A system includes a generator coupled to an engine and configured to generate electricity from rotational movement of a shaft of the engine, a motor configured to be driven by the generator through one or more power conversion components, the motor configured to drive a load, a sensor configured to measure generator output, and a controller configured to detect engine imbalance based on a frequency content of a signal output from the sensor in response to a contribution to the frequency content from the one or more power conversion components and/or the load of the motor being less than a threshold value.

In one aspect, a system for determining an initial angular position of a rotor of a synchronous machine includes a motor driver module configured to provide a motor driver voltage signal to the synchronous machine, the motor driver voltage signal being sufficient to induce an electrical current in the synchronous machine; and a rotor position determination module configured to receive an indication of the current generated in the machine and to determine the initial position of the rotor based on the indication of the current generated in the machine. The motor driver voltage signal includes at least a first portion, a second portion, and a third portion, the first portion has a first non-zero voltage during a first temporal duration, the second portion has a second non-zero voltage during a second temporal duration, and the third portion has a substantially zero voltage during a third temporal duration, the first portion has a first polarity and the second portion has a second polarity that is opposite to the first polarity, and the first temporal duration and the second temporal duration are different.

A power conversion system includes an inverter and a controller configured to: responsive to startup of the system, measure a motor speed of the IPM motor; responsive to the motor speed being less than a threshold, generate the inverter switching control signals to perform high frequency injection (HFI); during the HFI, determine a measured angle of the IPM motor; during the HFI, generate the inverter switching control signals to provide an injected current to the IPM motor; detect acceleration or deceleration of the IPM motor responsive to the injected current; selectively determine an electrical angle as half the measured angle or as 180 degrees plus half the measured angle based on the detected acceleration or deceleration of the IPM motor; and responsive to determining the electrical angle, generate the inverter switching control signals to drive the IPM motor to a reference frequency in a normal operating mode of the inverter.

The present invention concerns a method and a device for determining a position of a rotor of a three-phase motor using a FOC system. The invention: —determines, by a proportional-integral controller, a first control voltage vector at a first instant, —transforms the first control voltage vector using an inverse Park transform, —sums the transformed first control voltage vector to a regular polygonal voltage pattern applied during a given duration, —performs a PWM from the sum of the transformed first control voltage vector and the regular polygonal voltage pattern, —controls the motor with the pulse-width modulation, —measures the current at each phase of the motor, —estimates the position of the rotor from the measured currents and from the regular polygonal voltage pattern, —determines, at a second instant, a second control voltage vector from the measured currents and from the estimated position.

A controller of a power tool outputs a driving signal to a motor driving circuit and acquires a position of a rotor of a brushless motor. While acquiring the position of the rotor of the brushless motor, a phase voltage or a line voltage of a winding of the brushless motor is detected through the voltage detection circuit. Whether an upper bridge arm switching element, a lower bridge arm switching element, and/or the brushless motor is short-circuited is determined according to the phase voltage or the line voltage of the winding of the brushless motor.

A method for the diagnosis of the offset of the resolver of an electric motor, comprising acquiring a predetermined offset of a resolver associated with the electric motor; in a first transient, supplying an excitation current to the phases of the electric motor. As a consequence of the excitation current, a current established on the axis d of minimum reluctance and a current established on an axis q in phase quadrature with respect to the axis of minimum reluctance are determined. The correctness of the offset of the resolver is diagnosed if the current established on the axis d in the first transient is higher than the current established on the axis d in the second or third transient, and if the current established on the axis q in the first transient is lower than the current established on the axis q in the second or third transient.

The present invention realizes a motor control apparatus and the like capable of obtaining an appropriate frequency characteristic. The motor control apparatus of the present invention includes a command value generating portion (10), a torque saturation detecting portion (61) for determining whether a driving value based on a command value exceeds a driving value capable of being output from the apparatus, a current saturation detecting portion (71), a voltage saturation detecting portion (72), and a command value correcting portion (20) for correcting the command value when the driving value is determined as being exceeded.

A power tool is provided including a housing, a brushless motor disposed within the housing, a power switch circuit that supplies power from a power source to the brushless motor, and a controller configured to receive at least one signal associated with a phase current of the motor, detect an angular position of the rotor based on the phase current of the motor, and apply a drive signal to the power switch circuit to control a commutation of the motor based on the detected angular position of the rotor. If the supply of power to the motor is turned OFF to cause the motor to slow down and is turned back ON while the rotor speed exceeds a speed threshold, the controller electronically brakes the motor for a time interval to measure the phase current of the motor and detects the angular position of the rotor based on the measured phase current.

Disclosed is a motor control apparatus, a motor control system, and a motor control method that estimate a stator resistance and a rotor position for sensorless control of a motor.

Disclosed is a motor control apparatus and a motor control method to estimate a stator resistance of a motor for sensorless control of the motor.