Long cable power supply voltage drop measurement and stabilized power supply system and method

Abstract

The embodiment of the specification provides a long cable power supply voltage drop measurement and voltage stabilization function integrated power supply system and method, wherein the system comprises an AC-DC converter, a DC-AC converter and a digital controller, the AC-DC converter works in a voltage stabilization mode, provides a stable direct current voltage for the DC-AC conversion and completes power factor correction; the DC-AC converter works in a voltage drop measurement mode or a voltage stabilization mode under the control of the digital controller, is used for acquiring long cable rear end and front end voltages and calculating a voltage drop when working in the voltage drop measurement mode, and outputs a stable alternating current voltage to a load when working in the voltage stabilization mode; and the digital controller controls the DC-AC to automatically switch between the voltage stabilization mode and the voltage drop measurement mode. The long distance power supply voltage drop and fluctuation can be automatically compensated, output voltage stabilization is realized, the measurement and voltage stabilization functions of single-phase and three-phase lines are compatible, and the system has an important role in line load monitoring and safety evaluation and stable power supply when the line diameter is insufficient.

Description

Technical Field

[0001] This document relates to the field of electronic power technology, and in particular to an integrated power supply system and method for measuring and stabilizing voltage drop in long cable power supply. Background Technology

[0002] In fields such as natural disaster relief and military operations, emergency communication power supply plays a crucial role. However, when constructing emergency power supply systems for these scenarios, cable diameter margins are often insufficient, current-carrying capacity is limited, or the connected power grid lacks rigidity. This results in large voltage fluctuations under different time periods and load conditions, easily causing unstable power supply or shutdowns of communication equipment connected to long cables. Therefore, measuring voltage drop and implementing back-end voltage stabilization for cables of different lengths or diameters under varying load conditions is of great significance for assessing the load's safe operating capability and maintaining minimum stable power supply capacity.

[0003] Currently, most voltage drop testers with automatic measurement and display functions are used to measure DC voltage drop, and their allowable voltage drop range is limited. While using an equal-power resistance box to connect and measure AC cable voltage drop can realistically simulate the actual load situation, it requires constant load adjustment and measurement recording, resulting in a large workload and insufficient automation. Furthermore, the load power loss is high, leading to energy waste, and the large size and weight of high-power resistance boxes make them unsuitable for portability.

[0004] Using transformer winding step-up / step-down compensation to compensate for cable voltage drop for voltage stabilization is a common method in most existing products. It has the advantages of low cost and strong resistance to load surges, but it has disadvantages such as large coil size and weight, and inability to accurately stabilize the output voltage. Currently, AC voltage stabilization power supplies using battery-less UPS or power electronic conversion methods typically cannot support single / three-phase input / output on a single device and lack voltage drop measurement functionality. Summary of the Invention

[0005] This invention provides an integrated power supply system and method for measuring and stabilizing voltage drop in long cable power supply, which is compatible with single-phase or three-phase input / output modes. The system can switch working modes according to the settings to realize voltage drop measurement and voltage stabilization functions.

[0006] This invention provides an integrated power supply system for measuring and regulating voltage drop over long power cables, comprising: an AC-DC converter, a DC-AC converter, and a digital controller.

[0007] The AC-DC converter operates in regulated mode, providing a stable DC voltage for DC-AC conversion and performing power factor correction.

[0008] The DC-AC converter operates in either voltage drop measurement mode or voltage regulation mode under the control of a digital controller. In voltage drop measurement mode, it is used to obtain the voltage at the front and rear ends of a long cable and calculate the voltage drop. In voltage regulation mode, it outputs a stable AC voltage to the load.

[0009] The digital controller automatically switches between voltage regulation mode and voltage drop measurement mode for DC-AC.

[0010] This invention provides a power supply method integrating voltage drop measurement and voltage stabilization functions for long cable power supplies, comprising:

[0011] When the integrated power supply system for long cable power supply voltage drop measurement and voltage regulation is operating in voltage regulation mode, the AC-DC converter provides a stable DC voltage for DC-AC conversion and completes power factor correction; the DC-AC converter independently outputs a stable AC voltage to the load.

