Power failure holding implementation circuit for relay protection device power supply and relay protection device power supply

Abstract

The utility model discloses a power failure holding implementation circuit for a relay protection device power supply and the relay protection device power supply. The power failure holding implementation circuit comprises an input positive end, an input negative end, a resistor R1, a switching tube Q1, an energy storage capacitor, a driving module, a feedback module and a discharge control module, the input positive end is connected to the drain electrode of the switch tube Q1 through the resistor R1; the source electrode of the switching tube Q1 is connected to the positive electrode of the energy storage capacitor; the input negative end is connected to the cathode of the energy storage capacitor; the driving module is respectively connected to the input positive end, the positive electrode of the energy storage capacitor and the grid electrode of the switch tube Q1 and is used for controlling the conduction of the switch tube Q1; the feedback module is connected to the driving module and the positive electrode and the negative electrode of the energy storage capacitor and used for feeding back voltage at the two ends of the energy storage capacitor to the driving module; the discharge control module is connected to the input positive end and the positive electrode of the energy storage capacitor, and is used for controlling the energy storage capacitor to discharge to the input positive end. According to the utility model, the relay protection device has a long-time output voltage holding function when port voltage sags and is interrupted for a short time, and the circuit is simple and small in size.

Description

Technical Field

[0001] The utility model relates to the technical field of relay protection devices, and more particularly to a power-off retention implementation circuit for a relay protection device power supply and a relay protection device power supply. Background Art

[0002] Relay protection devices generally refer to automated measures and equipment that can promptly issue warning signals to operating personnel on duty, or directly issue trip commands to the controlled circuit breakers to terminate the development of these events when power components (such as generators, lines, etc.) in the power system or the power system itself fail and endanger the safe operation of the power system. The industry inspection standards for relay protection devices require that the device power supply has the function of maintaining the output voltage for a long time when the port voltage is temporarily reduced or interrupted for a short time. To meet this requirement, there are currently two main solutions for the power supply of relay protection devices:

[0003] Solution 1: Use a two-stage power supply topology, increasing the input voltage through the first-stage converter and then reducing the voltage through the second-stage converter. Solution 1 significantly increases the complexity and cost of the device power supply, reduces the reliability and service life of the power supply, and does not meet the relay protection industry's requirements for high reliability and high safety of the device power supply.

[0004] Solution 2: Connect enough filter capacitors in parallel at the input port to store enough energy. Solution 2 increases the number of electrolytic capacitors. Electrolytic capacitors themselves are an important factor restricting the life of the power supply. Connecting more electrolytic capacitors in parallel will obviously greatly reduce the service life of the power supply. At the same time, due to the increase in the capacitance of the port, the design of the port's anti-startup surge current impact circuit becomes difficult. Obviously, this solution is not the best choice.

[0005] Therefore, it is necessary to further improve the power supply of relay protection devices to better solve the problems caused by voltage sag and voltage interruption tests. Utility Model Content

[0006] The purpose of the present utility model is to provide a power-off retention implementation circuit and a relay protection device power supply including the power-off retention implementation circuit to solve the problems mentioned in the above background technology section, namely, to ensure that the device power supply has the output voltage retention function for a long time when the port voltage is temporarily reduced or interrupted for a short time, while making the device power supply have higher reliability, safety and service life.

[0007] According to a first aspect of the present invention, a circuit for implementing power-off retention of a power supply for a relay protection device is provided. The circuit comprises: an input positive terminal, an input negative terminal, a resistor R1, a switch tube Q1, an energy storage capacitor, a drive module, a feedback module, and a discharge control module; the input positive terminal is connected to the drain of the switch tube Q1 via the resistor R1; the source of the switch tube Q1 is connected to the positive electrode of the energy storage capacitor; the input negative terminal is connected to the negative electrode of the energy storage capacitor; the drive module is respectively connected to the input positive terminal, the positive electrode of the energy storage capacitor, and the gate of the switch tube Q1, and is used to control the conduction of the switch tube Q1 when the voltage at the input positive terminal is higher than the positive electrode voltage of the energy storage capacitor; the feedback module is respectively connected to the drive module and the positive and negative electrodes of the energy storage capacitor, and is used to feed back the voltage across the energy storage capacitor to the drive module; the discharge control module is respectively connected to the input positive terminal and the positive electrode of the energy storage capacitor, and is used to cause the energy storage capacitor to discharge toward the input positive terminal when the voltage at the input positive terminal is lower than the positive electrode voltage of the energy storage capacitor.

