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CN-122025472-A - Contactor control system

CN122025472ACN 122025472 ACN122025472 ACN 122025472ACN-122025472-A

Abstract

The invention discloses a contactor control system which comprises a switch circuit, a control circuit, a current detection circuit, a DC/DC converter and a diode, wherein the switch circuit is used for being connected between one end of a contactor coil and a positive electrode of a power supply and is suitable for being switched between an on state and an off state, the control circuit is used for controlling the switch circuit to be switched between the on state and the off state, the current detection circuit is connected with the other end of the contactor coil and is used for detecting current flowing through the contactor coil in real time, the feedback end of the DC/DC converter is connected with the output end of the current detection circuit, and the positive electrode of the diode is connected with the output end of the DC/DC converter, and the negative electrode of the diode is used for being connected with one end of the contactor coil. The control circuit controls the switching circuit to switch to the on state and hold for a predetermined time during a start-up phase of the contactor coil, and controls the switching circuit to switch to the off state during a hold phase of the contactor coil. The invention can ensure that the contactor coil has stable holding current, simplifies the structure and reduces the cost.

Inventors

  • WANG JIANJUN
  • MAO XINHUI
  • SHEN XIANGHU
  • LIU XUEJUN
  • WU YISONG

Assignees

  • 泰科电子(上海)有限公司
  • 泰科电子科技（苏州工业园区）有限公司

Dates

Publication Date
20260512
Application Date
20241112

Claims (20)

