A safety switching system and method for braking an electric motor in a mobile device. A multi-phase shorting system brakes the motor by diverting power from the motor windings. Multiple independent switching units each include a switch control unit controlling multiple normally-closed switches which, in response to a safety controller, close to connect a respective motor winding to electrical ground. An electromechanical brake system mechanically brakes the motor. An independent switching unit includes two normally-open switches which, in response to the safety controller, opens to activate an electromechanical brake. A feedback system communicates to the safety controller a switch failure of any of the switches either as a short circuit fault or an open circuit fault. The feedback system may include an analog and/or a digital feedback system. If a switch failure is detected, the safety controller may activate the multi-phase shorting system and the electromechanical brake system.

A safety switching system and method for braking an electric motor in a mobile device. A multi-phase shorting system brakes the motor by diverting power from the motor windings. Multiple independent switching units each include a switch control unit controlling multiple normally-closed switches which, in response to a safety controller, close to connect a respective motor winding to electrical ground. An electromechanical brake system mechanically brakes the motor. An independent switching unit includes two normally-open switches which, in response to the safety controller, opens to activate an electromechanical brake. A feedback system communicates to the safety controller a switch failure of any of the switches either as a short circuit fault or an open circuit fault. The feedback system may include an analog and/or a digital feedback system. If a switch failure is detected, the safety controller may activate the multi-phase shorting system and the electromechanical brake system.

The invention relates to fluid drive systems used in fluid wells and brake systems for permanent magnet wellhead direct drives. The braking controller connects or disconnects a brake resistor from a back EMF. A variable frequency drive (VFD) drives the motor and communicates with the control circuitry of the brake controller. The control circuitry monitors the brake resistor and depending on the rotational speed and direction of the motor and operating state of the VFD, disconnects or connects the brake resistor. If the direction of the motor is in reverse and above a threshold speed, it connects the brake resistor. If the direction of the motor is in reverse and below the threshold speed, the control circuitry dissipates stored back EMF through the brake controller. The amount of stored back EMF corresponds to the time to empty a pump.

The invention relates to fluid drive systems used in fluid wells and brake systems for permanent magnet wellhead direct drives. The braking controller connects or disconnects a brake resistor from a back EMF. A variable frequency drive (VFD) drives the motor and communicates with the control circuitry of the brake controller. The control circuitry monitors the brake resistor and depending on the rotational speed and direction of the motor and operating state of the VFD, disconnects or connects the brake resistor. If the direction of the motor is in reverse and above a threshold speed, it connects the brake resistor. If the direction of the motor is in reverse and below the threshold speed, the control circuitry dissipates stored back EMF through the brake controller. The amount of stored back EMF corresponds to the time to empty a pump.

Motor control systems and methods for micromobility transit vehicles are provided. A micromobility transit vehicle may include an electric motor configured to drive a rotation of a wheel. The electric motor may include a plurality of windings and a plurality of switching circuits. The switching circuits may be configured to selectively direct current from a power supply through the windings to generate a torque by the electric motor to drive the rotation of the wheel in response to associated control signals. The switching circuits may be configured to passively bypass the windings in response to an interruption of the control signals. Depletion of the power supply may result in the interruption of the control signals.

A drive control device for a motor includes an input terminal, an output terminal, an inverter circuit, a first switch unit, a capacitor, a diode, a rectifier circuit, a photo coupler, a second switch unit, and a voltage detector. The inverter circuit converts a direct current voltage into an alternating current voltage, and outputs the alternating current voltage to the output terminal. The first switch unit shorts the output terminal based on a control signal. The capacitor is connected to the input terminal, and is charged by a direct current voltage. The diode is connected between the input terminal and the capacitor. The diode limits a direction where a charge current for charging the capacitor flows. The rectifier circuit rectifies an induced voltage, which is generated in the motor, and outputs a rectified voltage. The photo coupler converts the rectified voltage into an optical signal, and thereafter, converts the optical signal into a converted signal. The second switch unit outputs the control signal based on the converted signal. The voltage detector detects whether the direct current voltage is input to the input terminal, and determines whether to negate the control signal.

A method for controlling a braking torque of a drive system and for braking a vehicle includes in a first state connecting phase connections of a synchronous machine to one another by a changeover apparatus and short circuiting the phase connections such that a first braking torque develops at the synchronous machine. In a second state the phase connections are connected to one another by the changeover apparatus and to a resistance, such that a second braking torque develops at the synchronous machine. The changeover apparatus periodically switches between the first and second states at a switching frequency of 10 Hz or higher to produce a pre-settable braking torque at the synchronous machine, with the changeover between the first state and the second state being controlled by a timing element in an unregulated manner.

A method for controlling a braking torque of a drive system and for braking a vehicle includes in a first state connecting phase connections of a synchronous machine to one another by a changeover apparatus and short circuiting the phase connections such that a first braking torque develops at the synchronous machine. In a second state the phase connections are connected to one another by the changeover apparatus and to a resistance, such that a second braking torque develops at the synchronous machine. The changeover apparatus periodically switches between the first and second states at a switching frequency of 10 Hz or higher to produce a pre-settable braking torque at the synchronous machine, with the changeover between the first state and the second state being controlled by a timing element in an unregulated manner.

An apparatus for controlling operation of a walk-behind electric lawn mower equipped with an electric motor, a blade cutter connected to the electric motor and a rechargeable battery mounted connected to the electric motor and a motor driver circuit. In the apparatus, when an instruction to stop the electric motor is inputted, the operation of the motor driver circuit is controlled to output regenerative electric current from three-phase coils of the electric motor. At that time, it is determined whether a rotational speed of the electric motor is equal to or less than a switching rotational speed and when it is, the motor driver circuit is controlled to switch from the regenerative braking to short-circuit braking that short-circuits the three-phase coils of the electric motor.

A brake control system of a motor is provided. When a control circuit intends to brake the motor, the control circuit controls a driver circuit to turn off a first high-side switch and a second high-side switch, and to fully turn on the first low-side switch and the second low-side switch, for a period of time. Then, the control circuit controls the driver circuit to turn off one of the first low-side switch and the second low-side switch, and to continually turn on the other one of the first low-side switch and the second low-side switch, for a period of time. Then, the control circuit controls the driver circuit to turn off the other one of the first low-side switch and the second low-side switch, and to turn on the one of the first low-side switch and the second low-side switch, for a period of time.