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CN-122025474-A - Relay driving circuit of power supply equipment and control method thereof

CN122025474ACN 122025474 ACN122025474 ACN 122025474ACN-122025474-A

Abstract

The invention discloses a relay driving circuit of power supply equipment and a control method thereof, which belong to the technical field of power supply equipment, wherein a change-over switch comprises a first branch and a second branch, the output ends of the first branch and the second branch are intersected, the coil of a first relay unit, the coil of the second relay unit and the contact sides of the second switch are connected in series with two ends of a power supply, the coil of the second relay unit and the contact sides of the second switch are connected in series with two ends of the power supply, the coil of the first relay unit and the contact sides of the first switch are connected in series with two ends of the power supply, and the common end of the coil of the first relay unit and the contact sides of the first switch is connected to the control end of the change-over switch so as to drive the on-off of the first branch and the second branch, and realize the switching of coil current paths of the first relay unit and the second relay unit. The control method comprises three working modes. The invention can effectively reduce the power consumption of the relay after the relay is attracted and reduce electromagnetic interference.

Inventors

  • ZHANG TAO
  • SHI WEIWEI
  • QU ZHAOCHENG
  • WANG ZHIYANG

Assignees

  • 南京康尼新能源汽车零部件有限公司

Dates

Publication Date
20260512
Application Date
20260310

Claims (8)

  1. 1. The relay driving circuit of the power supply equipment is characterized by comprising a power supply source, a first relay unit, a first switch, a second relay unit, a second switch and a change-over switch, wherein the change-over switch comprises a first branch and a second branch, and output ends of the first branch and the second branch are intersected; the coil of the first relay unit, the coil of the first branch circuit, the coil of the second relay unit and the contact side of the second switch are connected in series to two ends of the power supply; The second branch, the coil of the second relay unit and the contact side of the second switch are connected in series to two ends of the power supply; the coil of the first relay unit and the contact side of the first switch are connected in series with the two ends of the power supply; the coil of the first relay unit and the common end of the contact side of the first switch are connected to the control end of the change-over switch, so that the first branch and the second branch are driven to be switched on and off, and the coil current paths of the first relay unit and the second relay unit are switched.
  2. 2. The relay driving circuit of power supply equipment according to claim 1, wherein the first relay unit or the second relay unit is composed of a single relay or a plurality of parallel relays, and the coils of the relays are connected with protection devices in parallel, and the protection devices adopt diodes or series combination of diodes and resistors.
  3. 3. The relay driving circuit for power supply equipment according to claim 1, wherein the first switch and the second switch each comprise a transistor, a control terminal of the transistor of the first switch is connected to a first control signal source, two contacts on a contact side are connected to a ground line and a coil of the first relay unit, respectively, a control terminal of the transistor of the second switch is connected to a second control signal source, and two contacts on the contact side are connected to the ground line and the coil of the second relay unit, respectively.
  4. 4. The power supply relay driving circuit according to claim 3, wherein the first switch and the second switch each comprise a current limiting resistor and a pull-down resistor, the current limiting resistor is connected to the control terminal of the transistor, and the control terminal of the transistor is grounded via the pull-down resistor.
  5. 5. The relay driving circuit of a power supply apparatus according to claim 1, wherein the change-over switch includes a transistor, a voltage regulator tube, a resistor, and a diode, the diode constitutes a first branch, connected between coils of the first relay unit and the second relay unit, two contacts on a contact side of the transistor constitute a second branch, connected to the power supply source and the coils of the second relay unit, respectively, and a common terminal of the diode and the coils of the first relay unit is connected to a control terminal of the transistor via the voltage regulator tube and the resistor.
  6. 6. A power supply apparatus comprising the power supply apparatus relay driving circuit according to any one of claims 1 to 5.
  7. 7. A control method applicable to the relay driving circuit of a power supply apparatus as claimed in any one of claims 1 to 5, comprising: Starting driving, and controlling the first switch and the second switch to be conducted; a drive process comprising: the first mode is to control the first switch to be turned off so as to realize voltage switching; The second mode is to drive the first switch to be turned on and off through the PWM control signal so as to realize voltage switching and PWM injection current mixed driving; The third mode is to control the first switch to be turned off, and the second switch is excited to be turned on and off by the PWM control signal, so that voltage switching and PWM current reduction hybrid driving are realized; And after the driving is finished, the first switch and the second switch are controlled to be turned off.
  8. 8. The control method of the relay driving circuit of the power supply apparatus according to claim 7, wherein the first mode, the second mode, and the third mode are freely switchable.

