A PCB motor controller comprises relays mounted on a PCB and interconnected to power traces in or on the PCB to receive incoming three-phase power and to output three-phase power to a motor. Control power traces in or on the PCB connect the relays to control circuitry, also mounted on the PCB. A power supply is mounted on the PCB and connected to the control circuitry to provide power for its operation and for switching of the relays. The relays are switched in accordance with a point-on-wave (POW) switching scheme, allowing for the use or relays and the PCB, which may not otherwise be suitable for motor control applications.

A PCB motor controller comprises relays mounted on a PCB and interconnected to power traces in or on the PCB to receive incoming three-phase power and to output three-phase power to a motor. Control power traces in or on the PCB connect the relays to control circuitry, also mounted on the PCB. A power supply is mounted on the PCB and connected to the control circuitry to provide power for its operation and for switching of the relays. The relays are switched in accordance with a point-on-wave (POW) switching scheme, allowing for the use or relays and the PCB, which may not otherwise be suitable for motor control applications.

A system and method for starting electric motors. A controller attempts to start a motor without applying a brake to the rotor. If the motor fails to start, the controller applies a strength of braking and then again attempts to start the motor. If the motor still fails to start, the controller iteratively increases the strength of braking and attempts to start the motor until a maximum strength of braking and/or a maximum number of attempts to start the motor is reached. Alternatively, a sensing system first determines whether the rotor is rotating. If the rotor is rotating, the sensing system determines the speed of rotation, the controller determines a strength of braking that will halt the rotation based on the speed of rotation, applies that strength of braking to halt the rotation of the rotor, and then attempts to start the motor.

A system and method for starting electric motors. A controller attempts to start a motor without applying a brake to the rotor. If the motor fails to start, the controller applies a strength of braking and then again attempts to start the motor. If the motor still fails to start, the controller iteratively increases the strength of braking and attempts to start the motor until a maximum strength of braking and/or a maximum number of attempts to start the motor is reached. Alternatively, a sensing system first determines whether the rotor is rotating. If the rotor is rotating, the sensing system determines the speed of rotation, the controller determines a strength of braking that will halt the rotation based on the speed of rotation, applies that strength of braking to halt the rotation of the rotor, and then attempts to start the motor.

One embodiment describes a method that includes determining, using a control circuitry, temperature of a switching device before a make operation by applying a measurement current to an operating coil of the switching device, wherein the measurement current is insufficient to make the switching device; and determining voltage at the operating coil when the measurement current is applied, in which the voltage at the operating coil is directly related to the temperature. The method further includes determining, using the control circuitry, when to apply a pull-in current to the operating coil to close the switching device based at least in part on the voltage at the operating coil, such that the switching device makes at a desired time.

One embodiment describes a tangible, non-transitory, computer-readable medium storing instructions executable by a processor of an operating coil driver circuitry. The instructions include instructions to instruct a switch to supply a specific current to an operating coil of a switching device using a pulse-width modulated signal; determine duty cycle of the pulse-width modulated signal; and determine wellness of the switching device based at least in part on the duty cycle of the pulse-width module signal.

One embodiment describes a tangible, non-transitory, computer-readable medium storing instructions executable by a processor of an operating coil driver circuitry. The instructions include instructions to instruct a switch to supply a specific current to an operating coil of a switching device using a pulse-width modulated signal; determine duty cycle of the pulse-width modulated signal; and determine wellness of the switching device based at least in part on the duty cycle of the pulse-width module signal.

Provided is a wire connecting structure of coils of a three-phase motor, a wire connecting method and three-phase motor, which is capable of reducing a size of a short circuit terminal for a neutral point. The wire connecting structure is a wire connecting structure of coils which are wound to each salient-pole in a three-phase motor having respective salient-pole of a U phase, a V phase and a W phase, the coils of the salient-poles belonging to any two phases among the U phase, the V phase and the W phase are formed by a single continuous first conducting wire, and the coil of the salient-pole belonging to the rest one phase is formed by a single continuous second conducting wire.

An air conditioner and a startup control method and system for an outdoor fan of the air conditioner. While in a process of charging a bootstrap capacitor in an actuator of a motor of the outdoor fan, an initial rotation state of the motor is detected in real time, and, when charging of the bootstrap capacitor is completed, startup of the motor is correspondingly controlled on the basis of the detected initial rotation state. This allows real time initial startup work state to be acquired when charging of the bootstrap capacitor is completed, thus allowing the motor to be started smoothly, increasing the success rate in starting the motor, and solving the problem of low success rate in starting the motor of an outdoor fan.

A system (10) applied in switch tube for suppressing conducted EMI and a domestic appliance are provided, and the system (10) includes a conduction EMI suppression circuit, an inductive load (1, 71, 81) and at least one switch tube (2, 72, 82). The conducted EMI suppression circuit includes one inductor (3, 73, 83, 123) and an RC circuit (4, 74, 84, 124). The inductor (3, 73, 83, 123) and each switch tube (2, 72, 82) are connected in series. The inductive load (1, 71, 82) and each switch tube (2, 72, 82) are connected. The inductor (3, 73, 83, 123) are connected in series with each switch tube (2, 72, 82), and further connected in parallel with the RC circuit (4. 74, 84, 124). The conduction EMI suppression circuit is configured to suppress conducted EMI generated by each switch tube (2, 72, 82) being turned off.