A control circuit and method for reducing the temperature of a three-phase resistor-capacitor power supply TVS tube, and a resistor-capacitor power supply

Abstract

The application provides a control circuit and method for reducing the temperature of a three-phase resistance-capacitance power supply TVS tube and a resistance-capacitance power supply. The resistance-capacitance power supply comprises a main power supply module, a three-phase rectifier module and a corresponding TVS tube of each phase; the control circuit comprises a control chip and a three-phase control module; each phase control module comprises a power supply switch unit and a freewheeling switch unit; the control chip is used for outputting a high level only through a control pin of one phase based on the three-phase measurement voltage of a three-phase meter, at this time, the power supply switch unit of the phase is turned on and the freewheeling switch unit is turned off, the resistance-capacitance power supply of the phase is used for supplying power to the main power supply module, and the TVS tube is not caused to heat; meanwhile, the control pins of the other two phases output low levels, the power supply switch units of the corresponding phases are turned off, the freewheeling switch units are turned on, the positive and negative poles of the rectifier module form a low impedance loop through the freewheeling switch units, and the current does not flow through the TVS tube, so that the TVS tube works at a suitable temperature and the service life of the three-phase meter is prolonged.

Description

Technical Field

[0001] This invention relates to the field of RC power supply technology, and in particular to a control circuit, control method, and RC power supply for reducing the temperature of the TVS tube in a three-phase RC power supply. Background Technology

[0002] Smart meters are an important component of the nation's robust smart grid construction. The reliable operation and metering of smart meters are crucial to the stability of the power grid. Reducing the temperature of the meter components and maintaining a suitable temperature is an important foundation for the stable and reliable operation of smart meters.

[0003] Three-phase energy meters with RC power supply (hereinafter referred to as three-phase meters) can not only meet the metering of three-phase energy, but also have advantages such as light weight, low power consumption and low cost compared with conventional three-phase meters. However, in practical applications, the power supply device TVS tube in the RC three-phase meter often has the disadvantage of high temperature, which will affect the service life of the device. This device is a key component of the power supply, and once it is damaged, it will directly affect the life of the three-phase meter. Summary of the Invention

[0004] This invention provides a control circuit, control method, and RC power supply for reducing the temperature of the TVS diode in a three-phase RC power supply, thereby solving the problem of high TVS diode temperature in existing RC power supplies.

[0005] In a first aspect, embodiments of the present invention provide a control circuit for reducing the temperature of TVS tubes in a three-phase RC power supply, wherein the RC power supply includes a downstream main power supply module, a three-phase rectifier module, and corresponding TVS tubes.

[0006] The control circuit includes: a control chip and a three-phase control module; each phase control module includes a power supply switch unit and a freewheeling switch unit.

[0007] Each corresponding TVS diode is connected in parallel between the positive and negative input terminals of the corresponding phase rectifier module; the first terminal of each phase power supply switch unit and the first terminal of each freewheeling switch unit are respectively connected to the positive output terminal of the corresponding phase rectifier module; the control terminal of each phase power supply switch unit and the control terminal of each phase freewheeling switch unit are respectively connected to the corresponding phase control pin of the control chip; the second terminal of each phase power supply switch unit is respectively connected to the input terminal of the subsequent main power supply module; the second terminal of each phase freewheeling switch unit is respectively connected to the negative output terminal of the corresponding phase rectifier module; the impedance of the freewheeling switch unit is lower than the impedance of the corresponding TVS diode;

[0008] The control chip is used to control one phase control pin to output a high-level signal and the other two phase control pins to output low-level signals based on the three-phase metering voltage of the three-phase meter.

[0009] The phase power supply switch unit is turned on when a high level signal is connected, and is turned off when a low level signal is connected; the phase freewheeling switch unit is turned off when a high level signal is connected, and is turned on when a low level signal is connected.

[0010] In a second aspect, the embodiments of the present application provide a control method for reducing the temperature of a TVS tube of a three-phase resistance-capacitance power supply, applied to the control circuit in the first aspect; comprising:

[0011] Obtaining three-phase metering voltages of a three-phase meter;

[0012] According to the three-phase metering voltages of the three-phase meter, a high level signal is outputted from one phase control pin, and low level signals are outputted from the other two phase control pins.

[0013] In a third aspect, the embodiments of the present application provide a resistance-capacitance power supply comprising the control circuit in any one of the first aspect.

[0014] The embodiments of the present application provide a control circuit, a control method and a resistance-capacitance power supply for reducing the temperature of a TVS tube of a three-phase resistance-capacitance power supply. The resistance-capacitance power supply comprises a later-stage main power supply module, a three-phase rectifier module and a corresponding TVS tube of each phase. The control circuit comprises a control chip and a three-phase control module. Each phase control module comprises a power supply switch unit and a freewheeling switch unit. The control chip is configured to output a high level signal from only one phase control pin based on three-phase metering voltages of a three-phase meter. At this time, the power supply switch unit of the phase is turned on, and the freewheeling switch unit is turned off. The later-stage main power supply module is powered by the resistance-capacitance power supply of the phase. The current flowing through the TVS tube is the difference between the resistance-capacitance power supply loop current and the later-stage load current. This current is small and will not cause the TVS tube to heat up. At the same time, the other two phase control pins output low level signals, so that the corresponding phase power supply switch unit is turned off, and the freewheeling switch unit is turned on. The positive and negative electrodes of the rectifier module form a low impedance loop through the freewheeling switch unit. The current mainly flows through the freewheeling switch unit, avoiding flowing through the TVS tube, thereby ensuring that the TVS tube works at a suitable temperature and prolonging the service life of the three-phase meter. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative labor based on these drawings.