[0008] Preferably, the switch tube Q1 is an NMOS tube.

[0009] Preferably, the energy storage capacitor is an electrolytic capacitor.

[0010] Preferably, the driving module includes: a resistor R2, a resistor R3, a diode D2, and a voltage regulator ZD1; the two ends of the resistor R2 are respectively connected to the positive input terminal and the positive electrode of the diode D2; the negative electrode of the diode D2 is connected to the gate of the switch tube Q1; the resistor R3 and the voltage regulator ZD1 are connected in parallel between the gate of the switch tube Q1 and the positive electrode of the energy storage capacitor.

[0011] Preferably, the feedback module includes: a resistor R4, a resistor R5, a voltage regulator ZD2, a switch tube Q2, and a diode D3; the two ends of the resistor R4 are respectively connected to the gate and source of the switch tube Q2; the two ends of the resistor R5 are respectively connected to the gate of the switch tube Q2 and the positive electrode of the voltage regulator ZD2; the drain of the switch tube Q2 is connected to the positive electrode of the diode D2 in the driving module; the negative electrode of the voltage regulator ZD2 is connected to the positive electrode of the energy storage capacitor; and the negative electrode of the diode D3 is connected to the negative electrode of the energy storage capacitor.

[0012] Preferably, the switch tube Q2 is an NMOS tube.

[0013] Preferably, the discharge control module includes a diode D1; the anode of the diode D1 is connected to the anode of the energy storage capacitor, and the cathode of the diode D1 is connected to the positive input terminal.

[0014] According to a second aspect of the present invention, a power supply for a relay protection device is provided. The power supply for a relay protection device includes the power-off retention circuit for a relay protection device power supply according to the first aspect of the present invention, and further includes: a protection circuit, an input capacitor, a DC / DC conversion circuit, and an output rectifier and filter circuit, connected in sequence; wherein the positive input terminal and the negative input terminal of the power-off retention circuit for the relay protection device power supply are connected to the positive electrode and the negative electrode of the input capacitor, respectively.

[0015] Preferably, the input capacitor is an electrolytic capacitor.

[0016] Preferably, the protection circuit is an EMC protection circuit.

[0017] Compared with the prior art, the present invention is provided with a power-off retention circuit including an input positive terminal, an input negative terminal, a resistor R1, a switch tube Q1, an energy storage capacitor, a drive module, a feedback module, and a discharge control module; wherein the input positive terminal is connected to the positive electrode of the energy storage capacitor via the resistor R1 and the switch tube Q1, and the input negative terminal is connected to the negative electrode of the energy storage capacitor; the drive module is used to control the conduction of the switch tube Q1 when the voltage at the input positive terminal is higher than the positive electrode voltage of the energy storage capacitor; the feedback module is used to feed back the voltage at both ends of the energy storage capacitor to the drive module; the discharge control module is respectively connected to the positive electrode of the input and the positive electrode of the energy storage capacitor, and is used to discharge the energy storage capacitor to the positive input terminal when the voltage at the input positive terminal is lower than the positive electrode voltage of the energy storage capacitor. In this way, the device power supply can have a long-term output voltage retention function when the port voltage is temporarily reduced or interrupted for a short time. At the same time, the circuit of the present invention is safe and reliable, providing a guarantee for the reliable operation of the relay protection device on site, and the circuit has the advantages of being simple, easy to implement, low cost, and small in size, and is suitable for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the power supply of the relay protection device provided in an embodiment of the present utility model.

[0019] Figure 2 It is a structural diagram of a circuit for realizing power-off retention of a relay protection device power supply provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0020] The present application will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present utility model and are not intended to limit the scope of protection of the present application.

