Power supply control system and control method based on far-end compensation

Abstract

The invention discloses a power supply control system and control method based on far-end compensation, and solves the problems that in the long-distance power supply process, when an existing compensation voltage monitoring circuit is used, a capacitor is in a short-circuit state at the moment when a capacitor X of a filter is charged, and at the moment, almost all output high voltage is loaded to an overcompensation sampling resistor; therefore, the problem that the resistor is burnt out due to overpower is solved. The overcompensation control system comprises a power conversion unit, a power control unit, a system filtering unit, an overcompensation sampling unit and a system control unit, compensation voltage is sampled through the overcompensation sampling resistor, compensation output is controlled through the overcompensation control circuit and the power control unit, the structure is simple, and the problem that the sampling compensation resistor is burnt due to overpower can be solved.

Description

Technical Field

[0001] The invention relates to a long-distance power supply overcompensation control method, and in particular to a power supply control system and a control method based on remote compensation. Background Art

[0002] More and more industries require long-distance DC output power supply. During the long-distance power supply process, due to the existence of line impedance, the final load-end voltage decays and fails to reach the expected voltage value, making remote voltage compensation a necessary function in this case.

[0003] In the process of voltage compensation for remote loads, in order to ensure that the compensation voltage is within the safe use range, it is necessary to detect the compensation voltage through an oversampling compensation resistor connected to the load. The commonly used circuit is as follows Figure 1 As shown, the filter X capacitor is charged by the output voltage, and the line impedance Rwire1 is relatively small. The filter X capacitor is in a short-circuit state at the moment of charging. At this time, the output high voltage is almost completely loaded on the over-compensation sampling resistor, causing the resistor to often be over-powered and burned. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that when there is loss in long-distance power supply, the existing compensation voltage monitoring circuit is in a short-circuit state when the filter X capacitor is charged, and the output high voltage is almost completely loaded on the over-compensation sampling resistor, causing the resistor to often be over-powered and burned, and to provide a power supply control system and control method based on remote compensation.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A power supply control system based on remote compensation, which is special in that it includes a power conversion unit, a power control unit, a system filter unit, an overcompensation sampling unit and a system control unit;

[0007] The system filter unit includes a common-mode inductor L1, a filter X capacitor CX2, and a timing control switch S1, wherein the input high end and the input low end of the common-mode inductor L1 are respectively connected to the positive electrode and the negative electrode of the output end of the power conversion unit, the output high end of the common-mode inductor L1 is connected to one end of the timing control switch S1, the other end of the timing control switch S1 is connected to the positive plate of the filter X capacitor CX2 and one end of the parallel load Rload, and the output low end negative electrode of the common-mode inductor L1 is connected to the negative plate of the filter X capacitor CX2 and the other end of the parallel load Rload;

[0008] The overcompensation sampling unit includes two overcompensation sampling resistors Rbc, two overcompensation control circuits and a timing control switch S2; one end of the two overcompensation sampling resistors Rbc is respectively connected to the positive electrode and the negative electrode of the output end of the power conversion unit; the other end of one of the overcompensation sampling resistors Rbc is connected to one end of the timing control switch S2, the other end of the timing control switch S2 is connected to one end of the parallel load Rload, and the other end of the other overcompensation sampling resistor Rbc is connected to the other end of the parallel load Rload; each of the overcompensation sampling resistors Rbc is connected in parallel with an overcompensation control circuit, which is used to regulate the output of the power conversion unit according to the voltage of the overcompensation sampling resistor Rbc; the two overcompensation control circuits are both connected to the power control unit;

[0009] The system control unit is connected to the timing control switch S1, the timing control switch S2 and the power control unit;

[0010] The power control unit is connected to the power conversion unit and is used to control the operation of the power conversion unit. The input end of the power conversion unit is used to connect to a three-phase AC power grid.

[0011] Furthermore, the power conversion unit includes an AC / DC rectifier circuit, a DC / DC conversion circuit and a module internal filter unit connected in sequence, the input end of the AC / DC rectifier circuit is connected to the three-phase AC power grid, the control ends of the AC / DC rectifier circuit and the DC / DC conversion circuit are connected to the power control unit, the input high end and the input low end of the module internal filter unit are respectively connected to one end of two overcompensation sampling resistors Rbc, and the output high end and the output low end of the module internal filter unit are respectively connected to the input high end and the input low end of the common mode inductor L1.

