A BLDC motor comprising a permanent magnet motor rotor defining a motor axis, a motor housing and a plurality of phase winding circuits mounted on the motor housing to form a stator, wherein each phase winding circuit comprises a phase winding and a driving bridge which is to operate to drive a phase current to flow through the phase winding, and the driving bridge comprises a switching circuit to provide a switched power supply to energize the phase winding; and wherein the phase windings are disposed at different angular positions with respect to the motor axis or the motor housing.

An over temperature protection circuit includes a temperature sensor unit, a detection unit, and a filter unit. The temperature sensor unit detects a temperature and outputs a temperature detection signal. The detection unit has a first threshold for determining whether a temperature state is a normal state, and a second threshold for determining whether the temperature state is an over temperature state; and operates with respect to an internal ground. The detection unit determines the normal state or the over temperature state, based on the level of the temperature detection signal with respect to the first threshold and the second threshold; and outputs a state signal. The filter unit filters out a change of the state signal, produced in accordance with a change of the internal ground.

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.

An AC to DC conversion device has first and second AC input terminals arranged to be coupled respectively to first and second terminals of a phase of an AC current generator, an H-bridge rectification device comprising two pairs of diodes, each pair being coupled to a respective one of the AC terminals to produce a DC output comprising a rectified back EMF waveform, and a waveform generator. The waveform generator comprises an output coupled to the DC output of the H-bridge rectification device, and is configured to input a unidirectional waveform to the DC output having the same magnitude and fundamental frequency as the rectified back EMF, phase shifted by a predetermined angle relative to the rectified back EMF waveform.

A motor control device for controlling a brushless motor including a rotor and a three-phase armature coil includes: a position detection unit which detects the rotational position of the rotor; a control unit which outputs, in a first control mode or a second control mode, a first drive signal or a second drive signal to an inverter at a current-supply timing based on the rotational position of the rotor; and the inverter which outputs a first current-supply signal or a second current-supply signal to the three-phase armature coil when the first drive signal or the second drive signal is input. For any two of the three phases, a duty value when the duty of the applied voltages is the same is larger in the second control mode than in the first control mode.

The present invention discloses a modulation method for inverter AC waveform. The detailed steps of the modulation method comprise: generating an AC waveform which includes at least three time periods, wherein a middle time period corresponds to a peak segment of the AC waveform, and the remaining time periods are averaged corresponding to the rise and decline segments of the AC waveform; and during the at least three time periods, a duty ratio modulated driving signal is generated according to different duty ratios, so as to modulate the AC waveform and generate a stepping AC waveform converted from the AC waveform. The stepping AC waveform generated by the modulation method of the present invention will have a longer dwell time at zero potential, so as to turn on the AC electric tool more efficiently.

A motor driver having a high success rate starting mechanism is provided. A multi-segment slope pattern circuit connects a plurality of values of waveforms of a starting waveform signal to form a curve. The multi-segment slope pattern circuit determines a plurality of slopes respectively of a plurality of curve segments included in the curve according to a plurality of parameters related to a motor. The multi-segment slope pattern circuit outputs a multi-segment slope pattern signal according to the plurality of slopes of the plurality of curve segments. A startup signal generating circuit outputs a first startup waveform signal according to the multi-segment slope pattern signal. A motor controller circuit controls a motor driving circuit to start up the motor according to the first startup waveform signal.

A motor controller includes a plurality of inverters that supply power to a corresponding motor of a plurality of motors through pulse width modulation control, a direct current power supply that supplies power to the plurality of inverters, and a capacitor connected parallel to the direct current power supply. Each of the plurality of inverters is categorized into one of a plurality of groups based on a switching frequency. All inverters in each of the groups have corresponding carrier signals being triangular wave signals determined based on a reference frequency assigned to the group. At least one of the triangular wave signals has at least one of a frequency or a phase different from a frequency or a phase of another triangular wave signal of the triangular wave signals.

In a hybrid vehicle, noise occurrence caused in a rectangular wave control of a motor is restricted when a motor running mode is selected with a converter boosting limit applied. A motor controller for a hybrid vehicle mounted with an internal combustion engine and a motor as power sources is provided. The motor controller includes a converter capable of boosting a voltage supplied from a power supply device; an inverter which converts an output voltage of the converter to an AC voltage and applies the AC voltage to the motor; and a control unit which controls the inverter to drive the motor by switching between two or more control modes. When a running mode to drive the vehicle by a motor power alone is selected with a boost limit applied to the output voltage of the converter and when the motor is driven in a rectangular wave control mode or an overmodulation PWM control mode, the control unit raises the output voltage of the converter higher than a boost limit value and controls the inverter such that the control mode is switched to drive the motor in a sinusoidal PWM control mode.

An over temperature protection circuit includes a temperature sensor unit, a detection unit, and a filter unit. The temperature sensor unit detects a temperature and outputs a temperature detection signal. The detection unit has a first threshold for determining whether a temperature state is a normal state, and a second threshold for determining whether the temperature state is an over temperature state; and operates with respect to an internal ground. The detection unit determines the normal state or the over temperature state, based on the level of the temperature detection signal with respect to the first threshold and the second threshold; and outputs a state signal. The filter unit filters out a change of the state signal, produced in accordance with a change of the internal ground.