Bidirectional freewheeling circuit for direct current motor
Disclosed in the present disclosure is a bidirectional freewheeling circuit for a direct current motor. Two unidirectional freewheeling circuits are connected in parallel between a power supply and the direct current motor, the two unidirectional freewheeling circuits are a unidirectional freewheeling circuit I and a unidirectional freewheeling circuit II in sequence, and the unidirectional freewheeling circuit includes a diode and an equivalent switch connected in series to the diode. Conduction directions of the diodes in the two the unidirectional freewheeling circuits are opposite, when a voltage applied to both ends of the motor satisfies Ua>Ub, the equivalent switch I is turned on, the equivalent switch II is turned off, and when the voltage applied to both ends of the direct current motor satisfies Ua<Ub, the equivalent switch II is turned on, and the equivalent switch I is turned off.
1 . A bidirectional freewheeling circuit for a direct current motor, wherein two unidirectional freewheeling circuits are connected in parallel between a power supply and the direct current motor, the two unidirectional freewheeling circuits are a first unidirectional freewheeling circuit and a second unidirectional freewheeling circuit in sequence, each one of the first the unidirectional freewheeling circuit and the second unidirectional freewheeling circuit comprises a diode and an equivalent switch connected in series to the diode, conduction directions of the diodes in the two unidirectional freewheeling circuits are opposite, wherein when a voltage applied to both ends of the direct current motor satisfies Ua>Ub, the equivalent switch in the first unidirectional freewheeling circuit is turned on, the equivalent switch in the second unidirectional freewheeling circuit is turned off, and when the voltage applied to both ends of the direct current motor satisfies Ua<Ub, the equivalent switch in the second unidirectional freewheeling circuit is turned on, and the equivalent switch in the first unidirectional freewheeling circuit is turned off, wherein Ua is a first voltage signal applied to a first end of the direct current motor, and Ub is a second voltage signal applied to a second end of the direct current motor.
2 . The bidirectional freewheeling circuit for a direct current motor according to claim 1 , wherein the equivalent switch in each one of the two unidirectional freewheeling circuits comprises a capacitor and at least one optical switch connected in parallel to the capacitor, a Schottky diode is arranged on a charging loop of the capacitor and the power supply, wherein the power supply charges the capacitor by means of the Schottky diode when the power supply is powered on, the capacitor is connected in parallel to a voltage-regulator diode, and meanwhile, multiple paths of optical switches are in an on state, when the power supply is powered off, the capacitor discharges to the multiple paths of the optical switches for supplying power, the multiple paths of optical switches are still in the on state, and the direct current motor forms a freewheeling loop by means of the diodes and the optical switches.
3 . The bidirectional freewheeling circuit for a direct current motor according to claim 1 , wherein the first unidirectional freewheeling circuit comprises a first unidirectional capacitor charging loop, a first unidirectional capacitor discharge loop and a first unidirectional freewheeling loop, wherein the first unidirectional capacitor charging loop comprises the power supply, a first resistor, a seventh Schottky diode and a second capacitor, in the first unidirectional capacitor charging loop, the second capacitor is connected in parallel to a thirteenth voltage-regulator diode and a fourteenth voltage-regulator diode, the first unidirectional capacitor discharge loop comprises a discharge loop of a first optical switch a discharge loop of a sixth optical switch, the discharge loop of the first optical switch comprises the second capacitor, a resistor R 2 and the first optical switch U 1 , the discharge loop of the sixth optical switch comprises the second capacitor, a seventh resistor and the sixth optical switch, the first unidirectional freewheeling loop comprises a freewheeling loop of the first optical switch and a freewheeling loop of the sixth optical switch, the freewheeling loop of the first optical switch comprises the direct current motor, a fifth diode, a sixteenth diode and the first optical switch, and the freewheeling loop of the sixth optical switch comprises direct current motor, the diode, the sixteenth diode D 16 and the sixth optical switch.
4 . The bidirectional freewheeling circuit for a direct current motor according to claim 1 , wherein the second unidirectional freewheeling circuit comprises a second unidirectional capacitor charging loop, a second unidirectional capacitor discharge loop, and a second unidirectional freewheeling loop, wherein the second unidirectional capacitor charging loop comprises the power supply, a tenth resistor, a twelfth Schottky diode and a first capacitor, in the second unidirectional capacitor charging loop, the first capacitor is connected in parallel to a fourth voltage-regulator diode and a fifth voltage-regulator diode, the second unidirectional capacitor discharge loop comprises a discharge loop of a second optical switch and a discharge loop of an eighth optical switch, the discharge loop of the second optical switch comprises the capacitor, a fourth resistor and the second optical switch, the discharge loop of the eighth optical switch comprises the capacitor, a ninth resistor and the eighth optical switch, the second unidirectional freewheeling loop comprises a freewheeling loop of the second optical switch and a freewheeling loop of the eighth optical switch, the freewheeling loop of the second optical switch comprises the direct current motor, a first diode, a second diode and the second optical switch, and the freewheeling loop of the eighth optical switch comprises the direct current motor, the first diode D 1 , the second diode D 2 and the eighth optical switch.
5 . The bidirectional freewheeling circuit for a direct current motor according to claim 3 , wherein when the power supply is powered off, stored energy on the second capacitor is higher than a threshold voltage of a control terminal of the first optical switch, and the stored energy on the second capacitor is also higher than a threshold voltage of a control terminal of the sixth optical switch.
6 . The bidirectional freewheeling circuit for a direct current motor according to claim 4 , wherein stored energy on the first capacitor is higher than a threshold voltage of a control terminal of the second optical switch, and the stored energy on the first capacitor is also higher than a threshold voltage of a control terminal of the eighth optical switch.