[0012] Furthermore, the internal filtering unit of the module includes a power filter common mode inductor L2, a filter resistor R2, a filter capacitor C2 and a filter X capacitor CX1, the input high end of the power filter common mode inductor L2 is connected to the positive electrode of the output end of the DC / DC conversion circuit and one end of one of the overcompensation sampling resistors Rbc, and the input low end of the power filter common mode inductor L2 is connected to the negative electrode of the output end of the DC / DC conversion circuit and one end of the other overcompensation sampling resistor Rbc; the output high end of the power filter common mode inductor L2 is connected to one end of the filter resistor R2, and the filter capacitor C2 and the filter X capacitor CX1 are connected in parallel between the other end of the filter resistor R2 and the output low end of the power filter common mode inductor L2, and the two plates of the filter X capacitor CX1 are respectively connected to the input high end and the input low end of the input end of the common mode inductor L1.

[0013] Furthermore, a control switch S3 is connected in parallel to the filter resistor R2, which is used to charge and protect the filter capacitor C2 and the filter X capacitor CX1 when the filter unit inside the module is started, thereby protecting the filter capacitor C2 and the filter X capacitor CX1.

[0014] Furthermore, each of the overcompensation control circuits includes a diode D1, a voltage-stabilizing diode D2, a protection resistor R1 and an optocoupler U1; the diode D1 is connected in parallel across the corresponding overcompensation sampling resistor Rbc, and the positive terminal of the diode D1 is connected to one end of the overcompensation sampling resistor Rbc connected to the timing control switch S2, the positive terminal of the voltage-stabilizing diode D2 is connected to one end of the protection resistor R1, the negative terminal of the voltage-stabilizing diode D2 is connected to the negative terminal of the diode D1, the other end of the protection resistor R1 is connected to the positive terminal of the diode D1, the input high end of the optocoupler U1 is connected to the positive terminal of the voltage-stabilizing diode D2, the input low end is connected to the other end of the protection resistor R1, the output high end of the optocoupler U1 is connected to the power control unit, and the output low end is grounded.

[0015] A power supply control method based on remote compensation uses a power supply control system based on remote compensation, which is special in that it includes the following steps:

[0016] Step 1: Connect the input end of the power conversion unit to the three-phase AC power grid, close the timing control switch S1 and open the timing control switch S2 through the system control unit, convert the AC power into DC power through the power conversion unit, and charge the filter X capacitor CX2 after passing through the common mode inductor L1;

[0017] Step 2, setting the charging time. After the charging time has passed, the system control unit closes the timing control switch S2, and the power conversion unit and the overcompensation sampling unit provide supplementary power to the parallel load Rload;

[0018] Step 3: Detect the voltage across the overcompensation sampling resistor Rbc through the overcompensation control circuit, and send the detected voltage to the power control unit; the power control unit adjusts the output voltage of the power conversion unit according to the detected voltage, and compensates the remote power supply voltage in real time.

[0019] Furthermore, step 3 is specifically as follows:

[0020] The voltage across the overcompensation sampling resistor Rbc is detected by the overcompensation control circuit, and the detected voltage is sent to the power control unit; the power control unit determines whether the detected voltage exceeds the preset voltage Vbc. If not, the power control unit increases the output voltage of the power conversion unit according to the detected voltage, so that the voltage across the overcompensation sampling resistor Rbc reaches the preset voltage Vbc, and remote power supply voltage compensation is performed on the parallel load Rload; if it exceeds, the output voltage of the power conversion unit is adjusted so as not to increase.

[0021] Furthermore, the charging time in step 2 is 5RC, where R represents the internal resistance of the filter X capacitor CX2, and C represents the capacity of the filter X capacitor CX2.

