ELECTRIC MOTOR DRIVING DEVICE

PROBLEM TO BE SOLVED: To provide an electric motor driving device that can avoid destabilization of control of a motor caused by voltage saturation by accurately determining the voltage saturation, thereby enabling an excellent driving operation from a low-speed rotation area to a high-speed rotation area.SOLUTION: An electric motor driving device has an output duty count part 21 for counting a frequency when the output duty of an inverter is equal to each predetermined rate during a fixed period, a percentage content calculator 22 for calculating the rate of the frequency for the duty of 100% to the whole frequency, a voltage saturation determination reference value setting part 25 for storing a predetermined voltage saturation determination reference value, a voltage saturation determining part 23 for determining the voltage saturation that the percentage content is larger than the predetermined voltage saturation determination reference value, and a voltage saturation avoiding controller 24 for executing at least one of increase of the advance angle of an electric motor and a deceleration instruction of the electric motor till the percentage content decreases to be lower than the predetermined voltage saturation determination reference value when the percentage content is larger than the predetermined voltage saturation determination reference value, thereby avoiding the voltage saturation. 【課題】電圧飽和を正確に判断することで、電圧飽和に起因するモータの制御不安定化を回避し、低速回転域から高速回転域まで良質な駆動を可能にする。【解決手段】ある一定の期間における、インバータの出力デューティが所定の各割合のときの回数をカウントする出力デューティカウント部２１と、全体の回数に対して、デューティが１００％の回数の割合を算出する含有率算出部２２と、所定の電圧飽和判断基準値を記憶する電圧飽和判断基準値設定部２５と、含有率が所定の電圧飽和判断基準値より大きい場合に電圧飽和と判断する電圧飽和判断部２３と、含有率が所定の電圧飽和判断基準値より大きい場合に、含有率が所定の電圧飽和判断基準値より小さくなるまで、電動機の進角を増加させる、もしくは電動機の速度減速指示のうち、少なくとも一方を実施することで電圧飽和を回避する電圧飽和回避制御部２４を備える。【選択図】図１