[0016] Figure 1 is a structural schematic diagram of the control circuit for reducing the temperature of a TVS tube of a three-phase resistance-capacitance power supply provided by the embodiments of the present application;

[0017] Figure 2is a structural schematic diagram of a conventional three-phase resistive-capacitive power supply provided by the embodiment of the present application;

[0018] Figure 3 is an example diagram of the position of the control circuit for reducing the temperature of the TVS tube of the three-phase resistive-capacitive power supply in the three-phase resistive-capacitive power supply provided by the embodiment of the present application;

[0019] Figure 4 is a flowchart of the control method for reducing the temperature of the TVS tube of the three-phase resistive-capacitive power supply provided by the embodiment of the present application;

[0020] Figure 5 is a schematic diagram of a terminal provided by the embodiment of the present application. DETAILED DESCRIPTION

[0021] In the following description, specific details are set forth, such as particular system configurations, techniques, etc., in order to provide a thorough understanding of the embodiments of the present application. However, persons skilled in the art will understand that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

[0022] In order to make the objects, technical solutions, and advantages of the present application clearer, the following will be described by specific embodiments in conjunction with the accompanying drawings.

[0023] Figure 1 is a structural schematic diagram of the control circuit for reducing the temperature of the TVS tube of the three-phase resistive-capacitive power supply provided by the embodiment of the present application. The resistive-capacitive power supply includes a post-stage main power supply module, a three-phase rectification module, and a corresponding TVS tube of each phase.

[0024] As shown in Figure 1 , the control circuit includes a control chip and a three-phase control module 100; each phase control module 100 includes a power supply switch unit 20 and a freewheeling switch unit 10;

[0025] The corresponding TVS tube of each phase is connected in parallel between the positive and negative input terminals of the corresponding phase rectification module; the first end of each phase power supply switch unit 20 and the first end of each phase freewheeling switch unit 10 are respectively connected to the positive output terminal of the corresponding phase rectification module; the control end of each phase power supply switch unit 20 and the control end of each phase freewheeling switch unit 10 are respectively connected to the corresponding phase control pin of the control chip; the second end of each phase power supply switch unit 20 is respectively in communication with the input terminal of the post-stage main power supply module; the second end of each phase freewheeling switch unit 10 is respectively connected to the negative output terminal of the corresponding phase rectification module; the impedance of the freewheeling switch unit 10 is lower than that of the TVS tube;

[0026] The control chip is configured to control one phase control pin to output a high level signal and the other two phase control pins to output low level signals according to three-phase metering voltage of the three-phase meter.

[0027] The phase power supply switch unit 20 is turned on when a high level signal is input and is turned off when a low level signal is input; the phase freewheeling switch unit 10 is turned off when a high level signal is input and is turned on when a low level signal is input.

[0028] In the embodiment, the TVS (Transient Voltage Suppressor), commonly known as transient diode or surge protection diode, is an electronic protection element specially used for suppressing transient overvoltage in a circuit, and mainly functions to protect sensitive electronic devices from lightning, electrostatic discharge (ESD), power switch noise, inductive load switching and other transient high voltage impacts.

[0029] The resistance-capacitance power supply, more accurately called a capacitance step-down power supply or resistance-capacitance step-down power supply, is a simple and low-cost power supply solution that uses the capacitive reactance of a capacitor to limit alternating current and obtains the required direct current voltage through rectification, filtering and voltage stabilization. Figure 2 The resistance-capacitance power supply generally includes a rear-stage main power supply module, an alternating current input module corresponding to each phase, a resistance-capacitance step-down module, a rectification module and a voltage stabilization module.

[0030] Specifically, taking the A phase as an example, the alternating current input module includes a first current-limiting resistor RV1, which is connected in parallel between the positive and negative poles Un and Ua of the alternating current input end, and is used to limit the surge current of the alternating current input to avoid impacting the rectification module.

[0031] The alternating current input module further includes a TVS tube TVSA2, which is connected in parallel to the alternating current input end of the rectification module PD1 to suppress the line-to-line alternating current surge and protect the internal rectification bridge of PD1.

[0032] The rear-stage main power supply module includes a first filter capacitor CP3, a TVS tube, a diode DA3, a capacitor CP2, a DCDC converter U1 and a capacitor CP1.

[0033] Specifically, as shown in Figure 2 The output positive poles ZV of the rectification modules corresponding to each phase are connected to each other, and the output negative poles ZD are connected to each other, thereby forming a common positive connection point ZV and a common negative connection point ZD.

