A linear resonant device and a braking method for the same. The linear resonant device comprises a linear resonant motor and a drive chip. The drive chip pre-stores a drive waveform and at least one first braking waveform therein. The method comprises: determining, in response to a braking instruction, whether vibration of the linear resonant motor meets a first condition while being driven by the drive waveform; and if so, controlling the drive chip to drive, by using the first braking waveform, the linear resonant motor and to conduct a first braking process for the linear resonant motor, wherein the first braking waveform comprises at least two pulse waveforms, and an amplitude value of each of the at least two pulse waveforms gradually decreases along a propagation direction of the first braking waveform.

A motor driver having a startup adjusting mechanism is provided. A steady-state detector circuit detects data for driving a motor to stably rotate to output a steady-state detected signal. A startup waveform pattern circuit selects one of a plurality of startup waveform patterns to output a startup waveform pattern signal according to the steady-state detected signal. A startup waveform generator circuit outputs a startup waveform signal according to the startup waveform pattern signal. A motor controlling circuit controls a motor driving circuit to start up the motor according to the startup waveform signal.

The invention relates to the actuation of an electric machine with a change between time-synchronous PWM clocking and angle-synchronous block clocking It is proposed to provide an angle-synchronous clocking with adjustable voltage indicator length for the transition. In this way, jumps in the operating behavior of the electric machine can be minimized or optionally prevented completely during a change between time-synchronous clocking and angle-synchronous clocking.

A motor drive device includes a single-phase inverter which is an inverter including a plurality of switching elements. The inverter converts a direct-current voltage output from a direct-current power supply into an alternating-current voltage, by operation of the plurality of switching elements operating, and applies the alternating-current voltage to a motor. The motor drive device includes a control power supply outputting power having a voltage lower than the direct-current voltage, by using the direct-current voltage. The motor drive device includes a drive signal generation unit driven by the power. The drive signal generation unit generates drive signals driving the plurality of switching elements, and outputs the generated drive signals to the plurality of switching elements. The motor drive device includes a power supply switch operating so as to allow supply of the power from the control power supply to the drive signal generation unit when a rotation speed of the motor is higher than a threshold. The power supply switch operates so as to stop the supply of the power from the control power supply to the drive signal generation unit when the rotation speed is lower than the threshold.

A control apparatus controls an inverter which outputs electric power to an electric motor. The control apparatus determines which one of a one-pulse control and a pulse-width modulation control is employed as a control method of the inverter in accordance with a predetermined condition based on an electric motor drive torque of the electric motor, a rotation number of the electric motor, and a DC voltage of the electric motor.

A method is provided for operating a frequency converter, which is designed to drive a three-phase motor, wherein the frequency converter has three half-bridges each having at least two switches. The method includes the following steps: generating three phase voltages for the three-phase motor by a pulse width modulation, wherein, for the pulse width modulation, various switching patterns of the switches are activated, wherein specific star point voltages ensue for various groups of switching patterns; and in at least one operating state of the frequency converter, within a respective period of the pulse width modulation, activating only those switching patterns in which an identical star point voltage ensues.

A feedback control switching unit of an inverter control unit selects, based on a magnitude relationship between a predetermined switching determination amount and at least one switching threshold, at least one of feedback control units to thereby execute switching among feedback control modes, such as a current feedback control mode and a torque feedback control mode, of the respective feedback control units for driving of the AC motor. A switching command generating unit generates a switching command for an inverter based on a manipulated variable calculated by the selected feedback control unit. When a torque response request determining unit determines that a required torque responsiveness is high, the feedback control switching unit reduces the number of executions of switching among the feedback control modes.

According to the present invention, in position sensorless control for switching between a 120-degree energization scheme for a low-speed region and a 180-degree energization scheme for a mid-to-high-speed region, stable and highly accurate speed control characteristics are provided by suppressing speed deviation r in the low-speed region, and by preventing current jump-up caused by a discontinuous rotational speed occurring during switching to the mid-to-high-speed region. In the case of driving in the 120-degree energization scheme, a voltage command value is corrected such that an estimated speed value or a detected speed value follows a speed command.

A method for driving an electric motor includes providing two controllers for driving the electric motor. The two controllers use different control methods to drive the electric motor. The method further includes selecting a first controller of the controllers as a primary controller to drive the electric motor and a second controller of the controllers as a secondary controller, monitoring a control of the electric motor, and switching the control of the electric motor from the primary controller to the secondary controller if an error condition is detected in the control of the electric motor.

In a motor drive device 120, a phase compensation amount calculation unit 110 calculates a phase compensation amount for compensating a voltage phase v* when a control mode is switched in a control selection unit 90. The control selection unit 90 outputs the three-phase voltage command Vuvw* according to any one of the plurality of control modes based on the modulation factor Kh*, the voltage phase v*, and the phase compensation amount . A PWM control unit 100 outputs gate signals Gun, Gup, Gvn, Gvp, Gwn, and Gwv based on the three-phase voltage command Vuvw* and a rotor position d. The inverter 20 has a plurality of switching elements, and controls the plurality of switching elements based on gate signals Gun, Gup, Gvn, Gyp, Gwn, and Gwv to drive the AC motor 10.