[0021] According to a first aspect of the present utility model, a circuit for realizing power-off retention of a power supply of a relay protection device is provided.

[0022] like Figure 1As shown, the power-off retention circuit 5 can be applied to Figure 1 In the relay protection device power supply shown in FIG. , in addition to the power-off holding circuit, the relay protection device power supply includes a protection circuit 1 , an input capacitor 2 , a DC / DC conversion circuit 3 and an output rectifier filter circuit 4 which are connected in sequence.

[0023] The protection circuit 1 is used to ensure that the device operates in accordance with the requirements of its electromagnetic environment, and will not cause performance degradation, loss of function or damage due to the surrounding electromagnetic environment, nor will it generate excessive electromagnetic energy in the surrounding environment, thereby affecting the normal operation of surrounding devices. Preferably, the protection circuit is an EMC protection circuit.

[0024] The input capacitor 2 is used to store electrical energy and release it when the circuit load changes or when there is a brief power peak, thereby maintaining stable operation of the circuit. It can also suppress high-frequency signals in the circuit. Preferably, the input capacitor is an electrolytic capacitor.

[0025] The DC / DC conversion circuit 3 is used to convert the voltage across the input capacitor into a DC voltage.

[0026] The output rectification and filtering circuit 4 is used to rectify and filter the voltage output by the DC / DC conversion circuit to provide it to the load.

[0027] The power-off retention circuit 5 has a positive input terminal and a negative input terminal, which are connected to the positive and negative terminals of the input capacitor, respectively. When the voltage between the positive and negative input terminals is normally supplied, the power-off retention circuit 5 uses this power to charge and store energy. When the voltage between the positive and negative input terminals is temporarily sagged or interrupted, the power-off retention circuit 5 discharges the power to provide energy to the DC / DC converter circuit to maintain a stable voltage output of the relay protection device power supply.

[0028] Specifically, if Figure 2In one embodiment, the power-off retention implementation circuit 5 includes: an input positive terminal Vin+, an input negative terminal Vin-, a resistor R1, a switch tube Q1, an energy storage capacitor C1, a driving module 51, a feedback module 52, and a discharge control module 53. The input positive terminal is connected to the drain of the switch tube Q1 via the resistor R1. The source of the switch tube Q1 is connected to the positive electrode of the energy storage capacitor C1. The input negative terminal Vin- is connected to the negative electrode of the energy storage capacitor C1. The driving module 51 is respectively connected to the input positive terminal Vin+, the positive electrode of the energy storage capacitor C1 and the gate of the switch tube Q1, and is used to control the conduction of the switch tube Q1 when the voltage of the input positive terminal Vin+ is higher than the positive electrode voltage of the energy storage capacitor C1. The feedback module 52 is respectively connected to the driving module and the positive and negative electrodes of the energy storage capacitor C1, and is used to feed back the voltage across the energy storage capacitor C1 to the driving module. The discharge control module 53 is connected to the positive input terminal Vin+ and the positive electrode of the energy storage capacitor C1 respectively, and is used to discharge the energy storage capacitor C1 to the positive input terminal Vin+ when the voltage of the positive input terminal Vin+ is lower than the positive electrode voltage of the energy storage capacitor C1.

[0029] The switch tube Q1 is an NMOS tube, and the energy storage capacitor C1 is preferably an electrolytic capacitor.

[0030] Furthermore, the driver module 51 includes a resistor R2, a resistor R3, a diode D2, and a voltage regulator diode ZD1. The two ends of the resistor R2 are connected to the positive input terminal Vin+ and the anode of the diode D2, respectively. The cathode of the diode D2 is connected to the gate of the switching transistor Q1. The resistor R3 and the voltage regulator diode ZD1 are connected in parallel between the gate of the switching transistor Q1 and the positive electrode of the energy storage capacitor C1.