[0034] Then, in the post-stage main power supply module, the first filter capacitor CP3 and the TVS tube are connected in parallel between the positive connection point ZV and the negative connection point ZD, the anode of the diode DA3 is connected with the positive connection point ZV, the cathode is connected with the first end of the capacitor CP2 and the input end of the DCDC converter U1 respectively, the output end of the DCDC converter U1 is connected with the power supply VCC and the first end of the capacitor CP1 respectively, the second end of the capacitor CP2, the second end of the capacitor CP1, the negative connection point ZD and the ground end of the DCDC converter U1 are all grounded GND.

[0035] Specifically, the capacitor CP3 is used to filter out low-frequency ripples in direct current; the TVS tube TVSA1 clamps the direct current side surge and protects U1. The diode DA3 is used to prevent reverse voltage, and the capacitor CP2 further filters out high-frequency ripples; U1 converts high-voltage direct current into stable low-voltage to supply power to the main control circuit, and the above-mentioned loop constitutes a main power supply loop of the blocking capacitor power supply, which supplies power to the MCU (Microcontroller Unit), memory, display and the like.

[0036] The blocking capacitor power supply further comprises a phase measurement power supply loop; the phase measurement power supply loop comprises a second current-limiting resistor, a first sub-loop capacitor, a sub-loop diode, a sub-loop TVS tube, a second sub-loop capacitor, a voltage stabilizer and a third sub-loop capacitor.

[0037] Also taking phase A as an example, as shown in FIG. 2, the phase A measurement power supply loop comprises a second current-limiting resistor RA10, a first sub-loop capacitor CA10, a sub-loop diode DA4, a sub-loop TVS tube TVSA1, a second sub-loop capacitor CA2, a voltage stabilizer UA1 and a third sub-loop capacitor CA3. Among them, the second current-limiting resistor RA10 and the first sub-loop capacitor CA10 limit the current by using the capacitor reactance to reduce the alternating voltage to low voltage. The diode DA4 rectifies the alternating current to direct current; TVSA1 is used to suppress the direct current side spike; the capacitor CA2 is used for filtering, and UA1 is used for voltage stabilizing output VCC_A to supply power to the A-phase measurement chip, independently GND_A, avoiding interference from the main loop, and improving the measurement accuracy.

[0038] According to the above structure, the three-phase independent blocking capacitor power supplies power to the three-phase meter, avoiding mutual interference; the metering chip detects Ua, Ub and Uc separately, meeting the separate phase metering requirement of the three-phase meter. The blocking capacitor power supply circuit of each phase can be simplified to be equivalent to a circuit formed by the series connection of the safety capacitor impedance Uc and the load impedance Ur, the total impedance Z = Uc + Ur, the current I in the whole circuit is U / Z, U is the voltage Uc in the circuit, which is much larger than Ur. The high impedance generated by the safety capacitor divides most of the voltage, and the remaining small part of the voltage is applied across the load. Since the impedance Z in the whole AC circuit is determined, the current I in the whole circuit is determined. Therefore, when the current I0 required by the load is less than the determined current I, the remaining current will pass through the transient voltage suppression (TVS) diode or the zener diode. The application uses a TVS tube for illustration. Generally, a suitable TVS tube can be selected according to the single-phase power supply requirement to meet the requirement.

[0039] When the three-phase meter requires single-phase starting voltage U0 power supply, the electric energy meter can work normally. The starting voltage is generally 0.7 times the rated voltage Un, so I0 = 0.7I. When single-phase rated voltage is supplied, the excess current, about 0.3I, will pass through the TVS tube. At this time, the TVS tube generates normal heat, and the temperature is within the normal range. However, when three-phase AC voltage is applied at the same time, the current in each circuit is basically determined, and the current in the main circuit is the superposition of the currents in the ABC phase AC circuits. When the rated voltage is applied to the ABC phase at the same time, the ZV and ZD connected after the rectifier module of the ABC phase are connected together and flow into the later-stage main power supply module. The later-stage main power supply module mainly supplies power to the MCU, the memory and the display, and the current required by the later-stage main power supply module is basically constant in normal state. Therefore, the excess current of about 2.3I will be discharged through the TVS tube, and the heat generated by the TVS tube will be very large. When the working environment temperature of the three-phase meter is normal temperature, the temperature will rise to about 68℃. When the working environment temperature is 70℃, the temperature of the TVS tube is about 110℃, and the TVS tube can still work normally, but it will cause the tube to age prematurely, thereby reducing the service life of the TVS tube and seriously affecting the stable operation of the electric energy meter.

[0040] To solve the above-mentioned problem of serious heat generation of the TVS tube, the embodiment adds a control module to the output end of the blocking capacitor power supply rectifier module of each phase. Referring to Figure 3 , each phase control module includes a power supply switching unit 20 and a freewheeling switching unit 10, which are used to switch the power supply phase and shunt the current.

[0041] Specifically, referring to Figure 3The first end of each phase power supply switch unit 20 and the first end of each phase freewheeling switch unit 10 are respectively connected with the positive output end ZV of the corresponding phase rectifier module; the control end of each phase power supply switch unit 20 and the control end of each phase freewheeling switch unit 10 are respectively connected with the corresponding phase control pin CTL of the control chip; the second end of each phase power supply switch unit 20 is respectively communicated with the input end ZVT of the post-stage main power supply module; the second end of each phase freewheeling switch unit 10 is respectively connected with the negative output end ZD of the corresponding phase rectifier module; and the negative output end ZD of each phase rectifier module is connected with the input end ZDT of the post-stage main power supply module.

