A drive system for a BLDC motor having poles implemented by separate coils that are activated in corresponding phases, which comprises a controller for controlling the level and phase of input voltages supplied to the separate coils; a controlled inverter with outputs, for applying phase-separated input voltages to each of the separate coils at desired timing for each input voltage, determined by the controller; a power source for feeding power to the controlled inverter; an up/down DC-DC converter for converting the feeding power to the input voltages according to a command signal provided by the controller. The controller is adapted to sample the instantaneous angle of the rotor of the BLDC motor; sample the input voltage input voltage and the current of each phase to obtain the input power P; and for each input voltage, calculate the phase difference value that corresponds to the input power and feeds the phase difference value to the up/down DC-DC converter, thereby causing the up/down DC-DC converter to apply each input voltage to its corresponding coil at a specific timing for obtaining an optimal match between each input voltage and the current that is being built up in the corresponding coil.

The torque of a permanent magnet motor is increased. There is provided a permanent magnet type motor with concentrated windings, in which each stator pole has a circumferential pitch of 185° or more in an electric angle. In this motor, the circumferential distribution of the magnetic flux density in an air gap surface of the rotor poles PR of the permanent magnet type has an approximately trapezoidal shape. Moreover, the induced voltages of the concentrated windings of the stator have an approximately trapezoidal waveform. An approximately trapezoidal-shaped waveform current is energized in the concentrated winding of each phase. Even if the magnetic flux density is close to the maximum flux density of the soft magnetic member of the stator, large slot cross-sectional areas of the stator can be secured, thus outputting a large torque.

Systems and methods for sensorless trapezoidal control of brushless DC motors provide effective high-torque startup and low speed operation without the use of Hall effect sensors or encoders during motor operation. The systems and methods also provide the ability to boost signal-to-noise ratio for motor startup and low speed operation via an augmenting supply voltage. Sampling architectures and current-dependent inductance modeling architectures for the control systems are also described.

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 controller comprises a switch circuit and a control unit. The switch circuit is coupled to a motor for driving the motor. The control unit is configured to generate a control signal to control the switch circuit. The motor controller is configured to generate a current signal and a voltage signal. When a current phase of the current signal is at a predetermined crossing phase, the motor controller calculates a difference value between the current phase of the current signal and a voltage phase of the voltage signal, where the motor controller is configured to control the difference value. The motor controller may stabilize the motor and avoid noise by modulating the difference value. The motor controller may modulate the difference value, such that the difference value is equal to a predetermined phase difference.

A motor drive signal generator configured to combine at least a part of a first input waveform with at least a part of a second input waveform to create a compound waveform, wherein the first waveform is a sine wave and the second input waveform is a square wave.

A motor device 100 includes an SPM motor 1 that includes a stator 2 including an iron core 21 and a plurality of windings 23 wound on the iron core 21, and a rotor 3 which is rotatable with respect to a rotation axis and in which a plurality of permanent magnets 33 are mounted along a circumferential direction to form a plurality of magnetic poles in the circumferential direction; and a power supply unit 5 that supplies a current to the plurality of windings 23 of the SPM motor 1. Each of the plurality of magnetic poles is oriented such that directions of axes of easy magnetization are concentrated toward a stator side, and the current supplied from the power supply unit is a trapezoidal wave.

A control device capable of suppressing electromagnetic force applied to a motor has a harmonic current calculation section and an operation section. The harmonic current calculation section calculates amplitude and phase of each of harmonic currents to be superimposed over a fundamental current which flows in phase windings of a stator of the motor based on conditions relating to load change of the motor. The operation section generates and transmits instruction signals to an inverter so that the calculated superimposed harmonic currents flow in the phase windings of the stator.

A motor control device generates three-phase drive currents having a phase difference by combining on-off actions of switching elements and supplies the three-phase drive currents to three-phase coils of a brushless motor. The motor control device includes a drive circuit including a bridge circuit that uses multiple switching elements and a control circuit that sets a control pulse, which causes each of the switching elements to perform on-off actions. The control circuit includes a control pulse generating unit that generates a control pulse. The control circuit further includes a set value retaining unit that retains a set value of an on-time length of the control pulse, which is referred to when the control pulse is generated in the control pulse generating unit. The control circuit further includes a set value changing unit that changes the set value retained in the set value retaining unit.

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.