[0022] Beneficial effects of the present invention:

[0023] 1. The present invention is a power supply control system based on remote compensation, which samples the compensation voltage through an overcompensation sampling resistor, and controls the compensation output through an overcompensation control circuit and a power module-control unit. It has a simple structure and can solve the problem of over-power burning of the oversampling compensation resistor;

[0024] 2. The present invention provides a power supply control system and control method based on remote compensation. A timing control switch S1 is set in the system filter unit and a timing control switch S2 is set in the overcompensation sampling unit. The system control unit performs timing control on the two switches, thereby charging the filter X capacitor and effectively avoiding the problem of burning the overcompensation resistor by charging the filter X capacitor during the startup phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the voltage startup process of the existing compensation voltage monitoring circuit;

[0026] Figure 2 This is a module structure diagram of an embodiment of a power supply control system based on remote compensation of the present invention;

[0027] Figure 3 The figure is a schematic diagram of the circuit structure of an embodiment of a power supply control system based on remote compensation of the present invention.

[0028] In the figure, 1. power conversion unit, 1-1. AC / DC rectification circuit, 1-2. DC / DC conversion circuit, 1-3. module internal filtering unit; 2. power control unit; 3. system filtering unit; 4. overcompensation sampling unit; 5. system control unit. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] This embodiment is a power supply control system based on remote compensation, such as Figure 2 As shown, it includes a power conversion unit 1, a power control unit 2, a system filtering unit 3, an overcompensation sampling unit 4 and a system control unit 5;

[0031] like Figure 2 As shown, the power conversion unit 1 includes an AC / DC rectifier circuit 1-1, a DC / DC conversion circuit 1-2 and a module internal filter unit 1-3 connected in sequence, the input end of the AC / DC rectifier circuit 1-1 is connected to the three-phase AC power grid, the control ends of the AC / DC rectifier circuit 1-1 and the DC / DC conversion circuit 1-2 are connected to the power control unit 2, the input high end and the input low end of the module internal filter unit 1-3 are respectively connected to one end of two overcompensation sampling resistors Rbc, the output high end and the output low end of the module internal filter unit 1-3 are respectively connected to the input high end and the input low end of the common mode inductor L1, and the module internal filter unit 1-3 is used to perform internal filtering on the DC power output by the DC / DC conversion circuit 1-2.

[0032] like Figure 3 As shown, it is a partial circuit structure of a DC / DC conversion circuit 1-2 and a filter unit 1-3 inside the module, wherein the filter unit 1-3 inside the module includes a power filter common-mode inductor L2, a filter resistor R2, a filter capacitor C2 and a filter X capacitor CX1, the input high end of the power filter common-mode inductor L2 is connected to the positive electrode of the output end of the DC / DC conversion circuit 1-2 and one end of one of the overcompensation sampling resistors Rbc, and the input low end of the power filter common-mode inductor L2 is connected to the negative electrode of the output end of the DC / DC conversion circuit 1-2 and one end of the other overcompensation sampling resistor Rbc; the positive electrode of the output end of the power filter common-mode inductor L2 is connected to one end of the filter resistor R2, and the other end of the filter resistor R2 and the negative electrode of the output end of the power filter common-mode inductor L2 are respectively connected to the filter capacitor C2 and two plates of the filter X capacitor CX1, and the two plates of the filter X capacitor CX1 serve as the positive and negative electrodes of the output end of the power conversion unit 1, and are respectively connected to the input high end and input low end of the input end of the common-mode inductor L1.

[0033] The filter resistor R2 is connected in parallel with a control switch S3, which is used to control the charging of the filter capacitor C2 and the filter X capacitor CX1, thereby protecting the filter capacitor C2 and the filter X capacitor CX1.

[0034] The system filter unit 3 includes a common-mode inductor L1, a filter X capacitor CX2, and a timing control switch S1. The input high end and the input low end of the common-mode inductor L1 are respectively connected to the positive electrode and the negative electrode of the output end of the power conversion unit 1. The output high end of the common-mode inductor L1 is connected to one end of the timing control switch S1. The other end of the timing control switch S1 is connected to the positive plate of the filter X capacitor CX2 and one end of the parallel load Rload. The output low end negative electrode of the common-mode inductor L1 is connected to the negative plate of the filter X capacitor CX2 and the other end of the parallel load Rload.