[0042] The power supply switch unit 20 can include a BJT (Bipolar Junction Transistor) tube and a PMOSFET tube. The freewheeling switch unit 10 can include an IGBT tube or a diode.

[0043] The control chip of the embodiment is used to supply voltage based on three-phase metering, and only one phase control pin outputs high level at the same time, at which time the phase power supply switch unit 20 is turned on and the freewheeling switch unit 10 is turned off, the post-stage main power supply module is powered by the phase RC power supply, the current flowing through the TVS tube is the difference between the RC power supply loop current and the post-stage load current, which is small and will not cause the TVS tube to heat up; at the same time, the other two phase control pins output low level, the corresponding phase power supply switch unit 20 is turned off, and the freewheeling switch unit 10 is turned on, the positive and negative output ends of the rectifier module form a low impedance loop through the freewheeling switch unit 10, and the current mainly flows through the freewheeling switch unit 10, avoiding flowing through the TVS tube, thereby ensuring that the TVS tube works at a suitable temperature and prolonging the service life of the three-phase meter.

[0044] In one possible implementation, as shown in FIG. 2, the power supply switch unit includes a first switch tube SA1, a second switch tube QA1, a first resistor RA4 and a second resistor RA3. Figure 1

[0045] The first end of the first resistor RA4 is connected with the corresponding phase control pin, the second end of the first resistor RA4 is connected with the base of the first switch tube SA1, the collector of the first switch tube SA1 is respectively connected with the first end of the second resistor RA3 and the gate of the second switch tube QA1, the second end of the second resistor RA3 and the source of the second switch tube QA1 are both connected with the first end of the power supply switch unit, the drain of the second switch tube QA1 is connected with the second end of the power supply switch unit, and the emitter of the first switch tube SA1 is grounded.

[0046] In the embodiment, the first switch tube SA1 can be a triode, and the second switch tube QA1 can be a PMOS tube. The control chip can be an MCU chip.​

[0047] Referring to Figure 1 and Figure 3 , the first end of the first resistor RA4 is connected with the corresponding phase control pin CTL_A, the second end of the first resistor RA4 is connected with the base of the first switch tube SA1, the collector of the first switch tube SA1 is connected with the first end of the second resistor RA3 and the gate of the second switch tube QA1 respectively, the second end of the second resistor RA3 and the source of the second switch tube QA1 are both connected with the first end of the power supply switch unit, the drain of the second switch tube QA1 is connected with the second end of the power supply switch unit, and the emitter of the first switch tube SA1 is grounded.

[0048] When the A phase control pin CTL_A of the control chip is high, the first switch tube SA1 is turned on, the G point of the second switch tube QA1 is pulled low, the second switch tube QA1 is turned on, the power supply switch unit is opened, the current flows to the rear main power supply module, and the power supply for the main loop load, and the electric energy meter works normally. When the control pin CTL_A is low, the first switch tube SA1 is cut off, the G point of the second switch tube QA1 is pulled high, the second switch tube QA1 is cut off, the power supply switch unit is closed, and the blocking capacitor power supply no longer supplies power to the main loop.

[0049] In one possible implementation, each phase control module further comprises a voltage dividing unit;

[0050] The voltage dividing unit comprises a first resistor unit and a second resistor unit;

[0051] The first end of the first resistor unit is connected with the positive output end of the corresponding phase rectification module, the second end of the second resistor unit is connected with the negative output end of the corresponding phase rectification module, and the second end of the first resistor unit and the first end of the second resistor unit are both connected with the first end of the first resistor.

[0052] In the embodiment, as shown in Figure 1 , the first resistor unit corresponding to the A phase comprises a resistor RA1, and the second resistor unit comprises a resistor RA2.

[0053] Specifically, at the moment of applying the mains, before the control chip is initialized, the pin CTL_A is in a high resistance state, the RA1 and the RA2 of the voltage dividing unit form a resistor voltage dividing unit, at this time, the voltage difference between ZV and ZVT is about 12V~15V, two resistors are configured to a suitable ratio to maintain the CTL_A at a high level, at this time, the power supply switch unit is opened, the freewheeling switch unit is closed, the main loop is powered, and the electric energy meter is started normally.

[0054] In one possible implementation, the power supply switch unit 20 further comprises a first diode DA1;

[0055] The anode of the first diode DA1 is connected with the drain of the second switch tube, and the cathode of the first diode DA1 is connected with the second end of the power supply switch unit.

[0056] Taking the A phase as an example, the anode of the first diode DA1 is connected with the drain of the second switch tube QA1, and the cathode is connected with the common positive electrode ZVT.

[0057] Since the three control modules are connected in parallel at the points ZVT and ZDT, when the A phase blocking capacitor power supply circuit is powered off, the diode DA1 blocks the current from the blocking capacitor power supply circuit of the other phase opened from this point to form a loop and affects the power supply of the main system.

[0058] In a possible implementation mode, referring to Figure 1 , the freewheeling switch unit 10 comprises a third switch tube SA3, a fourth switch tube SA2, a fifth switch tube QA3, a third resistor RA9, a fourth resistor RA8, a fifth resistor RA7 and a voltage dividing unit.

