A power tool is provided including: an electric brushless direct current (BLDC) motor having a rotor and a stator. The stator includes at least six teeth including a first set of teeth on which a first set of stator windings are wound and a second set of teeth on which a second set of stator windings are wound. The first and second sets of stator windings are alternatingly arranged relative to the stator. The first set of stator windings is connected in a wye configuration and the second set of stator windings is connected in delta configuration.

The present disclosure relates to an apparatus and method for controlling switching of a wiring mode of a motor capable of being operated in a plurality of wiring modes, a motor control apparatus includes a motor including a rotor that rotates according to a motor torque by a pulse width modulation (PWM) control, a switching unit provided at the motor and switching a wiring method inside the motor so that the motor is driven according to another wiring mode, and a controller generating a speed command frequency for controlling a rotation speed of the rotor, and controlling the switching unit so that the wiring mode of the motor is switched according to a result of comparing the speed command frequency with a switching boundary frequency according to the wiring mode of the motor, wherein when the PWM control is stopped in response to the switching of the wiring mode, the controller estimates a rotation state of the rotor that rotates inertially, and when the PWM control is restarted, the controller sets the estimated rotation state of the rotor as an initial value of the rotor, and controls a rotation speed of the motor of which the wiring mode is switched based on the set initial value of the rotor.

A power tool is provided including: an electric brushless direct current (BLDC) motor having rotor and a stator defining phases; a power unit including a first switch circuit connected electrically between a first power supply and the motor, and a second switch circuit connected electrically between a second power supply and the motor; and a controller configured to control a switching operation of the first switch circuit and the second switch circuit to regulate a supply of power from at least one of the first power supply and/or the second power supply to the motor.

An electric motor drive unit includes a winding switching unit that switches a configuration of windings of an electric motor, a winding switching instruction unit that generates an instruction signal for the winding switching unit, and a winding configuration retention unit to which the instruction signal generated by the winding switching instruction unit is input, and if the input instruction signal has a first value, outputs a signal corresponding to the input instruction signal to the winding switching unit, and if the input instruction signal has a second value different from the first value, continues outputting a signal that has been output to the winding switching unit before the reception of the second value, the first value indicating an instruction on the configuration of the windings.

To provide a rotary electric machine apparatus which can make the rotary electric machine output torque, and can change characteristics of a rotary electric machine according to change of the DC power voltage, even if failure occurs in one DC power source. A rotary electric machine apparatus (1) is provided with a power source switching mechanism (23) that switches between the DC power of low voltage and the DC power of high voltage; a winding connection switching mechanism (24) that switches interconnection of the plural-phase windings between a first winding connection state, and a second winding connection state in which an induced voltage constant of windings becomes lower than the first winding connection state; a inverter (12) provided with the switching devices; and a controller (25) that switches the power source switching mechanism (23), switches the winding connection switching mechanism (24), and controls on/off of the switching devices.

A driving device drives a motor having coils. The driving device includes a converter to generate a bus voltage, an inverter to convert the bus voltage to an AC voltage and supply the AC voltage to the coils, and a connection switching unit to switch a connection state of the coils. The bus voltage generated by the converter is switched in accordance with the connection state of the coils.

This present disclosure provides a compressor and a refrigeration device having the compressor. The refrigeration device has a coupling assembly and a frequency converter connected to one end of the coupling assembly. The compressor has a first shell and a permanent magnet motor. The permanent magnet motor is set in the first shell and connected to the other end of the coupling assembly. By designing the relevant parameters of the motor of the compressor, the efficiency of the motor and the compressor can be improved.

An electric motor drive device includes: a wire connection switching unit; an inverter; a control device controlling the wire connection switching unit and the inverter; and an overcurrent protection circuit preventing current exceeding a predetermined value from continuously flowing through the electric motor. The overcurrent protection circuit includes: determination circuits each correlated one-to-one with any one of possible wire connection states of a stator winding and determining whether current flowing through the inverter is abnormal; a combining circuit combining determination results; and an invalidation circuit invalidating a determination process by one or more of the determination circuits, and causing the combining circuit to output a determination result by the determination circuit correlated with a selected wire connection state of the stator winding. When the determination result output from the combining circuit indicates an abnormal value of the current flowing through the inverter, the control device stops the inverter.

A motor drive device capable of switching the connection configuration of the stator windings of a motor includes three relays each including a first contact, a second contact, and a contact plate, where the contact plate has one terminal coupled to a stator winding of one phase among the stator windings and the contact plate has another terminal to be connected to the first contact or to the second contact; and a control unit to control the three relays to cause all the three relays to have a same connection state in a case in which not all the three relays have a same connection state with respect to connections between the another terminal of the contact plate and the first contact and the second contact.

An air conditioner includes a compressor to compress a refrigerant used in a refrigeration cycle, a converter to generate DC voltage, an inverter to generate three-phase AC voltage from the DC voltage, a motor to generate driving force to drive the compressor by using a plurality of coils to which the three-phase AC voltage is applied, a connection switching unit to switch connection states of the plurality of coils, and an outdoor control device to control the connection switching unit. The outdoor control device restricts the switching of the connection states when a switching count of the connection states exceeds a count threshold value.