[0035] The overcompensation sampling unit 4 includes two overcompensation sampling resistors Rbc, two overcompensation control circuits and a timing control switch S2; one end of the two overcompensation sampling resistors Rbc is respectively connected to the positive electrode and the negative electrode of the output end of the power conversion unit 1; the other end of one of the overcompensation sampling resistors Rbc is connected to one end of the timing control switch S2, the other end of the timing control switch S2 is connected to one end of the parallel load Rload, and the other end of the other overcompensation sampling resistor Rbc is connected to the other end of the parallel load Rload; each overcompensation sampling resistor Rbc is connected in parallel with an overcompensation control circuit, which is used to adjust the output of the power conversion unit 1 according to the voltage of the overcompensation sampling resistor Rbc; the two overcompensation control circuits are both connected to the power control unit 2;

[0036] Each over-compensation control circuit includes a diode D1, a voltage-stabilizing diode D2, a protection resistor R1 and an optocoupler U1; the diode D1 is connected in parallel across the corresponding over-compensation sampling resistor Rbc, and the positive terminal of the diode D1 is connected to one end of the over-compensation sampling resistor Rbc connected to the timing control switch S2, the positive terminal of the voltage-stabilizing diode D2 is connected to one end of the protection resistor R1, the negative terminal of the voltage-stabilizing diode D2 is connected to the negative terminal of the diode D1, the other end of the protection resistor R1 is connected to the positive terminal of the diode D1, the input high end of the optocoupler U1 is connected to the positive terminal of the voltage-stabilizing diode D2, the input low end is connected to the other end of the protection resistor R1, the output high end of the optocoupler U1 is connected to the power control unit 2, and the output low end is grounded.

[0037] The system control unit 5 is connected to the timing control switch S1, the timing control switch S2 and the power control unit 2;

[0038] The power control unit 2 is connected to the power conversion unit 1 and is used to control the operation of the power conversion unit 1. The input end of the power conversion unit 1 is used to connect to a three-phase AC power grid.

[0039] The present embodiment is a power supply control system based on remote compensation. In an application where remote voltage compensation and output power filtering are required at the same time after the power conversion unit 1 outputs direct current, the problem of burnout of the over-compensated sampling resistor is solved by effectively controlling the switching timing of the remote compensation sampling signal and the output power switch.

[0040] The power conversion unit 1 may adopt a mode of connecting multiple power conversion units 1 in parallel, wherein the master power conversion unit 1 receives a remote voltage compensation signal, and other slave power conversion units 1 follow the master power conversion unit 1 to perform current sharing control.

[0041] This embodiment is a power supply control system based on remote compensation. In some uses, due to the long output cable and the existence of a certain impedance of the cable, the output voltage of the module, after passing through the output cable, at the remote parallel load, the voltage does not reach the preset voltage value. Remote compensation can ensure that the output voltage of the remote parallel load is always the output set voltage Vload. The remote compensation system determines the voltage Vbc across the overcompensation sampling resistor according to the cable loss voltage, and promptly increases the output voltage Vmk of the power conversion unit 1 to compensate for the voltage loss on the cable.

[0042] The over-compensation protection principle of the control system in this embodiment is as follows: the system is pre-set to reach the compensation cable voltage VBC, VBC = Vmk-Vload, and an over-compensation sampling resistor Rbc is connected in series in the compensation sampling loop. When the compensation cable voltage VBC is reached, the voltage of the over-compensation sampling resistor Rbc is Vbc, and the system will detect the voltage across Rbc. When it is found that the voltage exceeds the compensation voltage Vbc, the Zener diode D2 is turned on, the optocoupler U1 is turned on, and the over-compensation signal on the transistor side of the optocoupler U1 changes from high to low, and this signal is sent to the power control unit 2 for processing. Under normal circumstances (no over-compensation occurs), the over-compensation signal is high level. When the over-compensation signal is low level, the power control unit 2 no longer controls the output of the output voltage Vmk of the power conversion unit 1 to increase the output, thereby achieving the purpose of over-compensation.

[0043] A power supply control method based on remote compensation comprises the following steps:

[0044] Step 1: Connect the input end of the power conversion unit 1 to the three-phase AC power grid, close the timing control switch S1 and open the timing control switch S2 through the system control unit 5, convert the AC power into DC power through the power conversion unit 1, and charge the filter X capacitor CX2 after passing through the common mode inductor L1;

[0045] Step 2, setting the charging time. After the charging time has passed, the system control unit 5 closes the timing control switch S2, and the power conversion unit 1 and the overcompensation sampling unit 4 provide supplementary power to the parallel load Rload;

[0046] Step 3, detect the voltage across the overcompensation sampling resistor Rbc through the overcompensation control circuit, and send the detected voltage to the power control unit 2; the power control unit 2 determines whether the detected voltage exceeds the preset voltage Vbc. If not, the power control unit 2 increases the output voltage of the power conversion unit 1 according to the detected voltage, and performs remote power supply voltage compensation for the parallel load Rload; if exceeded, the output voltage of the power conversion unit 1 is adjusted to no longer increase.