[0059] The first end of the third resistor RA9 is connected with the corresponding phase control pin, the second end of the third resistor RA9 is connected with the base of the third switch tube SA3, the collector of the third switch tube SA3 is connected with the first end of the fourth resistor RA8 and the first end of the fifth resistor RA7 respectively, the second end of the fourth resistor RA8 is connected with the power supply end, the second end of the fifth resistor RA7 is connected with the base of the fourth switch tube SA2, the collector of the fourth switch tube SA2 is connected with the first end of the voltage dividing unit, the second end of the voltage dividing unit is connected with the gate of the fifth switch tube QA3, the third end of the voltage dividing unit and the source of the fifth switch tube QA3 are connected with the first end of the freewheeling switch unit, and the emitter of the third switch tube SA3, the emitter of the fourth switch tube SA2 and the drain of the fifth switch tube QA3 are connected with the second end of the freewheeling switch unit.

[0060] In this embodiment, taking the A phase as an example, referring to Figure 1The first end of the third resistor RA9 is connected with the corresponding phase control pin CTL_A, the second end of the third resistor RA9 is connected with the base of the third switch tube SA3, the collector of the third switch tube SA3 is connected with the first end of the fourth resistor RA8 and the first end of the fifth resistor RA7 respectively, the second end of the fourth resistor RA8 is connected with the power supply end, the second end of the fifth resistor RA7 is connected with the base of the fourth switch tube SA2, the collector of the fourth switch tube SA2 is connected with the first end of the voltage dividing unit, the second end of the voltage dividing unit is connected with the gate of the fifth switch tube QA3, the third end of the voltage dividing unit and the source of the fifth switch tube QA3 are connected with the first end of the freewheeling switch unit; the emitter of the third switch tube SA3, the emitter of the fourth switch tube SA2 and the drain of the fifth switch tube QA3 are connected with the second end of the freewheeling switch unit.

[0061] In one possible implementation, as shown in Figure 1 The voltage dividing unit includes a sixth resistor RA6 and a seventh resistor RA5.

[0062] The first end of the sixth resistor RA6 is connected with the first end of the voltage dividing unit, the second end of the sixth resistor RA6 and the first end of the seventh resistor RA5 are connected with the second end of the voltage dividing unit; the second end of the seventh resistor RA5 is connected with the third end of the voltage dividing unit.

[0063] In the embodiment, the third switch tube SA3 and the fourth switch tube SA2 are both triodes, and the fifth switch tube QA3 is a PMOS tube.

[0064] In the embodiment, the A phase is taken as an example, and reference is made to Figure 1 When the A phase control pin CTL_A maintains a high level, the triode SA3 is turned on, the resistor RA7 is pulled low, the triode SA2 is cut off, the G point of the PMOS tube QA3 is at a high level, the PMOS tube QA3 is cut off, and the freewheeling switch unit is disconnected. At this time, the current flowing through the TVSA2 is equal to the current of the resistance-capacitance power supply circuit minus the current required by the main system load, and the current is small, which will not cause the TVSA2 to heat.

[0065] When the A-phase control pin CTL_A is low, SA3 is turned on, resistor RA7 is pulled low, transistor SA2 is turned off, and the lower end of RA6 is pulled to ground. The purpose of connecting RA5 and RA6 in series is to provide a suitable voltage level to the gate (G) point of PMOS transistor QA3. This ensures that the voltage is lower than the source (S) point of QA3, allowing QA3 to conduct; and that the voltage difference VSG between the two points does not exceed 8V (the withstand voltage between the gate and source points of the PMOS transistor), otherwise QA3 will be damaged. At this time, QA3 is turned on, and the freewheeling switch is open. This means that ZV and ZD at the back end of the rectifier module form a closed loop through QA3, creating a circuit for the RC power supply. Because QA3 has a very low impedance, all the current flows through QA3, and TVSA2 does not heat up. If the freewheeling switch is not open to form a closed loop, the current from the RC power supply circuit will flow through TVSA2, resulting in a very high power consumption in TVSA2, causing severe overheating and damage to the device.

[0066] See Figure 4 The document illustrates a flowchart of the control method for reducing the temperature of the TVS diode in a three-phase multi-resistance-capacitance power supply, provided by an embodiment of the present invention, and is applied to the control circuit described above; details are as follows:

[0067] S101: Obtain the three-phase metering voltage of the three-phase meter.

[0068] In this embodiment, the three-phase metering voltages connected to the three-phase meter, namely the A, B, and C phase grid voltages Ua, Ub, and Uc, are used to determine whether the voltage of each phase meets the power supply conditions.

[0069] Specifically, the control chip reads the voltages Ua, Ub, and Uc of the ABC phase metering chips according to a preset cycle. The preset cycle can be 1200ms.

[0070] S102: Based on the three-phase metering voltage of the three-phase meter, control one phase control pin to output a high-level signal and the other two phase control pins to output low-level signals.

[0071] The control chip selects one of the phases Ua, Ub, and Uc as the current power supply phase, outputs a high level to turn on the power supply switch unit and turn off the freewheeling switch unit of that phase; the control pins of the other two phases output a low level to turn off the power supply switch unit and turn on the freewheeling switch unit, forming a low-impedance shunt circuit.

