A method and a parameter estimation system are provided for controlling an electrical machine, (e.g., an induction motor), powered by a drive unit. The method and the parameter estimation system disclosed herein detect a travelling wave generated on a linking element disposed between a first connection point, which is at least one terminal of the electrical machine, and a second connection point, which is at least one terminal of the drive unit. Further, the method and the parameter estimation system disclosed herein obtain at least one of a plurality of wave characteristics associated with the travelling wave, (e.g., an amplitude, a width, a frequency, a travel time of the travelling wave). Further, the method and the parameter estimation system disclosed herein determine one or more control parameters, (e.g., an operational torque and speed), of the electrical machine based on at least one of the wave characteristics.

An apparatus for controlling an inverter for driving a motor includes a processor which includes: a current processor for generating a voltage command for causing a current detection value obtained by measuring a current supplied from the inverter to the motor to follow a current command for driving the motor; a voltage modulator for generating a pulse width modulation signal for controlling on and off states of switching elements in the inverter with a predetermined switching frequency based on the voltage command; and a frequency determining processor for setting a frequency change range within which the switching frequency will be randomly changed and randomly determining the switching frequency within the frequency change range when a random pulse width modulation method is applied to control of the inverter.

A controller of an electrically powered vehicle includes an electronic control unit. The electronic control unit performs a switching control by a square wave control in a first switching mode when a rotation speed of the motor is equal to or higher than a first predetermined rotation speed. The electronic control unit performs the switching control by the square wave control in a second switching mode when the rotation speed of the motor is lower than the first predetermined rotation speed. The first predetermined rotation speed is a rotation speed lower than a first resonance region. The first switching mode is a mode of a switching pattern that suppresses LC resonance in the first resonance region. The second switching mode is a mode of a switching pattern that suppresses LC resonance in a second resonance region lower than the first predetermined rotation speed.

The invention relates to an adjustment of a PWM frequency in a power converter in accordance with the input voltage of the power converter. By means of the adjustment of the PWM frequency in the power converter in accordance with the input voltage, a ripple on the input side of the power converter can be varied. In particular, it is possible, in the case of high input voltages, to minimize the ripple by adjusting the PWM frequency and thus to reduce the sum of the input voltage and the ripple.

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.

Provided is a drive control device including: a DC voltage source; an inverter configured to switch a switching element, to thereby apply a drive voltage to a rotary electric machine to cause a drive current to flow through the rotary electric machine; and a control unit configured to: control an output voltage of the DC voltage source; and perform control of causing, based on a torque command value for the rotary electric machine, a drive current to flow through the switching element in a first control mode, in which a drive current having a value equal to or smaller than a first current limit value is caused to flow, and a second control mode, in which a drive current having a value larger than the first current limit value is caused to flow.

A device and a method for automatically detecting an initial position of a rotor of a motor are provided. The device includes an initial position detector, a lookup table module and a controller. The initial position detector detects input voltages of the motor. The controller compares the input voltages with each other to determine the initial position of the rotor of the motor. The controller obtains a waveform pattern from the lookup table module to construct an activating waveform signal to be outputted to one of steps of the motor that corresponds to the initial position of the rotor to control the motor to run.

A device and a method for automatically detecting an initial position of a rotor of a motor are provided. The device includes an initial position detector, a lookup table module and a controller. The initial position detector detects input voltages of the motor. The controller compares the input voltages with each other to determine the initial position of the rotor of the motor. The controller obtains a waveform pattern from the lookup table module to construct an activating waveform signal to be outputted to one of steps of the motor that corresponds to the initial position of the rotor to control the motor to run.

An electrical motor device according to the present invention is provided with a control unit. The control unit is configured to adjust the ratio of transformation by adjusting the ratio between a first time period, in which all upper-arm-side switching elements are on and all lower-arm-side switching element are off, and a second time period, in which all upper-arm-side switching elements are off and all lower-arm-side switching elements are on, and to select one of a plurality of driving modes for each control cycle. The plurality of driving modes include: a dual-driving mode including the first time period and the second time period in one control cycle during electrical motor driving; and an electrical motor driving mode not including the first time period and the second time period in one control cycle during electrical motor driving.

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.