[0012] When the DC-AC converter operates in voltage drop measurement mode under the control of a digital controller, it is used to acquire the voltage at the front and rear ends of a long cable and calculate the voltage drop.

[0013] The power-time list is set in voltage drop measurement mode by displaying the control device, and the duration test of different power conditions is automatically performed according to the power-time list, generating reports and displaying them.

[0014] This invention integrates cable voltage drop measurement and voltage regulation compensation functions into a single hardware system. Voltage drop measurement is achieved using a power loop, making it a non-power-consuming voltage drop testing system. It can measure cable voltage drop with minimal power consumption. Furthermore, since the measuring device is a pure converter system, it has the advantages of small size and light weight. It is compatible with both single-phase and three-phase cable voltage drop measurement and voltage regulation functions, eliminating the need for multiple systems to meet different power supply conditions. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in one or more embodiments of this specification or in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a circuit configuration diagram for the cable voltage drop measurement mode according to an embodiment of the present invention;

[0017] Figure 2 This is an internal circuit diagram of the voltage drop measurement mode in an embodiment of the present invention;

[0018] Figure 3 This is a schematic diagram of the system wiring configuration in the voltage regulation output mode according to an embodiment of the present invention;

[0019] Figure 4 This is an internal circuit diagram of the regulated output mode according to an embodiment of the present invention;

[0020] Figure 5 This is a schematic diagram of the internal circuit of the single-phase cable measurement / voltage stabilization function in an embodiment of the present invention;

[0021] Figure 6 This is a schematic diagram of the internal circuit of the three-phase cable measurement / voltage regulation function in an embodiment of the present invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this document.

[0023] System Implementation Examples

[0024] According to an embodiment of the present invention, an integrated power supply system for measuring and regulating voltage drop in long cable power supply is provided, comprising:

[0025] AC-DC converter, DC-AC converter, and digital controller.

[0026] The AC-DC converter operates in voltage regulation mode, providing a stable DC voltage for the DC-AC conversion and performing power factor correction.

[0027] The DC-AC converter operates in either voltage drop measurement mode or voltage regulation mode under the control of a digital controller. In voltage drop measurement mode, it is used to obtain the voltage at the front and rear ends of the long cable and calculate the voltage drop. In voltage regulation mode, it outputs a stable AC voltage to the load.

[0028] A digital controller controls the DC-AC to automatically switch between the voltage regulation mode and the voltage drop measurement mode.

[0029] AC-DC converters include: a three-phase T-type three-level PWM rectifier with a midpoint or a Vienna rectifier.

[0030] The DC-AC converter includes a three-phase four-arm inverter, which outputs three phases A, B, and C and an external neutral line at the midpoint of each arm.

[0031] The integrated power supply system for long cable power supply voltage drop measurement and voltage regulation further includes: a display and control device connected to a digital controller, used to set a power-time list in voltage drop measurement mode, and automatically perform duration tests for different power conditions according to the power-time list, generate reports and display them; and to display the system status and adjust the output voltage in voltage regulation mode.

[0032] When the DC-AC operates in measurement mode, the output terminal of the DC-AC is connected to the front end of the long cable through the power feeder to form a power loop, thereby generating a voltage drop on the cable corresponding to the set power, and thus obtaining the voltage drop generated by the long cable.

[0033] When the DC-AC is operating in voltage regulation mode, the DC-AC output is directly connected to the load.

[0034] The digital controller is further used to control the connection method of the output terminal of the DC-AC converter to be compatible with single-phase or three-phase power grids.

[0035] When measuring cable voltage drop under a three-phase power grid, the three-phase cable output by the DC-AC converter is connected to the corresponding positions A, B, and C of the three-phase power grid at the front end of the long cable.