[0072] The purpose of the above control methods is to ensure that the flow... Figure 2 The current in the TVS diodes at the front end of the DC-DC converter U1 and the TVS diodes at the front end of the rectifier modules in each RC power supply circuit is kept to a minimum, so that the heat generation is small, the temperature of the TVS diodes is kept within a reasonable range, the service life is improved, and the stable operation of the energy meter is maintained.

[0073] In one possible implementation, the specific implementation process of S102 includes:

[0074] S201: respectively judge whether the three-phase measurement voltages are greater than the initial starting voltage;

[0075] S202: determine the first phase and the other phases based on the number of phases whose measurement voltages are greater than the initial starting voltage; the other phases are the phases other than the first phase in the three phases; wherein, the first phase is only one;

[0076] S203: control the first phase control pin to output a high-level signal, and control the other phase control pins to output low-level signals.

[0077] In this embodiment, the resistance-capacitance power supply three-phase meter generally cooperates with a manganese copper sheet to perform measurement, one single-phase measurement chip is configured for each phase, and voltages, currents, powers, and electric quantities on the corresponding phases are measured. The electric energy meter has an initial starting voltage U0, that is, after the single-phase voltage U0 is applied, the electric energy meter can work normally, and the rated voltage of the electric energy meter is Un, generally U0 = 0.7Un.

[0078] After the three-phase measurement voltages of the current period are obtained, it is respectively judged whether the three-phase measurement voltages are greater than the initial starting voltage, and then according to the judgment result, the power supply phase, that is, the first phase, and the other two low-impedance shunt phases are determined.

[0079] In one possible implementation, the specific implementation process of S202 includes:

[0080] If one of the three-phase measurement voltages is greater than the initial starting voltage, the phase whose measurement voltage is greater than the initial starting voltage is set as the first phase;

[0081] If two of the three-phase measurement voltages are greater than the initial starting voltage, the two phases whose measurement voltages are greater than the initial starting voltage are alternately set as the first phase;

[0082] If all the three-phase measurement voltages are greater than the initial starting voltage, the three phases are alternately set as the first phase.

[0083] In this embodiment, if one of the three-phase measurement voltages is greater than the initial starting voltage, the chip outputs a high-level signal to the control pin of the corresponding phase control module, and turns on the power supply switch unit; the control pins of the corresponding phase control modules of the other two phases are all low-level, and the power supply switch units thereof are all turned off.

[0084] At this time, only one phase voltage supplies power to the post-stage main power supply module, for example, phase A, the current flowing through the TVS tube of the post-stage main power supply module is the difference between the main circuit current I and the load required current I0, that is, I-I0=0.3I, the resistance-capacitance power supply circuit current of the general electric energy meter under the single-phase rated voltage is about 50mA, 0.3I=15mA, the current is within the normal flow range of the TVS tube, and the TVS tube will not heat up. The power supply switch units of the resistance-capacitance power supply circuits of the other two phases are disconnected, and even if an external voltage is applied, the current will not flow through the main circuit, but will be introduced into the resistance-capacitance power supply circuit through QA3.

[0085] If two of the three measurement voltages are greater than the initial starting voltage, first, set the control pin of the phase corresponding to the condition not being true to low. Then set the control pins of the other two phases, one of which is high and one of which is low. After maintaining the first preset time length, set the control pin originally at low to high and the control pin originally at high to low. The first preset time length can be 600ms.

[0086] Specifically, the power supply switch unit of the phase line with a measurement voltage less than the initial starting voltage is turned off, and the power supply switch units of the other two phase lines with measurement voltages greater than the initial starting voltage are turned on alternately, on the one hand, the current flowing through the TVS tube in front of the DCDC converter U1 of the post-stage main power supply module is not too much, preventing the temperature from rising, on the other hand, the current flowing through the TVS tube in front of the rectifier bridge of the power supply of the two phase power lines is also reduced, reducing the heat generated.

[0087] If all of the three measurement voltages are greater than the initial starting voltage, set CTL_A to high, CTL_B and CTL_C to low, maintain the second preset time length, then set CTL_B to high, CTL_A and CTL_C to low, maintain the second preset time length, then set CTL_C to high, CTL_A and CTL_B to low, maintain the second preset time length, and repeat the above operation.

[0088] The second preset time length can be 400ms.

[0089] It should be understood that the size of the serial number of each step in the above embodiment does not mean the order of execution, the execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0090] The following is a device embodiment of the present application, and for details not described in detail, reference can be made to the corresponding method embodiments described above.

[0091] The embodiment of the present application provides a control device for reducing the temperature of a three-phase resistance-capacitance power supply TVS tube, only parts related to the embodiment of the present application are shown for the convenience of description, and the details are as follows:

[0092] The control device for reducing the temperature of the three-phase resistance-capacitance power supply TVS tube comprises:

[0093] A voltage acquisition module is configured to acquire three-phase metering voltages of a three-phase meter.

[0094] A level control module is configured to control one phase control pin to output a high-level signal and the other two phase control pins to output low-level signals according to the three-phase metering voltages of the three-phase meter.