[0047] The invention controls the closing timing of the remote compensation signal and the power output switch, and connects the timing control switch S2 in series on the signal line of the remote compensation voltage sampling. After the circuit is started, before the timing control switch S1 is closed, the timing control switch S2 is in the open state. After the timing control switch S1 is closed, the main power circuit charges the filter X capacitor CX2. After the charging of the filter X capacitor CX2 is completed, the timing control switch S2 is closed again. In this way, the circuit that charges the filter X capacitor CX2 through the remote compensation voltage sampling signal line during the startup process is avoided. Similarly, at the disconnection timing, the timing control switch S2 is disconnected first, and then the timing control switch S1 is disconnected. According to this logic control scheme, the problem of burning the over-compensation sampling resistor during the startup and shutdown process of the previous scheme is effectively solved, providing a safe and reliable technical solution for such applications.

[0048] In this embodiment, the charging time in step 2 is 5RC, which can ensure that the filter X capacitor is fully charged, and is verified by experiments:

[0049] The time for closing the timing control switch S2 needs to be determined according to the charging time of the filter X capacitor CX1. The time required for the charging time of the filter X capacitor CX1 is expressed as: Vt = Vmk*[1–exp(-t / RC)]; Vmk is the output voltage of the power conversion unit 1;

[0050] From the above formula, we can see that because the exponential value can only be infinitely close to 0 but will never be equal to 0, it takes infinite time to fully charge the capacitor.

[0051] When t = RC, Vt = 0.63Vmk;

[0052] When t = 2RC, Vt = 0.86Vmk;

[0053] When t = 3RC, Vt = 0.95Vmk;

[0054] When t = 4RC, Vt = 0.98Vmk;

[0055] When t = 5RC, Vt = 0.99Vmk;

[0056] It can be seen from the above that after 3 to 5 RCs, the charging process is basically completed. In order to reliably ensure that the capacitor is fully charged, the time length for the capacitor to be fully charged is set to t=5RC in the present invention.

[0057] The input end of the power conversion unit 1 in this embodiment is connected to 380V / 50Hz AC power, and a 270Vdc voltage is output after AC-DC conversion. After filtering by the internal filter units 1-3 of the module, it is input into the system filter unit 3 for filtering again and then input into the parallel load (Vload=270Vdc). Because the parallel load cable is long, the impedance on the cable (2*Rwire: there are 2 parallel load cables) causes voltage loss VBC, resulting in the voltage at the parallel load end not reaching 270Vdc. In order to keep the voltage at the parallel load end at 270Vdc, it is necessary to determine the over-compensation sampling resistor voltage Vbc according to the cable loss, and adjust the power module output voltage Vmk in real time so that Vmk=VBC+270Vdc.

[0058] At the same time, VBC=Ilaod*2*Rwire, (Iload: parallel load current)

[0059] Vmk=Ilaod*2*Rwire+270Vdc

[0060] The parallel load current Iload changes in real time, so Vmk is also changed and adjusted in real time.

[0061] This implementation case needs to achieve two effects.

[0062] Effect 1: The output voltage Vmk is adjusted in real time according to the real-time change of the parallel load current Iload. Vmk=Ilaod*2*Rwire+270Vdc.

[0063] Effect 2: Limit the overcompensation of a single-side cable to 5Vdc, and the total compensation voltage is 10Vdc (VBC). When the compensation voltage of any cable exceeds 5Vdc, overcompensation will no longer be performed.

[0064] Implementation instructions for effect 2: When the cable is long enough, Rwire will continue to increase. Or the parallel load current Ilaod continues to increase under certain conditions. According to Vmk=Ilaod*2*Rwire+270Vdc, the output voltage Vmk of the power conversion unit 1 will continue to increase. Vmk cannot be adjusted indefinitely. Adjusting it too high will cause damage to components in the circuit. In order to protect the circuit structure, the overcompensation of the single-sided cable is limited to 5Vdc. When the compensation voltage exceeds 5Vdc, overcompensation will no longer be performed, and the output is 2 cables, that is, the range of Vmk is: 270Vdc~280Vdc;

[0065] When the cable voltage drop is between 0 and 5 Vdc, the module's output voltage Vmk is dynamically adjusted so that the output end can be maintained at 270 Vdc.

