A protection function of an electronic device is realized with a lower cost. A load drive circuit 102 includes: transistors Qa and Qb for protection of an N-channel type connected between a power source terminal P1 and a power source end P7 for driving; an inverter circuit 14 that drives a load based on an input drive control signal Sd, the inverter circuit 14 being disposed between the power source end P7 for driving and a ground potential; and a booster unit 16 including a capacitor C1 having one terminal connected to an output end of the inverter circuit 14, the booster unit 16 generating, across another terminal of the capacitor C1, a voltage exceeding a power source voltage Vdc, and applying the voltage to control electrodes of the transistors Qa and Qb for protection.

One aspect of a motor control device according to the present invention is a motor control device that controls a motor of an electric pump. The motor control device includes a drive unit that supplies a drive current to the motor; a control unit that controls a rotation speed of the motor by controlling the drive unit based on a rotation speed command value; and a current detection unit that detects the drive current supplied to the motor, and supplies a current detection value indicating a detection result of the drive current to the control unit. The control unit determines whether or not a foreign fluid suction abnormality occurs in the electric pump, based on a first current detection value acquired at a first timing when the rotation speed command value changes from a first command value to a second command value and a second current detection value acquired after the first timing.

In a method for operating a drive system, and drive system, having a rectifier and at least one inverter including an electric motor, the electric motor is connected at the AC-voltage-side connection of the inverter, the DC-voltage-side connection of the inverter is connected via inductance(s) in addition to the line inductance, to the DC-voltage-side connection of the rectifier, a capacitance is connected at the DC-voltage-side connection of the inverter and/or at the DC-voltage-side connection of the rectifier, a series circuit, including a resistor and a controllable semiconductor switch is connected at the DC-voltage-side connection of the inverter and/or at the DC-voltage-side connection of the rectifier, the braking chopper being operated using a single frequency during the particular time span in which the braking chopper is in operation, the frequency, e.g., being set apart from the resonant frequency of the resonant circuit including the inductance or the capacitances.

According to an embodiment, a driving apparatus of a DC brush motor includes: a drive circuit that supplies motor current to a coil of a DC brush motor; and a control circuit configured to: after a predetermined time interval has elapsed since starting-up of the DC brush motor, drop down step-by-step a limit value that sets an upper limit of the motor current; and detect turning into a state where the motor current is limited by the limit value.

According to an embodiment, a driving apparatus of a DC brush motor includes: a drive circuit that supplies motor current to a coil of a DC brush motor; and a control circuit configured to: after a predetermined time interval has elapsed since starting-up of the DC brush motor, drop down step-by-step a limit value that sets an upper limit of the motor current; and detect turning into a state where the motor current is limited by the limit value.

The disclosure provides an inverter device for driving an electric motor, including: an inverter circuit including a plurality of switching elements; and a control circuit controlling the inverter circuit. When a rotation speed of the electric motor is equal to or less than a preset rotation speed threshold and a torque of the electric motor is equal to or greater than a preset torque threshold, the control circuit changes a temperature estimation logic of the switching elements of the inverter circuit.

The disclosure relates to an inverter device, including: an inverter circuit including a plurality of switching elements and a capacitor; an active discharge circuit including a first discharge resistor and a discharge switch connected in series, and connected between a positive electrode and a negative electrode of the capacitor; and a control circuit including a controller respectively connected to the switching elements and the discharge switch. The controller controls the switching elements and the discharge switch. The controller turns on the discharge switch to discharge the capacitor when the controller receives a discharge command from outside the inverter device and an electric motor is rotating.

A motor control system is configured to: determine a current supply limit for an electric motor; receive a current supply of the electric motor; identify one or more motor commands; adjust the one or more motor commands in response to a determination that the current supply is greater than the current supply limit; and selectively control the electric motor using the adjusted one or more motor commands.

An abnormality diagnosis apparatus includes: a friction identification unit that calculates a friction parameter that is a parameter used for calculation of frictional force of a power transmission mechanism connected to a motor; a model torque calculation unit that calculates model torque by performing a process of calculating an estimated value of torque of the motor by using a set value calculated in advance and the friction parameter; and an abnormality determination unit that diagnoses whether the power transmission mechanism is abnormal, on the basis of a result of comparison between the model torque and a motor torque detected by a motor torque detection unit.

An abnormality diagnosis apparatus includes: a friction identification unit that calculates a friction parameter that is a parameter used for calculation of frictional force of a power transmission mechanism connected to a motor; a model torque calculation unit that calculates model torque by performing a process of calculating an estimated value of torque of the motor by using a set value calculated in advance and the friction parameter; and an abnormality determination unit that diagnoses whether the power transmission mechanism is abnormal, on the basis of a result of comparison between the model torque and a motor torque detected by a motor torque detection unit.