[0095] In a possible implementation manner, the level control module comprises:

[0096] A voltage judgment unit is configured to judge whether the three-phase metering voltages are greater than an initial starting voltage respectively.

[0097] A first phase determination unit is configured to determine a first phase and other phases based on the number of phases whose metering voltages are greater than the initial starting voltage; the other phases are phases other than the first phase in the three phases; and the first phase is only one.

[0098] A level control unit is configured to control the first phase control pin to output a high-level signal and control the other phase control pins to output low-level signals.

[0099] In a possible implementation manner, the first phase determination unit comprises:

[0100] If there is a phase whose metering voltage is greater than the initial starting voltage in the three-phase metering voltages, the phase whose metering voltage is greater than the initial starting voltage is set as the first phase.

[0101] If there are two phases whose metering voltages are greater than the initial starting voltage in the three-phase metering voltages, the two phases whose metering voltages are greater than the initial starting voltage are alternately set as the first phase.

[0102] If all the three-phase metering voltages are greater than the initial starting voltage, the three phases are alternately set as the first phase.

[0103] In a possible implementation manner, the embodiment provides a resistance-capacitance power supply comprising the control circuit.

[0104] In a possible implementation manner, the embodiment provides a three-phase electric energy meter comprising the resistance-capacitance power supply.

[0105] Figure 5 is a schematic diagram of a terminal provided by the embodiment of the present application. Figure 5As shown, the terminal 5 of this embodiment includes a processor 50, a memory 51, and a computer program 52 stored in the memory 51 and executable on the processor 50. The processor 50 implements the steps in each of the above control method embodiments for reducing temperature of a three-phase voltage-dependent resistor-capacitor (TVS) tube when executing the computer program 52, such as Figure 4 The processor 50 implements the functions of each module / unit in each of the above apparatus embodiments when executing the computer program 52.

[0106] For example, the computer program 52 can be divided into one or more modules / units stored in the memory 51 and executed by the processor 50 to complete the present application. The one or more modules / units can be a series of computer program instruction segments capable of completing a specific function, which are used to describe the execution process of the computer program 52 in the terminal 5.

[0107] The terminal 5 can include, but is not limited to, the processor 50 and the memory 51. Those skilled in the art can understand that Figure 5 The terminal 5 is only an example and does not constitute a limitation on the terminal 5, which can include more or fewer components than those shown, or combine some components, or different components, for example, the terminal can also include an input / output device, a network access device, a bus, etc.

[0108] The processor 50 can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic components, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0109] The memory 51 can be an internal storage unit of the terminal 5, such as a hard disk or a memory of the terminal 5. The memory 51 can also be an external storage device of the terminal 5, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, and the like equipped on the terminal 5. Further, the memory 51 can also include both the internal storage unit and the external storage device of the terminal 5. The memory 51 is used to store the computer program and other programs and data required by the terminal. The memory 51 can also be used to temporarily store data that has been output or is to be output.

[0110] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above functional units and modules is exemplified, and in actual application, the above functions can be completed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit, and the integrated unit can be realized in the form of hardware or in the form of software functional unit. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction, and do not limit the protection scope of the present application. The specific working process of the units and modules in the above system can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0111] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described or recorded in detail in a certain embodiment can refer to the relevant description of other embodiments.

[0112] Those of ordinary skill in the art can appreciate that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0113] In the embodiments of the present application, it should be understood that the disclosed apparatus / terminal and method can be implemented in other manners. For example, the embodiments of the apparatus / terminal described above are merely schematic, and the division of the modules or units is merely logical function division, and there can be another division manner in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, devices or units, and can be electrical, mechanical or in other forms.

[0114] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place, or can be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiments.

[0115] In addition, each functional unit in the various embodiments of the present application can be integrated into a processing unit, or each unit can be a physically independent unit, or two or more units can be integrated into a unit. The integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0116] The integrated module / unit, if implemented in the form of a software functional unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on this understanding, all or part of the flow of the above-mentioned embodiment methods can be completed by a computer program instructing related hardware, and the computer program can be stored in a computer readable storage medium. When the processor executes the computer program, the steps of each of the above-mentioned control methods for reducing the temperature of the three-phase resistive-capacitive power supply TVS tube can be implemented. The computer program includes computer program code, which can be in the form of source code, object code, executable file or some intermediate form. The computer readable medium can include any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc.

[0117] The above-described embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A control circuit for reducing the temperature of a three-phase resistive-capacitive power supply (TVS) tube, characterized by, The blocking capacitor power supply comprises a rear-stage main power supply module, a three-phase rectifier module and a corresponding TVS tube of each phase; The control circuit comprises a control chip and a three-phase control module; each phase control module comprises a power supply switch unit and a freewheeling switch unit; The corresponding TVS tube of each phase is connected in parallel between the positive and negative input terminals of the corresponding phase rectifier module; the first end of the power supply switch unit of each phase and the first end of the freewheeling switch unit are connected with the positive output terminal of the corresponding phase rectifier module; the control end of the power supply switch unit of each phase and the control end of the freewheeling switch unit of each phase are connected with the corresponding phase control pin of the control chip; the second end of the power supply switch unit of each phase is in communication with the input terminal of the rear-stage main power supply module; the second end of the freewheeling switch unit of each phase is connected with the negative output terminal of the corresponding phase rectifier module; the impedance of the freewheeling switch unit is lower than that of the corresponding TVS tube; The control chip is used for controlling one phase control pin to output a high-level signal and the other two phase control pins to output low-level signals according to the three-phase metering voltage of the three-phase meter; The power supply switch unit of each phase is turned on when a high-level signal is input and is turned off when a low-level signal is input; the freewheeling switch unit of each phase is turned off when a high-level signal is input and is turned on when a low-level signal is input.