  1. 1. A contactor control system, comprising: A switching circuit (1) for connecting between one end (C+) of the contactor coil (7) and the positive pole (V+) of the power supply (6) and adapted to switch between an on-state and an off-state; -a control circuit (2) for controlling the switching circuit (1) to switch between the on-state and the off-state; A current detection circuit (3) connected to the other end (C-) of the contactor coil (7) for detecting in real time the current flowing through the contactor coil (7); A DC/DC converter (4) having a feedback terminal FB connected to the output terminal of the current detection circuit (3), and A diode D2, the anode of which is connected with the output end VDD_ADJ of the DC/DC converter (4), the cathode of which is connected with one end (C+) of the contactor coil (7), During the start-up phase of the contactor coil (7), the control circuit (2) controls the switching circuit (1) to switch to the on state for a predetermined time t to switch on the electrical connection between one end (C+) of the contactor coil (7) and the positive pole (V+) of the power supply (6), During the holding phase of the contactor coil (7), the control circuit (2) controls the switching circuit (1) to switch to the off state to cut off the electrical connection between one end (c+) of the contactor coil (7) and the positive pole (v+) of the power supply (6).
  2. 2. The contactor control system according to claim 1, wherein: during a start-up phase of the contactor coil (7), an output voltage at an output of the DC/DC converter (4) is lower than a supply voltage V1 of the power supply (6), and the diode D2 is used to prevent the supply voltage V1 from being applied in reverse to the output of the DC/DC converter (4).
  3. 3. The contactor control system according to claim 2, wherein: During a start-up phase of the contactor coil (7), the switching circuit (1) switches on an electrical connection between a positive pole (v+) of the power supply (6) and one end (c+) of the contactor coil (7) to supply power to the contactor coil (7) through the power supply (6); The starting current I1 of the contactor coil (7) can be calculated according to the following formula: i1 =v1/Rc, where V1 is the supply voltage of the power supply (6), rc is the resistance of the contactor coil (7).
  4. 4. The contactor control system according to claim 1, wherein: during the holding phase of the contactor coil (7), the switching circuit (1) cuts off the electrical connection between the positive pole (v+) of the power supply (6) and one end (c+) of the contactor coil (7) to supply power to the contactor coil (7) through the output of the DC/DC converter (4).
  5. 5. The contactor control system according to claim 4, wherein: During the holding phase of the contactor coil (7), the current detection circuit (3) detects the holding current I2 flowing through the contactor coil (7) in real time, and the DC/DC converter (4) adjusts the output voltage of the output end of the DC/DC converter (4) according to the holding current I2 detected by the current detection circuit (3) until the holding current I2 detected by the current detection circuit (3) is equal to a preset holding current I.
  6. 6. The contactor control system according to claim 5, wherein: When the holding current I2 detected by the current detection circuit (3) is greater than the predetermined holding current I, the DC/DC converter (4) gradually decreases the output voltage until the holding current I2 detected by the current detection circuit (3) is equal to the predetermined holding current I; When the holding current I2 detected by the current detection circuit (3) is smaller than the predetermined holding current I, the DC/DC converter (4) increases the output voltage step by step until the holding current I2 detected by the current detection circuit (3) is equal to the predetermined holding current I.
  7. 7. The contactor control system according to claim 1, further comprising: And the input end of the LDO circuit (5) is connected with the positive electrode (V+) of the power supply (6), and the output end of the LDO circuit is connected with the power supply ends of the control circuit (2) and the current detection circuit (3) and is used for providing stable power supply voltage for the control circuit (2) and the current detection circuit (3).
  8. 8. The contactor control system according to claim 7, wherein: The control circuit (2) includes: the output end of the comparator U4 is connected with the input end of the switching circuit (1); One end of the resistor R3 is connected with the output end of the LDO circuit (5), and the other end of the resistor R is connected with the inverting input end of the comparator U4; one end of the capacitor C4 is connected with the other end of the resistor R3, and the other end of the capacitor C is grounded; A resistor R4 having one end connected to the output of the LDO circuit (5) and the other end connected to the non-inverting input of the comparator U4, and And one end of the resistor R5 is connected with the other end of the resistor R4, and the other end of the resistor R is grounded.
  9. 9. The contactor control system according to claim 8, wherein: The control circuit (2) further comprises: a capacitor C5, one end of which is connected with the power end of the comparator U4, the other end is grounded, The output end of the LDO circuit (5) is connected with the power end of the comparator U4 and is used for providing stable power supply voltage for the comparator U4.
  10. 10. The contactor control system according to claim 8, wherein: The switching circuit (1) includes: an N-type MOS tube Q2 with a grid connected with the output end of the control circuit (2) and a source grounded, and The grid electrode of the P-type MOS tube Q1 is connected with the drain electrode of the N-type MOS tube Q2, the source electrode of the P-type MOS tube Q1 is connected with the positive electrode (V+) of the power supply (6), and the drain electrode of the P-type MOS tube Q1 is connected with one end (C+) of the contactor coil (7).
  11. 11. The contactor control system according to claim 10, wherein: the switching circuit (1) further comprises: One end of the resistor R7 is connected with the source electrode of the P-type MOS tube Q1, and the other end of the resistor R7 is connected with the grid electrode of the P-type MOS tube Q1; A resistor R8 with one end connected with the output end of the comparator U4 and the other end connected with the grid electrode of the N-type MOS tube Q2, and And one end of the resistor R9 is connected with the other end of the resistor R8 and the grid electrode of the N-type MOS tube Q2, and the other end of the resistor R9 is grounded.
  12. 12. The contactor control system according to claim 11, wherein: the switching circuit (1) further comprises: The positive electrode of the diode D1 is used for being connected with the positive electrode (V+) of the power supply (6), and the negative electrode of the diode D is connected with one end of the resistor R7 and the source electrode of the P-type MOS tube Q1.
  13. 13. The contactor control system according to claim 10, wherein: When the charging time of the capacitor C4 does not reach the predetermined time t, the voltage drop on the capacitor C4 is smaller than the voltage drop on the resistor R5, the voltage at the non-inverting input end of the comparator U4 is higher than the voltage at the inverting input end of the comparator U4, and the output end of the comparator U4 outputs a high level to drive the N-type MOS transistor Q2 and the P-type MOS transistor Q1 to be simultaneously turned on, so that the switch circuit (1) is switched to the on state.
  14. 14. The contactor control system according to claim 10, wherein: When the charging time of the capacitor C4 has reached the predetermined time t, the voltage drop on the capacitor C4 is greater than the voltage drop on the resistor R5, the voltage at the non-inverting input end of the comparator U4 is lower than the voltage at the inverting input end thereof, and the output end of the comparator U4 outputs a low level to drive the N-type MOS transistor Q2 and the P-type MOS transistor Q1 to be simultaneously turned off, so that the switching circuit (1) is switched to the off state.
  15. 15. The contactor control system according to claim 8, wherein: the current detection circuit (3) includes: A sampling resistor R, one end of which is connected with the other end (C-) of the contactor coil (7), the other end of which is grounded, and The positive input end VIN+ of the current detection chip U3 is connected with one end of the sampling resistor R, the negative input end VIN-of the current detection chip is connected with the other end of the sampling resistor R, The output end of the current detection chip U3 is connected with the feedback end FB of the DC/DC converter (4) and is used for feeding back the holding current I2 detected by the current detection chip U3 to the feedback end FB of the DC/DC converter (4).
  16. 16. The contactor control system according to claim 15, wherein: The current detection chip U3 acquires the voltage drop V2 on the sampling resistor R through the positive input end VIN+ and the negative input end VIN-; the holding current I2 detected by the current detection chip U3 can be calculated according to the following formula: i2 =v2/R, where And R is the resistance value of the sampling resistor R.
  17. 17. The contactor control system according to claim 15, wherein: The power end VCC of the current detection chip U3 is connected with the output end of the LDO circuit (5), and the grounding end GND and the reference voltage end REF of the current detection chip U3 are grounded.
  18. 18. The contactor control system according to claim 17, wherein: the current detection circuit (3) further includes: and a capacitor C8 and a capacitor C9, one ends of which are connected to the power supply terminal VCC of the current detection chip U3, and the other ends of which are connected to the ground terminal GND and the reference voltage terminal REF of the current detection chip U3.
  19. 19. The contactor control system according to claim 15, wherein: The DC/DC converter (4) includes: The DC/DC conversion chip U1 has an input voltage pin VIN and an enable pin EN for connection to the positive electrode (V+) of the power supply (6), a power ground pin PGND and an analog ground pin AGND connected to ground, The output end Vout of the DC/DC conversion chip U1 is connected with the anode of the diode D2, and the feedback end FB of the DC/DC conversion chip U1 is connected with the output end of the current detection chip U3.
  20. 20. The contactor control system according to claim 19, wherein: The DC/DC converter (4) further comprises: a capacitor C1 and a capacitor C2, one end of which is connected to the input voltage pin VIN of the DC/DC conversion chip U1 and the other end of which is grounded, and And one end of the capacitor C3 and one end of the capacitor C6 are connected with the output end Vout of the DC/DC conversion chip U1, and the other ends of the capacitor C3 and the capacitor C6 are grounded.

