A fluid sprayer includes a housing, a pump, a nozzle, a high voltage direct current (HVDC) brushed electric motor that drives the pump, and a motor controller electrically connected to the motor. The motor controller drives the motor with a high speed pulse width modulated (PWM) drive signal that switches current through the motor on and off. The motor controller varies the PWM signal as a function of a spray setting input and sensed current through the motor.

A power tool includes a multi-phase BLDC motor, a plurality of switches, an input unit, and a controller. For each phase, the controller operates to vary power output to the motor between a first power and a second power by varying a duty cycle of a PWM signal from 0% to 100% while keeping a conduction band (CB) of corresponding motor switches and/or an advance angle (AA) at a predetermined value when the input unit moves between a first position and a predetermined position between the first and a second position. For each phase, the controller operates to increase the power output by the motor to greater than the second power by increasing the CB/AA to greater than the predetermined value while keeping the duty cycle of the PWM signal at 100% when the input unit moves between the predetermined position and the second position.

An electrical system including a three phase AC input supply and three or more H-bridge converter cells. Each H-bridge converter cell has: an active front end rectifier for receiving the three phase AC input supply and transforming it into a DC supply, thereby providing a rectifier current i.sub.i; a capacitor suitable to receive a capacitor current i.sub.C, the capacitor smoothing the DC supply; and an inverter suitable to receive an inverter current i.sub.o, wherein i.sub.o=i.sub.i−i.sub.C, said inverter transforming the received inverter current i.sub.o into a single phase AC supply. The system also including a control subsystem, which provides a signal to each active front end rectifier to vary its respective rectifier current i.sub.i such that the difference between the rectifier current i.sub.i, provided by the active front end rectifier, and the inverter current i.sub.o, received by the inverter, is substantially zero.

A long-distance speed control system for a brushless DC motor of a fan is provided. The long-distance speed control system includes a switch connected with a mains power supply, a switch circuit, a voltage detection module, a power cord, a processing unit, and a drive unit, which can control the multi-stage rotational speed of the motor. In the field of brushless DC motors for fans, there is no need to use analog-to-digital conversion chips between the mains power supply and the processor, having the advantages of low cost, environmental protection, and reduction of waste of earth resources. Besides, the switch, the switch circuit and the power cord can withstand the mains power supply, having the advantages of less signal attenuation and long-distance transmission.

A motor control system, in some embodiments, comprises: a voltage divider circuit having an output node, a voltage on said output node representing a desired motor rotation direction; control logic configured to receive an indication of said voltage; and a motor controller coupled to the control logic, wherein, if said indication of the voltage on the output node falls outside of a predetermined range, the control logic is configured to issue a motor stop signal to the motor controller indicating that at least one resistor of the voltage divider circuit is defective or is missing from the voltage divider circuit.

A motor control system, in some embodiments, comprises: a voltage divider circuit having an output node, a voltage on said output node representing a desired motor rotation direction; control logic configured to receive an indication of said voltage; and a motor controller coupled to the control logic, wherein, if said indication of the voltage on the output node falls outside of a predetermined range, the control logic is configured to issue a motor stop signal to the motor controller indicating that at least one resistor of the voltage divider circuit is defective or is missing from the voltage divider circuit.

A ripple current sensing type motor controlling apparatus includes: an H bridge circuit switched depending on at least one control; a first resistor of which one end is connected to one end of the motor through the H bridge circuit and the other end is connected to a ground; a second resistor of which one end is connected to the other end of the motor through the H bridge circuit and the other end is connected to one end of the first resistor and is connected to one end of the motor through the H bridge circuit; and a controller calculating a RPM of the motor using a voltage across the first resistor in the case in which the driving power is applied to the motor and calculating the RPM of the motor using a voltage across the second resistor in the case in which the driving power is blocked.

A direct current traction motor control system includes plural motors of with each of the motors configured to be coupled with a different axle of a vehicle and to rotate the axle to propel the vehicle. The motors are coupled with a DC bus and configured to receive DC via the DC bus to power the motors. The system also includes plural switch assemblies with each of the switch assemblies having an H-bridge circuit coupled with a different motor of the motors to control rotation of the motor. The system includes a controller configured to communicate control signals to the switch assemblies to individually control the H-bridge circuits to control one or more of torques output by the motors or rotation directions of the motors.

A drive control device includes: a driver including a circuit and configured to drive a motor; and a controller configured to control the driver. The controller is configured to: in a period other than a stop period during driving of the motor, control the driver by a PWM control of a synchronous rectification type, the stop period lasting for a specified time or longer during the driving of the motor; and in the stop period during the driving of the motor, suspend the PWM control of the synchronous rectification type and control the driver such that the motor is set to a short-circuit brake state or a disconnected state.

A motor system with an input for coupling to a motor control signal that, when presented in a predetermined state, indicates a motor receiving power should be disabled from rotating. The system also includes controller circuitry for providing a disabling signal to motor rotation, independent of processor software control signaling and the power, in response to the control signal.