2. The control circuit for reducing temperature of a three-phase resistive-capacitive power supply TVS tube according to claim 1, characterized in that, The power supply switch unit comprises a first switch tube, a second switch tube, a first resistor and a second resistor; The first end of the first resistor is connected with the corresponding phase control pin, the second end of the first resistor is connected with the base of the first switch tube, the collector of the first switch tube is connected with the first end of the second resistor and the gate of the second switch tube, the second end of the second resistor and the source of the second switch tube are connected with the first end of the power supply switch unit, the drain of the second switch tube is connected with the second end of the power supply switch unit, and the emitter of the first switch tube is grounded.

3. The control circuit for reducing temperature of a three-phase resistive-capacitive power supply TVS tube according to claim 2, characterized in that, Each phase control module further comprises a voltage dividing unit; The voltage dividing unit comprises a first resistor unit and a second resistor unit; The first end of the first resistor unit is connected with the positive output terminal of the corresponding phase rectifier module, and the second end of the second resistor unit is connected with the negative output terminal of the corresponding phase rectifier module; the second end of the first resistor unit and the first end of the second resistor unit are connected with the first end of the first resistor.

4. The control circuit for reducing temperature of a three-phase resistive-capacitive power supply TVS tube according to claim 2, characterized in that, The power supply switch unit further comprises a first diode; The anode of the first diode is connected with the drain of the second switch tube, and the cathode of the first diode is connected with the second end of the power supply switch unit.

5. The control circuit for reducing temperature of a three-phase resistive-capacitive power supply TVS tube according to claim 1, characterized in that, The freewheeling switch unit comprises a third switch tube, a fourth switch tube, a fifth switch tube, a third resistor, a fourth resistor, a fifth resistor and a voltage dividing unit; The first end of the third resistor is connected with a corresponding phase control pin, the second end of the third resistor is connected with the base of the third switch tube, the collector of the third switch tube is connected with the first end of the fourth resistor and the first end of the fifth resistor respectively, the second end of the fourth resistor is connected with a power supply end, the second end of the fifth resistor is connected with the base of the fourth switch tube, the collector of the fourth switch tube is connected with the first end of the voltage division unit, the second end of the voltage division unit is connected with the gate of the fifth switch tube, the third end of the voltage division unit and the source of the fifth switch tube are both connected with the first end of the freewheeling switch unit; the emitter of the third switch tube, the emitter of the fourth switch tube and the drain of the fifth switch tube are all connected with the second end of the freewheeling switch unit.

6. The control circuit for reducing temperature of a three-phase resistive-capacitive power supply TVS tube according to claim 5, characterized in that, The voltage division unit comprises a sixth resistor and a seventh resistor; The first end of the sixth resistor is connected with the first end of the voltage division unit, the second end of the sixth resistor and the first end of the seventh resistor are both connected with the second end of the voltage division unit; the second end of the seventh resistor is connected with the third end of the voltage division unit.

7. A control method for reducing the temperature of a three-phase resistive-capacitive power supply (TVS) tube, characterized by, The control circuit is applied to any one of claims 1 to 6. The method comprises: Obtaining three-phase metering voltages of a three-phase meter; According to the three-phase metering voltages of the three-phase meter, controlling one phase control pin to output a high-level signal and the other two phase control pins to output low-level signals.

8. The control method of reducing temperature of a three-phase resistive-capacitive power supply TVS tube according to claim 7, characterized in that, The controlling one phase control pin to output a high-level signal and the other two phase control pins to output low-level signals according to the three-phase metering voltages of the three-phase meter comprises: Respectively judging whether the three-phase metering voltages are greater than an initial starting voltage; Based on the number of phases with metering voltages greater than the initial starting voltage, determining a first phase and other phases; the other phases are any phases in the three phases except the first phase; wherein, the first phase is only one; Controlling the first phase control pin to output a high-level signal and controlling the other phase control pins to output low-level signals.

9. The control method of reducing temperature of a three-phase resistive-capacitive power supply (TVS) tube according to claim 8, wherein, The determining a first phase and other phases based on the number of phases with metering voltages greater than the initial starting voltage; the other phases are any phases in the three phases except the first phase, comprises: If there is a phase with a metering voltage greater than the initial starting voltage in the three-phase metering voltages, the phase with a metering voltage greater than the initial starting voltage is set as the first phase; If there are two phases with metering voltages greater than the initial starting voltage in the three-phase metering voltages, the two phases with metering voltages greater than the initial starting voltage are alternately set as the first phase; If all the three-phase metering voltages are greater than the initial starting voltage, the three phases are alternately set as the first phase.

10. A blocking capacitor power supply characterized by comprising: The control circuit comprises any one of claims 1 to 6.

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