Description

Contactor control system Technical Field The present invention relates to a contactor control system. Background High voltage contactors are a critical device for high voltage distribution, and require a relatively large starting current when the contactor is started, and only a small holding current when the contactor is held. In the prior art, the core bidding advantage of the high-voltage contactor is small size, and the core bidding advantage is matched with the application requirement of miniaturization provided by customers. In the prior art, the holding current of the contactor coil is affected by fluctuations in the supply voltage and the operating temperature, which can lead to fluctuations in the holding current, affecting the reliability of the operation of the contactor. In order to ensure a stable holding current for the contactor coil, voltage compensation and temperature compensation of the contactor control system are required in the prior art. However, the contactor control system based on voltage compensation and temperature compensation has the problems of complex structure and high cost. Disclosure of Invention The present invention is directed to solving at least one of the above-mentioned problems and disadvantages of the prior art. According to one aspect of the present invention, a contactor control system is provided. The contactor control system comprises a switch circuit, a control circuit, a current detection circuit, a DC/DC converter and a diode D2, wherein the switch circuit is used for being connected between one end of a contactor coil and the positive electrode of a power supply and is suitable for being switched between an on state and an off state, the control circuit is used for controlling the switch circuit to be switched between the on state and the off state, the current detection circuit is connected with the other end of the contactor coil and is used for detecting current flowing through the contactor coil in real time, the feedback end FB of the DC/DC converter is connected with the output end of the current detection circuit, and the positive electrode of the diode D2 is connected with the output end of the DC/DC converter, and the negative electrode of the diode D2 is used for being connected with one end of the contactor coil. The control circuit controls the switching circuit to switch to the on state for a predetermined time t to turn on an electrical connection between one end of the contactor coil and the positive electrode of the power supply during a start-up phase of the contactor coil, and controls the switching circuit to switch to the off state to cut off an electrical connection between one end of the contactor coil and the positive electrode of the power supply during a hold-up phase of the contactor coil. According to an exemplary embodiment of the invention, the output voltage of the output of the DC/DC converter is lower than the supply voltage V1 of the power supply during the start-up phase of the contactor coil, and the diode D2 is adapted to prevent the supply voltage V1 from being applied back to the output of the DC/DC converter. According to another exemplary embodiment of the present invention, the switching circuit turns on an electrical connection between the positive electrode of the power supply and one end of the contactor coil to supply power to the contactor coil through the power supply during a start-up phase of the contactor coil; the starting current I1 of the contactor coil can be calculated according to the following formula: i1 =v1/Rc, where V1 is the power supply voltage of the power supply, and Rc is the resistance of the contactor coil. According to another exemplary embodiment of the present invention, the switching circuit cuts off an electrical connection between the positive pole of the power supply and one end of the contactor coil to supply power to the contactor coil through the output terminal of the DC/DC converter during the holding phase of the contactor coil. According to another exemplary embodiment of the present invention, the current detection circuit detects the holding current I2 flowing through the contactor coil in real time during the holding phase of the contactor coil, and the DC/DC converter adjusts the output voltage of the output terminal of the DC/DC converter according to the holding current I2 detected by the current detection circuit until the holding current I2 detected by the current detection circuit is equal to a predetermined holding current I. According to another exemplary embodiment of the present invention, when the holding current I2 detected by the current detection circuit is greater than the predetermined holding current I, the DC/DC converter gradually decreases the output voltage until the holding current I2 detected by the current detection circuit is equal to the predetermined holding current I. When the holding current I2 detected by the current detection circuit is smaller