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.

A control apparatus to control a vibration motor includes a control unit. The vibration motor includes a vibration body and a contact body contacting the vibration body. The control apparatus applies alternating voltages, generated based on pulse width and frequency of pulse signals, to an electro-mechanical energy conversion element of the vibration motor to cause relative movement between the vibration and contact bodies at a target velocity. The pulse width and the frequency are (i) set such that a first steady velocity exceeds the target velocity, before the relative movement starts, and (ii) changed such that a second steady velocity is less than the first steady velocity, after the relative movement starts, and before an actual velocity at a time of the relative movement exceeds the target velocity. The pulse width or the frequency is controlled such that the relative movement is performed at the target velocity.

A steering control device includes a first control system and a second control system. The first control system includes and a first microcomputer. The first microcomputer is configured to compute a first command value for controlling power supply to a first coil and a second command value for controlling power supply to a second coil. The second control system includes and a second microcomputer. The second microcomputer is configured to compute the first command value and the second command value. The first microcomputer and the second microcomputer are configured to communicate the first command value and the second command value with each other. The cycle of communication between the first microcomputer and the second microcomputer is set to be equal to or shorter than each of the cycles of computations of the first command value and the second command value by the first microcomputer and the second microcomputer.

The invention is a drive system comprising an inverter comprising N arms, each arm including an upper half-arm and a lower half-arm each comprising at least one switching module, a rotary machine connected to the inverter, including a rotor having at least one magnetic element made from a modular magnetization material and a control device which, during magnetization controls the inverter to simultaneously for each one of m arms, set each switching module of the upper half-arm and turned on and each switching module of the lower half-arm is turned off, for each one of k other arms, set each switching module of the upper half-arm to be off and each switching module of the lower half arm to be on, and for each of the remaining arms, set each switching module to be off.

A motor control method for controlling a motor by using an applied AC voltage converted from a DC voltage with an inverter driven by a PWM control, the motor control method includes: calculating a voltage command value for the inverter in order to achieve a desired torque output in the motor; calculating a compensation gain configured to maintain a linear relation between the voltage command value and the applied AC voltage according to a modulation factor indicating a ratio of the applied AC voltage to the DC voltage before and after a conversion in the inverter; limiting the compensation gain using an upper limit value; calculating a compensation voltage command value by multiplying the voltage command value by the limited compensation gain; and applying the applied AC voltage to the motor by driving the inverter using the compensation voltage command value; wherein the upper limit value is set so that the upper limit value become smaller when the modulation factor changes significantly.

An electric motor control apparatus that alternately switches modulation mode between an asynchronous PWM control, which controls an electric motor by fixing a PWM frequency, and a synchronous PWM control, which controls the electric motor by making the PWM frequency proportional to a drive frequency of the electric motor, wherein when switching the modulation mode, a compensation value is calculated based on a state quantity, which correlates with a component in a rotating coordinate system of a voltage applied to the electric motor and is obtained immediately before switching, and the voltage immediately after switching is compensated for by the compensation value.

In a rotating machine control device which controls an alternating current voltage command which is transmitted to an electric power converter, the alternating current voltage command is generated so that 1f component of the phase current may follow a current command. However, when the rotor position information by a position detecting element which detects the position of the rotor of a rotating machine has an error, an offset component is produced in the phase current. A controller includes an offset compensation part which calculates an offset compensation amount, from a detection result of the detection current so that the offset component of the detection current of the current detecting element may be decreased, and performs an addition or subtraction operation of an offset compensation command to the alternating current voltage command which a voltage command generation part outputs.

In some examples, a rotary electric machine includes a stator having a plurality of stator coils arranged in a circular pattern around a central opening configured for receiving a rotor. The rotary electric machine further includes a respective dedicated inverter circuit associated with each respective stator coil. For instance, each respective inverter circuit may be configured to convert direct current power to alternating current power to provide to the respective stator coil.

The present disclosure is constructed on the prior art inverter architecture, a pulse code width modulation (PCWM). This is an open loop motor control system without sensing its rotor position. The present disclosure employs a closed loop method to track the optimum efficiency motor operating point directly. A bench load test is conducted to gather information for an AI type control, which includes both load angle vs. voltage command charts and power factor vs. voltage command charts, with load levels as parameters for certain frequency command ranges. This way, the optimum efficiency motor operating points are generated a priori. The AI type control is mechanized to track the optimum efficiency motor operating points.

A motor drive apparatus that can continue operation within the upper limit of system control even if a voltage drop of an AC power source occurs during operation of a motor used for a hoist or a crane is provided. The inverter control unit of the motor drive apparatus includes a speed reference setting means for setting the rotation speed of the motor, means for detecting a speed deviation between the output of the rotation speed detection means for detecting the rotation speed of the motor and the output of the speed reference setting means, means for controlling the output current of the inverter according to the output of the speed deviation. The speed reference setting means includes a correction circuit for correcting an external speed command given from outside. The correction circuit corrects the external speed command according to a deviation between a detection value of a DC voltage and a first reference value when a voltage drop signal is received from the voltage drop detection means, and makes the corrected speed command as the output of the speed reference setting means.