[0031] Furthermore, the feedback module 52 includes a resistor R4, a resistor R5, a voltage regulator diode ZD2, a switch transistor Q2, and a diode D3. The two ends of the resistor R4 are connected to the gate and source of the switch transistor Q2, respectively. The two ends of the resistor R5 are connected to the gate of the switch transistor Q2 and the positive electrode of the voltage regulator diode ZD2, respectively. The drain of the switch transistor Q2 is connected to the positive electrode of the diode D2 in the driver module. The negative electrode of the voltage regulator diode ZD2 is connected to the positive electrode of the energy storage capacitor C1. The negative electrode of the diode D3 is connected to the negative electrode of the energy storage capacitor C1.

[0032] Wherein, the switch tube Q2 is an NMOS tube.

[0033] Furthermore, the discharge control module 53 includes a diode D1 , an anode of the diode D1 is connected to the anode of the energy storage capacitor C1 , and a cathode of the diode D1 is connected to the positive input terminal Vin+.

[0034] In this embodiment, the working principle of the circuit for realizing power failure retention of the power supply of the relay protection device is as follows:

[0035] The positive input terminal Vin+ and the negative input terminal Vin- of the power-off retention circuit can usually be connected to the input capacitor in the power supply of the relay protection device.

[0036] When the voltage across energy storage capacitor C1 is lower than the voltage between the positive input terminal Vin+ and the negative input terminal Vin-, a driver module 51 comprising resistor R2, diode D2, resistor R3, and voltage regulator ZD1 turns on switch Q1, thereby charging energy storage capacitor C1 via resistor R1 and switch Q1; R1 is a current-limiting resistor used to control the charging current. Simultaneously, a feedback module 52 comprising voltage regulator ZD2, resistor R5, resistor R4, diode D3, and switch Q2 feeds the voltage across energy storage capacitor C1 back to the driver module, thereby controlling the gate-source voltage of switch Q1 and regulating the voltage across energy storage capacitor C1.

[0037] When the input voltage sags or is interrupted, and the voltage across the energy storage capacitor C1 is higher than the voltage between the input positive terminal Vin+ and the input negative terminal Vin-, the energy storage capacitor C1 provides energy to the external circuit between the input positive terminal Vin+ and the input negative terminal Vin- through the diode D1 in the discharge control module 53 to maintain a stable voltage output of the power supply of the relay protection device, so as to meet the voltage sag and voltage interruption requirements of the relay protection device.

[0038] According to the second aspect of the present invention, a power supply for a relay protection device is provided. Figure 1 In one embodiment, the relay protection power supply includes the power-off retention implementation circuit according to the first aspect of the utility model, and also includes a protection circuit, an input capacitor, a DC / DC conversion circuit and an output rectifier filter circuit connected in sequence.

[0039] The power-off retention implementation circuit has a positive input terminal and a negative input terminal, and the positive input terminal and the negative input terminal are respectively connected to the positive electrode and the negative electrode of the input capacitor.

[0040] Preferably, the input capacitor is an electrolytic capacitor; preferably, the protection circuit is an EMC protection circuit.

[0041] The beneficial effect of the present invention is that, compared with the prior art, a power-off retention circuit is provided, which includes an input positive terminal, an input negative terminal, a resistor R1, a switch tube Q1, an energy storage capacitor, a drive module, a feedback module, and a discharge control module; wherein the input positive terminal is connected to the positive electrode of the energy storage capacitor via the resistor R1 and the switch tube Q1, and the input negative terminal is connected to the negative electrode of the energy storage capacitor; the drive module is used to control the conduction of the switch tube Q1 when the voltage at the input positive terminal is higher than the positive electrode voltage of the energy storage capacitor; the feedback module is used to feed back the voltage at both ends of the energy storage capacitor to the drive module; the discharge control module is respectively connected to the positive electrode of the input and the positive electrode of the energy storage capacitor, and is used to discharge the energy storage capacitor to the positive input terminal when the voltage at the input positive terminal is lower than the positive electrode voltage of the energy storage capacitor. In this way, the device power supply can have a long-term output voltage retention function when the port voltage is temporarily reduced or interrupted for a short time. At the same time, the circuit of the present invention is safe and reliable, providing a guarantee for the reliable operation of the relay protection device on site, and the circuit has the advantages of being simple, easy to implement, low cost, and small in size, and is suitable for promotion and application.

