Device and method for motor braking

A motor braking device for a N-phase brushless motor, comprising:

• a switching circuit adapted to connect the N-phase brushless motor to a power supply, the switching circuit comprising a high side switch group and a low side switch group, each of the high side switch group and the low side switch group comprising N switching elements;
• a capacitor circuit arranged on an input side of the switching circuit;
• and
• a control unit configured to control the switching circuit to brake the motor based on occurrence of an event, the event chosen from a group consisting of release of a trigger by a user, or occurrence of a predetermined condition as detected by a sensor;
• wherein the control unit is configured to, upon occurrence of the event, turn off all the switching elements of the high side switch group and drive all the switching elements of the low side switch group using Power Width Modulation (PWM) control until a speed of the motor drops to a predetermine speed during a first period, and then maintain all the switching elements of the high side switch group in an off-state and drive all the switching elements of the low side switch group to an on-state during a second period;
• and
• wherein when the power supply is removed from the motor braking device during braking, the control unit is configured to detect when a bus voltage is higher than a predetermined bus voltage, and to stop braking while being shortly powered by the capacitor circuit in response.

A motor braking method for a N-phase brushless motor, comprising:

• detecting a first event chosen from a group consisting of release of a trigger by a user, and occurrence of a predetermined condition as detected by a sensor, the trigger being actuated by a user to turn on/off a power supply;
• and
• controlling a switching circuit to brake the N-phase brushless motor, the switching circuit being adapted to connect the N-phase brushless motor to the power supply, the switching circuit comprising a high side switch group and a low side switch group, each of the high side switch group and the low side switch group comprising N switching elements,
• wherein the switching circuit is controlled to brake the motor by switching all the switching elements of one of the high side switch group or the low side switch group to an on-state, and simultaneously switching all the switching elements of the other one of the high side switch group and the lower side switch group to an off-state;
• and
• wherein when the power supply is removed during braking, the control unit is configured to detect when a bus voltage is higher than a predetermined bus voltage, and to stop braking while being shortly powered by a capacitor circuit in response.

A motor braking method for a N-phase brushless motor, comprising:

• detecting a first event chosen from a group consisting of release of a trigger by a user, and occurrence of a predetermined condition as detected by a sensor, the trigger being actuated by a user to turn on/off a power supply;
• and
• controlling a switching circuit to brake the N-phase brushless motor, the switching circuit being adapted to connect the N-phase brushless motor to the power supply, the switching circuit comprising a high side switch group and a low side switch group, each of the high side switch group and the low side switch group comprising N switching elements,
• wherein the switching circuit is controlled to brake the motor by turning off all the switching elements of the high side switch group and driving all the switching elements of the low side switch group using Power Width Modulation (PWM) control until a speed of the motor drops to a predetermine speed during a first period, and then maintaining all the switching elements of the high side switch group in an off-state and driving all the switching elements of the low side switch group to an on-state during a second period;
• and
• wherein when the power supply is removed during braking, the control unit is configured to detect when a bus voltage is higher than a predetermined bus voltage, and to stop braking while being shortly powered by a capacitor circuit in response.