A method for controlling an electric drive system and the electric drive system. The method includes: measuring an external variable; estimating a control variable for a current sampling step with a mathematical model; predicting a control variable for a future sampling step for each of a plurality of candidate voltage vectors selected for the future sampling step; and calculating a cost function, and identifying a primary voltage vector giving a minimum, where the cost function is defined as a deviation between the predicted stator flux and the reference stator flux. The method further includes: predefining a lookup table giving a correlation between a nonzero voltage vector and a voltage vector group including four candidate voltage vectors, where the plurality of candidate voltage vectors is selected referring the lookup table. The electric drive system includes motor, power converter, and controller, and configured to perform the method.

In the work device that has a self-holding circuit (61) maintaining power supply from a power supply circuit (12) by output from a microcomputer (40) and has a structure in which stopping output to the self-holding circuit (61) causes interruption of power supply from the power supply circuit (12) to the microcomputer (40), the firmware of the microcomputer (40) is made to be rewritable and a power holding unit (condenser (C1)) for temporarily continuing power supply to the microcomputer (40) is provided, thereby realizing a so-called off-delay timer function for restarting the microcomputer (40). This configuration enables maintenance of power to the microcomputer (40) after update of the firmware even in a work device that cannot be restarted once power has been turned off unless trigger operation is performed, thereby enabling automatic restart of the microcomputer 40 after resetting is enabled.

A motor control system includes a motor and a motor control circuitry. The motor includes a rotation axis and a bearing rotatably supporting the rotation axis. The motor control circuitry is configured to control the motor. The motor control circuitry includes a driving time adding circuit configured to add up a driving time of the motor to obtain an accumulated driving time of the motor, a remaining lifetime calculation circuit configured to calculate a remaining lifetime of the bearing based on a lifetime of the bearing and the accumulated driving time, and a warning outputting circuit configured to output warning information when the remaining lifetime is equal to or less than a threshold.

A motor assembly includes a motor, a control circuit to generate a control signal, a motor driving circuit to cause a current to flow in the motor based on the control signal, a storage to store a first identifier uniquely identifying itself and a second identifier uniquely identifying another motor assembly within the communications network, and a communication circuit. The communication circuit transmits a data frame, in which the first identifier indicates a transmitting end, the second identifier indicates a receiving end, and a request are stored. The communication circuit receives from the other motor assembly a data frame including the second identifier indicating a transmitting end, the first identifier indicating a receiving end, and a request. In response the communication circuit transmits a data frame including the second identifier indicating a receiving end added thereto and the first identifier indicating a transmitting end added thereto.

A percussive massage device with a force meter that includes a housing, an electrical source, a motor positioned in the housing, a switch for activating the motor, and a controller configured to obtain a voltage of the motor, generate a lookup table correlating voltage to force applied by the percussive massage device, and display a force magnitude corresponding to the obtained voltage using the lookup table.

An adaptive torque disturbance cancellation method and motor control system for rotating a load are described. The system has: (i) a speed controller for receiving a first input signal indicating a desired motor speed and, in response, for outputting a motor control signal; (ii) current sensing circuitry for sensing current through a motor that rotates in response to the speed controller; (iii) circuitry for storing, into a storage device, history data representative of the current through a motor when the motor operates to rotate the load; and (iv) circuitry for modifying the motor control signal in response to the history data.

A voltage saturation prevention algorithm used as at least part of a method of controlling an electric vehicle, wherein the electric vehicle comprises an electric motor, a controller, and an inverter. The controller receives a control signal with an instruction to operate the electric motor, then sends a switching signal corresponding to the control signal to the inverter, wherein the inverter provides a plurality of output signals for operation of the electric motor. The method includes determining the expected amplitude of the plurality of output signals based on the instruction to operate the electric motor, calculating the amount of modification of the plurality of output signals required to prevent the expected amplitude from reaching a saturation value, and modifying, based on the calculation, the instruction to operate the electric motor to prevent the expected amplitude from reaching the saturation value. The method is implemented in software, without any additional hardware.

An electric motor capacity selection device includes: a multi-axis system model holding unit that holds a plurality of types of multi-axis system models each representing a configuration of a multi-axis system constructed by combination of a plurality of machine elements and a plurality of electric motors; a capacity selection unit that selects, based on a selected multi-axis system model that is one multi-axis system model selected from among the plurality of types of multi-axis system models held by the multi-axis system model holding unit, capacities of the electric motors constituting the multi-axis system model represented by the selected multi-axis system model; and a selection result notification unit that makes notification of a selection result by the capacity selection unit.

A speed control system of a universal motor is electrically connected with a universal motor and includes a speed detecting unit and a controller. The controller is provided with a slow start unit, a speed control unit and a stopping-protecting unit. The slow start unit enables the rotating speed of the universal motor to increase smoothly, and the speed control unit controls and compensates the rotating speed of the universal motor in a way of closed loop, able to achieve effect of stepless speed adjustment and, when used at low speed, having cutting ability similar to that when operated at high speed. The stopping-protecting unit is able to automatically cut off power and carry out protection when machine table is stopped.

The identification method according to an embodiment is used for an identification device for identifying the type of a brushless DC motor. A brushless DC motor includes an output terminal for outputting a signal. The output terminal is able to output a signal obtained by superimposing signal types. The signal resulting from the superimposition is different depending on the types of brushless DC motors. In the identification method, power is supplied to a brushless DC motor, and the signal resulting from the superimposition that is output from the output terminal of the brushless DC motor is input to an identification device. The signal resulting from the superimposition is separated into signal types, and the separated signals are used to identify the type of the brushless DC motor.