[0042] The applicant of the present utility model has made detailed explanations and descriptions of the implementation examples of the present utility model in conjunction with the drawings in the specification. However, those skilled in the art should understand that the above implementation examples are only preferred implementation plans of the present utility model, and the detailed description is only to help readers better understand the spirit of the present utility model, and is not a limitation on the scope of protection of the present utility model. On the contrary, any improvements or modifications based on the inventive spirit of the present utility model should fall within the scope of protection of the present utility model.

Claims

1. A circuit for realizing power-off retention of a relay protection device power supply, characterized in that: include: Input positive terminal, input negative terminal, resistor R1, switch tube Q1, energy storage capacitor, drive module, feedback module, discharge control module; The positive input terminal is connected to the drain of the switch tube Q1 via the resistor R1; The source of the switch tube Q1 is connected to the positive electrode of the energy storage capacitor; The negative input terminal is connected to the negative electrode of the energy storage capacitor; The driving module is respectively connected to the input positive terminal, the positive electrode of the energy storage capacitor and the gate of the switch tube Q1, and is used to control the conduction of the switch tube Q1 when the voltage of the input positive terminal is higher than the positive electrode voltage of the energy storage capacitor; The feedback module is connected to the driving module and the positive electrode and the negative electrode of the energy storage capacitor respectively, and is used to feed back the voltage across the energy storage capacitor to the driving module; The discharge control module is connected to the input positive terminal and the positive electrode of the energy storage capacitor respectively, and is used to discharge the energy storage capacitor to the input positive terminal when the voltage of the input positive terminal is lower than the positive electrode voltage of the energy storage capacitor.

2. The power-off retention circuit for a relay protection device power supply according to claim 1, characterized in that: The switch tube Q1 is an NMOS tube.

3. The power-off retention circuit for a relay protection device power supply according to claim 1, characterized in that: The energy storage capacitor is an electrolytic capacitor.

4. The power-off retention circuit for a relay protection device power supply according to claim 1, characterized in that: The driving module includes: a resistor R2, a resistor R3, a diode D2, and a voltage regulator ZD1; The two ends of the resistor R2 are connected to the positive input terminal and the positive electrode of the diode D2 respectively; The cathode of the diode D2 is connected to the gate of the switch tube Q1; The resistor R3 and the voltage regulator ZD1 are connected in parallel between the gate of the switch tube Q1 and the positive electrode of the energy storage capacitor.

5. The power-off retention circuit for a relay protection device power supply according to claim 4, characterized in that: The feedback module includes: resistor R4, resistor R5, voltage regulator ZD2, switch Q2, and diode D3; The two ends of the resistor R4 are connected to the gate and source of the switch tube Q2 respectively; The two ends of the resistor R5 are connected to the gate of the switch tube Q2 and the positive electrode of the voltage regulator tube ZD2 respectively; The drain of the switch tube Q2 is connected to the anode of the diode D2 in the driving module; The negative electrode of the voltage regulator tube ZD2 is connected to the positive electrode of the energy storage capacitor; The cathode of the diode D3 is connected to the cathode of the energy storage capacitor.

6. The power-off retention circuit for a relay protection device power supply according to claim 5, characterized in that: The switch tube Q2 is an NMOS tube.

7. The power-off retention circuit for a relay protection device power supply according to claim 1, characterized in that: The discharge control module includes a diode D1 ; the anode of the diode D1 is connected to the anode of the energy storage capacitor, and the cathode of the diode D1 is connected to the positive input terminal.

8. A power supply for a relay protection device, characterized in that: It comprises a power-off retention implementation circuit for a relay protection device power supply according to any one of claims 1 to 7, and also comprises: a protection circuit, an input capacitor, a DC / DC conversion circuit and an output rectifier and filter circuit connected in sequence; wherein the input positive terminal and the input negative terminal of the power-off retention implementation circuit for the relay protection device power supply are respectively connected to the positive electrode and the negative electrode of the input capacitor.

9. The power supply for relay protection device according to claim 8, characterized in that: The input capacitor is an electrolytic capacitor.

10. The power supply for relay protection device according to claim 8, characterized in that: The protection circuit is an EMC protection circuit.

Images