Patent ID: 6268986
Filing Date: 2001-07-31
Classification: H02P,H03K

Abstract:
A motor control unit comprising:a first switching element disposed on a high potential side;a second switching element disposed on a low potential side;a plural phase of switching arms connecting the first switching element and the second switching element together in series and connected to a direct-current power input in parallel to supply an alternating-current motor with alternating-current power from between each switching element of each switching arm;a control computing unit for controlling the switching of each switching element to control the current of the motor; andwherein a semi-conductor element including a P-N junction is disposed near at least one of said switching elements and connected to a constant current circuit, and wherein an overheat prevention means is provided to recognize the temperature of the switching elements by sensing a forward voltage value between the P-N junction of the semi-conductor element and to place the said at least one switching element in an OFF-state when the said at least one switching element is judged to be in an overheat condition based on the recognized temperature of the said at least one switching element.