[0066] When the cable voltage drop is greater than 5Vdc, the output voltage Vmk of the module is maintained at a maximum of 280Vdc. At this time, the 270Vdc at the parallel load end is no longer guaranteed, which protects the circuit.

[0067] like Figure 3 As shown, when the three-phase AC power is sent to the power conversion unit 1, it passes through the power control unit 2 (such as Figure 2 ) sends a startup command to the power conversion unit 1, and the power conversion unit 1 outputs a Vmk DC voltage. When the system detects that the output Vmk is established, the system control unit 5 sends a closing command to the timing control switch S1, and the filter X capacitor CX2 starts to charge the capacitor. After the charging lasts for t=5RC time, the system control unit 5 sends a closing command to the timing control switch S2. At this time, the remote compensation mechanism is started, and according to the voltage Vload sampled by the remote output and the output voltage Vmk of the power conversion unit 1, combined with the power control unit 2, dynamic compensation is performed to adjust the value of Vmk so that Vload=270Vdc. The purpose of dynamic compensation is achieved.

[0068] Through the remote compensation sampling circuit, when the system detects that the system is over-compensated at a certain moment, a low-level signal is sent to the power module control unit through the over-compensation circuit of the power module to adjust the control output Vmk to maintain at a maximum of 280Vdc, thereby achieving the purpose of over-compensation protection.

[0069] The power supply control system based on remote compensation in this embodiment has been applied in batches in products to achieve real-time dynamic compensation and real-time over-compensation protection functions. The use effect is good and the performance is stable and reliable.

[0070] The above description is only a specific embodiment of the present invention, and a comparison of the effects of the specific embodiments and the related comparative examples, but the protection scope of the present invention is not limited thereto, and any changes or substitutions within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A power supply control system based on remote compensation, characterized in that: It comprises a power conversion unit (1), a power control unit (2), a system filtering unit (3), an overcompensation sampling unit (4) and a system control unit (5); The system filter unit (3) comprises a common-mode inductor L1, a filter X capacitor CX2 and a timing control switch S1, wherein the input high end and the input low end of the common-mode inductor L1 are respectively connected to the positive electrode and the negative electrode of the output end of the power conversion unit (1), the output high end of the common-mode inductor L1 is connected to one end of the timing control switch S1, the other end of the timing control switch S1 is connected to the positive plate of the filter X capacitor CX2 and one end of the parallel load Rload, and the output low end negative electrode of the common-mode inductor L1 is connected to the negative plate of the filter X capacitor CX2 and the other end of the parallel load Rload; The overcompensation sampling unit (4) comprises two overcompensation sampling resistors Rbc, two overcompensation control circuits and a timing control switch S2; one end of the two overcompensation sampling resistors Rbc is respectively connected to the positive electrode and the negative electrode of the output end of the power conversion unit (1); the other end of one of the overcompensation sampling resistors Rbc is connected to one end of the timing control switch S2, the other end of the timing control switch S2 is connected to one end of the parallel load Rload, and the other end of the other overcompensation sampling resistor Rbc is connected to the other end of the parallel load Rload; each of the overcompensation sampling resistors Rbc is connected in parallel with an overcompensation control circuit, and is used to regulate the output of the power conversion unit (1) according to the voltage of the overcompensation sampling resistor Rbc; the two overcompensation control circuits are both connected to the power control unit (2); The system control unit (5) is connected to the timing control switch S1, the timing control switch S2 and the power control unit (2); The power control unit (2) is connected to the power conversion unit (1) and is used to control the operation of the power conversion unit (1); the input end of the power conversion unit (1) is used to connect to a three-phase AC power grid.

2. According to claim 1, a power supply control system based on remote compensation is used, characterized in that: the power conversion unit (1) includes an AC / DC rectifier circuit (1-1), a DC / DC conversion circuit (1-2) and a module internal filter unit (1-3) connected in sequence, the input end of the AC / DC rectifier circuit (1-1) is connected to a three-phase AC power grid, the control ends of the AC / DC rectifier circuit (1-1) and the DC / DC conversion circuit (1-2) are both connected to a power control unit (2), the input high end and the input low end of the module internal filter unit (1-3) are respectively connected to one end of two over-compensation sampling resistors Rbc, and the output high end and the output low end of the module internal filter unit (1-3) are respectively connected to the input high end and the input low end of the common mode inductor L1.

