A permanent-magnet-synchronous electric motor control device includes: a reference voltage value calculation unit for calculating a reference voltage value; an output voltage value calculation unit for calculating an output voltage value on the basis of a voltage command; a current weakening command calculation unit for calculating a current weakening command on the basis of the reference voltage value and the output voltage value; a voltage command calculation unit for calculating the voltage command on the basis of the current weakening command; and a power converter for supplying power to a permanent-magnet-synchronous electric motor on the basis of the voltage command. The current weakening command calculation unit calculates the current weakening command in which a high-frequency component is amplified on the basis of the difference between the reference voltage value and the output voltage value.

A control method of an electric machine is described, including a first step of detecting the angular position of a rotor of the electric machine; a second step of detecting the values of the alternate current next to at least two phases of the input current to the electric machine; a third step of detecting the values of voltage and direct current supplied as input to the inverter by the electric supply means; a fourth step of estimating the torque supplied by the electric machine performed by processing data detected in the first and second step; a fifth step of computing the torque supplied by the electric machine performed by processing data detected in the third and first step; a sixth step of comparing the value of the computed torque and the value of the estimated torque; a control system and a motor comprising such system are further described.

A motor controller includes a rectifier module, an inverter circuit, an energy storage capacitor C1, a DC inductor L1, a microprocessor, and a lightning protection and surge protection circuit. The rectifier module includes an output end connected to the energy storage capacitor C1 to charge the energy storage capacitor C1; two ends of the energy storage capacitor C1 are connected to the inverter circuit to supply power to the energy storage capacitor C1. The DC inductor L1 is in series connection between a positive output end A of the rectifier module and a positive end B of the energy storage capacitor C1. The lightning protection and surge protection circuit is disposed between the rectifier module and the energy storage capacitor C1. The lightning protection and surge protection circuit includes a differential mode protection circuit and a primary common mode protection circuit.

A determination device includes: an acquiring unit configured to acquire an electric current value detected in a state where electric current is flown in a plurality of directions in an electric motor so that torques produced in the electric motor are balanced; and a determining unit configured to perform disconnection determination of determining whether or not there is a disconnection based on the electric current value acquired by the acquiring unit.

A power tool with a direct current, DC, power source comprising a controller for controlling a driver circuit driving a brushless motor in a power tool, the driver circuit being coupled to a direct current, DC, power source and including a first switching element pair coupled to a first phase winding of the brushless motor and a second switching element pair coupled to a second phase winding of the brushless motor; and the controller being arranged to alternately switch a first switching element of the first switching element pair and a second switching element of the second switching element pair, wherein the first switching element and the second switching elements are coupled to a respective terminal of the DC power source. A power tool comprising such a controller, and a method of controlling a driver circuit driving a brushless motor in a power tool.

A method of controlling operation of an electric machine includes: determining a voltage-based torque limit based on a voltage constraint of a direct current (DC) bus supplying power to an inverter for powering the electric machine; determining a motor current-based torque limit based on a motor current limit; determining a final torque limit based on the voltage-based torque limit and the motor current-based torque limit; determining a limited command torque based on a torque command and the final torque limit; determining an initial current command corresponding to the inverter satisfying a regenerative current limit of the DC bus; and calculating a final current command based on, at least, the limited command torque and the initial current command. The method includes the final current command exceeding the initial current command to cause the electric machine to produce a torque corresponding to the limited torque command.

An electrical system configured to control an electrically-excited electric motor, including: an inverter configured to supply alternating current (AC) electrical power to the electrically-excited electric motor; the electrically-excited electric motor, including: a rotor having a rotor winding; and a stator having a stator winding; the stator winding is electrically connected to the inverter and the rotor winding is electrically connected to the inverter such that the stator winding receives an electrical current from the inverter and supplies a direct current (DC) component to the rotor.

This present disclosure provides a compressor and a refrigeration device having the compressor. The refrigeration device has a coupling assembly and a frequency converter connected to one end of the coupling assembly. The compressor has a first shell and a permanent magnet motor. The permanent magnet motor is set in the first shell and connected to the other end of the coupling assembly. By designing the relevant parameters of the motor of the compressor, the efficiency of the motor and the compressor can be improved.

Conventionally, there is a problem that switching loss of an inverter increases in a case where a change such as improvement in a switching frequency is involved. The battery voltage E and the torque command T* are input to the first current command generation unit 111. The battery voltage E, the torque command T*, and a voltage utilization rate obtained by dividing a line voltage effective value by a battery voltage (DC voltage) are input to a second current command generation unit 112. A magnet temperature Tmag of a rotor magnet is input to a current command selection unit 113, and a current command output from the first current command generation unit 111 is selected in normal operation, and the second current command generation unit 112 is selected in a case where the magnet temperature exceeds a predetermined value. The second current command generation unit 112 is configured not to obtain the voltage utilization rate of 0.3 to 0.4.

Parameters relating to rotation of a motor (2) measured every constant time are acquired and the moving average of each constant interval of the parameters is calculated. The calculated moving averages are input to a training model trained so as to output a temperature of magnets attached to a rotor (7) of the motor (2) when the moving averages of the parameters relating to rotation of the motor (2) are input, and an estimated value of the magnet temperature output from the model is acquired. Next, the acquired estimated value of the magnet temperature is output.