A control apparatus calculates a total loss change amount that is a power loss change amount of a motor control system including respective power loss change amounts of a converter, an inverter, and a motor of the motor control system. Based on the total loss change amount, during a correction-allowed period that is a period during which square wave control is performed, the control apparatus performs correction to decrease a current output voltage command value of the converter when the current output voltage command value is determined to be greater than the output voltage of the converter at which actual total power loss change amount becomes minimum. When the current output voltage command value is determined to be less than the output voltage of the converter at which actual total power loss change amount becomes minimum, the control apparatus performs correction to increase the current output voltage command value.

An energy-efficient and accurate torque control system and method for multiphase nonsinusoidal PMSM with or without open-circuited phase(s) under time-varying torque and speed conditions is based on orthogonally decomposing a phase voltage vector into two components, which become primary and secondary control inputs for torque control and energy minimizer control. The primary control system includes nonlinear feedback from measured phase currents, motor angle, motor speed, and instantaneous value of reference torque and a signature vector indicating which phase(s) is/are open-circuited to establish a first-order linear relationship between reference and generated torques. The secondary control system includes an estimator to estimate a system costate from measured phase currents, motor angle, motor speed, and instantaneous value of reference torque and the signature vector and a linear programming module with equality/inequality constraints to calculate the secondary voltage input to optimally align the overall phase voltage for maximum efficiency without saturating the inverter voltage.

A motor driving device that is a device for driving a motor including stator windings, includes: a connection switching unit that includes relays as mechanical switches connected to the stator windings and excitation coils opening or closing the relays by being energized or non-energized with excitation current and switches connection condition of the stator windings to either of first connection condition (star connection) and second connection condition (delta connection) different from the first connection condition by opening or closing the relays; and an inverter that supplies AC drive voltages to the stator windings.

The present invention relates to a speed control system for hermetic compressors of the variable speed type, which uses a PMSM motor, containing a strategy for optimization, or minimization, of the electric current. Once the minimum current has been defined to meet a given demand for torque, it is applied to the hermetic compressor motor, which will operate at the maximum efficiency point for each load point.

The present invention relates to a speed control system for hermetic compressors of the variable speed type, which uses a PMSM motor, containing a strategy for optimization, or minimization, of the electric current. Once the minimum current has been defined to meet a given demand for torque, it is applied to the hermetic compressor motor, which will operate at the maximum efficiency point for each load point.

A method for controlling an asynchronous induction motor, a control device for implementing the method, a motor system including the control device, and a computer-readable storage medium on which a computer program for implementing the method is stored. The method for controlling the asynchronous induction motor includes: A. determining a target value of d-axis current according to a target value of q-axis current of the asynchronous induction motor; B. determining a correction value of the target value of the d-axis current based on q-axis voltage and d-axis voltage of the asynchronous induction motor; and C. determining target values of the d-axis voltage and the q-axis voltage of the asynchronous induction motor based on the correction value of the target value of the d-axis current and the target value of the q-axis current.

In a method for determining a flux of an asynchronous machine, the flux is adjusted according to a loss of the asynchronous machine. Therefore, an apparatus for determining the flux of the asynchronous machine is provided with a model for calculating a loss of the asynchronous machine according to the flux of the asynchronous machine. A selection facility selects a flux according to the loss.

In a method for determining a flux of an asynchronous machine, the flux is adjusted according to a loss of the asynchronous machine. Therefore, an apparatus for determining the flux of the asynchronous machine is provided with a model for calculating a loss of the asynchronous machine according to the flux of the asynchronous machine. A selection facility selects a flux according to the loss.

To provide a controller for rotary electric machine apparatus which can calculate the voltage command value of the converter which reduces power loss with good accuracy, in the case where the normal modulation control and the overmodulation control are switched and performed. A controller for rotary electric machine apparatus sets a system voltage that power loss becomes the minimum as the converter voltage command value, based on a power loss characteristics of the normal modulation control which is a power loss characteristics of at least the inverter with respect to the system voltage in performing the normal modulation control, and a power loss characteristics of the overmodulation control which is a power loss characteristics of at least the inverter with respect to the system voltage in performing the overmodulation control.

To provide a controller for rotary electric machine apparatus which can calculate the voltage command value of the converter which reduces power loss with good accuracy, in the case where the normal modulation control and the overmodulation control are switched and performed. A controller for rotary electric machine apparatus sets a system voltage that power loss becomes the minimum as the converter voltage command value, based on a power loss characteristics of the normal modulation control which is a power loss characteristics of at least the inverter with respect to the system voltage in performing the normal modulation control, and a power loss characteristics of the overmodulation control which is a power loss characteristics of at least the inverter with respect to the system voltage in performing the overmodulation control.