3. A power supply control system based on remote compensation according to claim 2, characterized in that: the internal filtering unit (1-3) of the module includes a power filtering common mode inductor L2, a filtering resistor R2, a filtering capacitor C2 and a filter X capacitor CX1, the input high end of the power filtering common mode inductor L2 is connected to the positive electrode of the output end of the DC / DC conversion circuit (1-2) and one end of one of the overcompensation sampling resistors Rbc, and the input low end of the power filtering common mode inductor L2 is connected to the negative electrode of the output end of the DC / DC conversion circuit (1-2) and one end of the other overcompensation sampling resistor Rbc; the output high end of the power filtering common mode inductor L2 is connected to one end of the filtering resistor R2, and the filtering capacitor C2 and the filter X capacitor CX1 are connected in parallel between the other end of the filtering resistor R2 and the output low end of the power filtering common mode inductor L2, and the two plates of the filter X capacitor CX1 are respectively connected to the input high end and the input low end of the input end of the common mode inductor L1.

4. The power supply control system based on remote compensation according to claim 1, characterized in that: The filter resistor R2 is connected in parallel with a control switch S3, which is used to charge and protect the filter capacitor C2 and the filter X capacitor CX1 when the filter unit (1-3) inside the module is started.

5. The power supply control system based on remote compensation according to claim 1, characterized in that: Each of the overcompensation control circuits comprises a diode D1, a voltage-stabilizing diode D2, a protection resistor R1 and an optocoupler U1; the diode D1 is connected in parallel to the two ends of the corresponding overcompensation sampling resistor Rbc, and the positive terminal of the diode D1 is connected to one end of the overcompensation sampling resistor Rbc connected to the timing control switch S2, the positive terminal of the voltage-stabilizing diode D2 is connected to one end of the protection resistor R1, the negative terminal of the voltage-stabilizing diode D2 is connected to the negative terminal of the diode D1, the other end of the protection resistor R1 is connected to the positive terminal of the diode D1, the input high end of the optocoupler U1 is connected to the positive terminal of the voltage-stabilizing diode D2, the input low end is connected to the other end of the protection resistor R1, the output high end of the optocoupler U1 is connected to the power control unit (2), and the output low end is grounded.

6. A power supply control method based on remote compensation, using the power supply control system based on remote compensation according to claim 1, characterized in that: The following steps are involved: Step 1: Connect the input end of the power conversion unit (1) to a three-phase AC power grid, close the timing control switch S1 and open the timing control switch S2 through the system control unit (5), convert the AC power into DC power through the power conversion unit (1), and charge the filter X capacitor CX2 after passing through the common mode inductor L1; Step 2, setting the charging time. After the charging time has elapsed, the system control unit (5) closes the timing control switch S2, and the power conversion unit (1) and the overcompensation sampling unit (4) provide supplementary power to the parallel load Rload; Step 3: The voltage across the overcompensation sampling resistor Rbc is detected by the overcompensation control circuit, and the detected voltage is sent to the power control unit (2); the power control unit (2) adjusts the output voltage of the power conversion unit (1) according to the detected voltage, and performs real-time compensation for the remote power supply voltage.

7. The power supply control method based on remote compensation according to claim 6, characterized in that: Step 3 is as follows: The voltage across the overcompensation sampling resistor Rbc is detected by an overcompensation control circuit, and the detected voltage is sent to a power control unit (2); the power control unit (2) determines whether the detected voltage exceeds a preset voltage Vbc; if not, the power control unit (2) adjusts the output voltage of the power conversion unit (1) to increase according to the detected voltage, and performs remote power supply voltage compensation on the parallel load Rload; if exceeded, the output voltage of the power conversion unit (1) is adjusted to no longer increase.

8. The power supply control method based on remote compensation according to claim 6, characterized in that: The charging time in step 2 is 5RC, where R represents the internal resistance of the filter X capacitor CX2, and C represents the capacity of the filter X capacitor CX2.

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