Description

Relay driving circuit of power supply equipment and control method thereof Technical Field The invention relates to the technical field of power supply equipment, in particular to a relay driving circuit of power supply equipment and a control method thereof. Background The relay is an automatic switching element with an isolation function, belongs to safety key components of power supply equipment, has been widely applied in the field of new energy automobiles, is usually used for 2 or more relays, and needs higher voltage when the relay is in suction through low-voltage control high-voltage on-off, and after the relay is in suction, 30% -80% of voltage is usually needed to keep contacts closed, and some relays can definitely require that the contacts are not reduced in driving voltage after the contact is in suction, and do not allow long-term power-on use, prevent severe coil heating and reduce the service life of the relay. At present, because of the safety requirement of the power supply equipment of the electric automobile, the power consumption of a coil needs to be reduced after the relay is attracted, and the scheme of general sampling is as follows: 1. the relay is controlled by two transistors, one transistor controls the relay to be attracted, the other transistor controls the series resistance of the relay coil to conduct voltage division so that the relay keeps attracted, and the heat of the relay coil is reduced. 2. The relay is controlled by the main power supply, the auxiliary power supply and two transistors, one transistor controls the main power supply to provide rated voltage to enable the relay to be attracted, the other transistor controls the auxiliary power supply to provide holding voltage to enable the relay to be kept attracted, the heat of a coil of the relay is reduced, the auxiliary power supply for the scheme needs a buck circuit for reducing power consumption, the circuit cost is high, the output voltage is fixed, and the circuit can generate larger electromagnetic interference when operated at high frequency. 3. The relay reduces the relay coil current through reducing the relay coil current, the transistor controls the relay to be attracted, and the relay coil current is reduced through a PWM control mode, so that the heat quantity of the relay coil is reduced, but the method can cause the increase of the switching power loss and the serious electromagnetic interference due to the PWM control of the transistor, and the switching power loss and the electromagnetic interference generated by using a plurality of relays can be multiplied. The power supply equipment reduces the power consumption of the coil after the relay is attracted, and in the scheme 1, the voltage of the relay is reduced through resistor voltage division to reduce the heat of the coil, but one path of control is needed to be added, and the resistor generates additional power consumption. In the scheme 2, the relay voltage is reduced through double power supplies to reduce the coil heat, but one-way control is needed to be added, the auxiliary buck circuit is high in cost, the voltage is fixed, and larger electromagnetic interference can be generated. Scheme 3 reduces relay current through PWM control mode reduces coil heat, but can bring transistor switching power loss and serious electromagnetic interference, and switching power loss and electromagnetic interference that use a plurality of relays can doubly increase. Therefore, it is necessary to design a relay driving circuit of a power supply device and a control method thereof, which have the advantages of simple circuit, flexible use, low power consumption and small electromagnetic interference influence, thereby reducing the cost and improving the practicability. Disclosure of Invention The invention aims to overcome the defects in the prior art, provides a relay driving circuit of power supply equipment and a control method thereof, and solves the technical problems of three existing schemes provided in the background art. In order to achieve the above purpose, the invention is realized by adopting the following technical scheme: In a first aspect, the invention provides a relay driving circuit of power supply equipment, which comprises a power supply, a first relay unit, a first switch, a second relay unit, a second switch and a change-over switch, wherein the change-over switch comprises a first branch and a second branch, and output ends of the first branch and the second branch are intersected; the coil of the first relay unit, the coil of the first branch circuit, the coil of the second relay unit and the contact side of the second switch are connected in series to two ends of the power supply; The second branch, the coil of the second relay unit and the contact side of the second switch are connected in series to two ends of the power supply; the coil of the first relay unit and the contact side of the first switch are connected in series with