operation based on an inverter without temporarily stopping a motor.SOLUTION: A controller for a single-phase induction motor that has an inverter 5 for applying an AC voltage having a frequency equal to a commercial power source frequency or less and a phase difference of substantially 90 degrees to a primary winding 7 and an auxiliary winding 8, first opening/closing parts (SW1a, SW1b) connected to a commercial power source 1 and the primary winding 7 so as to form a closed circuit together with a commercial power source 1 and the primary winding 7, and a second opening/closing part (SW2) connected to the commercial power source 1 and the auxiliary winding 8 so as to form a closed circuit together with the commercial power source 1 and the auxiliary winding 8. When a first driving mode in which the opening/closing parts are set to ON-state, the inverter 5 is set to OFF-state, and a single-phase induction motor 9 is driven by the commercial power source 1 is switched to a second driving mode in which the opening/closing parts are set to ON and the single-phase induction motor 9 is driven by the inverter 5, the inverter 5 is kept to OFF-state while the contact points of the opening/closing parts are set to ON-state. 【課題】単相誘導電動機の制御装置において、商用電源による運転からインバータによる運転への切替を、電動機をいったん停止させることなく、かつ安全に行う。【解決手段】主巻線７および補助巻線８に、商用電源周波数以下の周波数でかつ、概略９０度の位相差を有する交流電圧を印加するインバータ５と、商用電源１および主巻線７と合わせて閉回路を形成するように接続された第１の開閉部（ＳＷ１ａ、ＳＷ１ｂ）と、商用電源１および補助巻線８と合わせて閉回路を形成するように、互いに直列に接続された第２の開閉部（ＳＷ２）とを備えて、前記開閉部をともにオン、インバータ５をオフ状態として、商用電源１により単相誘導電動機９を駆動する第１の駆動モードから、前記開閉部をともにオフとし、インバータ５によって単相誘導電動機９を駆動する第２の駆動モードに切り替える際、前記開閉部の接点がオン状態である間、インバータ５をオフ状態に保つ。【選択図】図１