Abstract: A motor driving device includes a motor driving circuit, an element temperature sensor, a control circuit, an ambient-temperature estimator, and an overheat protection processor. The motor driving circuit has a plurality of switching elements. The element temperature sensor is configured to detect a temperature of each of the switching elements. The ambient-temperature estimator is configured to estimate an ambient temperature around the control circuit based on a temperature of at least one of the switching elements detected by the element temperature sensor if the at least one of the switching elements is not performing the switching operation. The overheat protection processor is configured to execute a first overheat protection process to protect the control circuit from overheating if the ambient temperature around the control circuit estimated by the ambient-temperature estimator exceeds a first overheat criterion temperature.

Abstract: A motor driving device includes a motor driving circuit, an element temperature sensor, a control circuit, an ambient-temperature estimator, and an overheat protection processor. The motor driving circuit has a plurality of switching elements. The element temperature sensor is configured to detect a temperature of each of the switching elements. The ambient-temperature estimator is configured to estimate an ambient temperature around the control circuit based on a temperature of at least one of the switching elements detected by the element temperature sensor if the at least one of the switching elements is not performing the switching operation. The overheat protection processor is configured to execute a first overheat protection process to protect the control circuit from overheating if the ambient temperature around the control circuit estimated by the ambient-temperature estimator exceeds a first overheat criterion temperature.

Abstract: There is provided a control system for an electric motor to which electric power is supplied from a DC power supply via a multi-phase inverter, the multi-phase inverter including switch units respectively provided on a positive side and a negative side of arms corresponding to respective phases, each switch unit including a switching element and a reflux diode connected in parallel thereto. The control system comprises a phase current detection unit for detecting phase currents which flow between the inverter and the electric motor, a DC component acquiring unit for acquiring DC components of the respective phase currents, and a short-circuiting determination unit for determining that a short-circuit failure occurs in the inverter when at least one of the DC components of the phase currents acquired by the DC component acquiring unit exceeds a threshold. Consequently, the short-circuit failure of the inverter can be detected even though the control of the electric motor is stopped.

Abstract: There is provided a control system for an electric motor to which electric power is supplied from a DC power supply via a multi-phase inverter, the multi-phase inverter including switch units respectively provided on a positive side and a negative side of arms corresponding to respective phases, each switch unit including a switching element and a reflux diode connected in parallel thereto. The control system comprises a phase current detection unit for detecting phase currents which flow between the inverter and the electric motor, a DC component acquiring unit for acquiring DC components of the respective phase currents, and a short-circuiting determination unit for determining that a short-circuit failure occurs in the inverter when at least one of the DC components of the phase currents acquired by the DC component acquiring unit exceeds a threshold. Consequently, the short-circuit failure of the inverter can be detected even though the control of the electric motor is stopped.

Abstract: Disclosed herein is a capacitor mounting type inverter unit having a cooling block, an inverter including a plurality of phases of switching circuits provided on the cooling block, and a smoothing capacitor. The inverter unit includes a cover having a first recess for accommodating the inverter and a second recess for accommodating the smoothing capacitor. The second recess has a depth larger than that of the first recess. The second recess is filled with resin in the condition where the smoothing capacitor is accommodated in the second recess.

Abstract: Disclosed herein is a capacitor mounting type inverter unit having a cooling block, an inverter including a plurality of phases of switching circuits provided on the cooling block, and a smoothing capacitor. The inverter unit includes a cover having a first recess for accommodating the inverter and a second recess for accommodating the smoothing capacitor. The second recess has a depth larger than that of the first recess. The second recess is filled with resin in the condition where the smoothing capacitor is accommodated in the second recess.

Abstract: In an electric vehicle in which a motor is driven using the electric power of a battery, and a PWM controller controls an inverter mounted between the battery and the motor. The frequency of the PWM control means is usually set higher than an audio frequency, in order to decrease the switching noise of the inverter. Motor operational state detecting devices detect when the motor is at low speed and high-load operational state, and if there is a possibility that switching elements of the inverter may be over-heated, the frequency of the PWM controller is decreased by a frequency changing device, thereby preventing damage to the switching elements of the inverter due to the over-heating.