[0036] When the DC-AC converter measures the cable voltage drop under a single-phase power grid, one of the three phases of the DC-AC output is connected to the corresponding position at the front end of the long cable, and a neutral wire is led out from the front end of the long cable connected to the N phase to the system.

[0037] The following is combined with Figures 1 to 4 This section provides a detailed explanation of the specific operating modes of the integrated power supply system for long cable power supply voltage drop measurement and voltage regulation, specifically in voltage drop measurement mode and voltage regulation mode.

[0038] Figure 1 This is a circuit configuration diagram for the cable voltage drop measurement mode in an embodiment of the present invention. In order to measure the voltage drop when a large current flows through a long cable, the inverter output is fed back to the front end of the long cable via a shorter power feeder. The power supply device controls the feeder current to form a power loop, thereby generating a voltage drop on the cable corresponding to the set power. The power supply device reads the output and input voltages and takes the difference to obtain the cable voltage drop, generating a corresponding report curve.

[0039] Figure 2 This is an internal circuit diagram of the voltage drop measurement mode according to an embodiment of the present invention. Figure 2As can be seen from the power feeder connection method, in three-phase measurement mode, a, b, and c are fed back to the corresponding positions A, B, and C at the cable end connected to the three-phase power grid, respectively. The phase voltage at the input and output positions is calculated based on the line voltage. In single-phase cable voltage drop measurement, only one phase from a, b, and c needs to be connected to the cable end. At the same time, a neutral wire measurement line is led out from the end of the long cable connected to phase N to the device to enable accurate measurement of single-phase line voltage drop.

[0040] During voltage drop measurement, the user can manually set the power supply, and the cable voltage drop value is measured and displayed in real time; alternatively, automatic voltage drop testing can be performed according to preset power and duration, and corresponding reports are generated. The power loop feeder method effectively measures the cable voltage drop when the actual load current is large, while avoiding excessive power loss as in traditional resistance methods.

[0041] Figure 3 This is a schematic diagram of the system wiring configuration in the voltage regulation output mode of this invention. In order to compensate for the voltage drop caused by the long cable, the power supply device is used for voltage regulation, and the output terminal of the power supply device is directly connected to the load.

[0042] Figure 4 This is an internal circuit diagram of the regulated output mode according to an embodiment of the present invention. Figure 4 In this circuit, the circuit structure can be configured as needed, and the control strategy can be switched accordingly by DSP digital control, thereby supporting single-phase input / output and three-phase input / output modes. The configuration circuit for single-phase input / output is as follows: Figure 5 As shown, the three-phase input / output configuration circuit is as follows: Figure 6 As shown, S1 and S2 are two relay switches, and different circuit configurations are achieved by software by blocking the corresponding power devices and relays. In both voltage drop measurement and voltage regulation modes, the AC-DC converter always operates in voltage regulation mode, thus providing a stable DC voltage (udc) to the DC-AC converter and performing power factor correction. In the cable voltage drop measurement function, the DC-AC converter controls and stabilizes the output current according to the set value, and in the voltage regulation function, it stabilizes the output voltage.

[0043] Figure 5 This is a schematic diagram of the internal circuit of the single-phase cable measurement / voltage stabilization function according to an embodiment of the present invention. Figure 6 This is a schematic diagram of the internal circuit of the three-phase cable measurement / voltage regulation function according to an embodiment of the present invention. Figure 6 In the case of three-phase four-wire output, the neutral line n is drawn from the midpoint of the fourth bridge arm, S2 is disconnected, and the inverter output can withstand a large unbalance component.

[0044] The following beneficial effects are achieved by employing the embodiments of the present invention:

[0045] 1. Multifunctional. It integrates cable voltage drop measurement and voltage stabilization compensation functions into a single hardware system.

[0046] 2. Small and lightweight. It uses a power loop to measure voltage drop, making it a non-power-consuming voltage drop testing system. It can measure cable voltage drop with minimal power consumption. At the same time, since the measuring device is a pure converter system, it has the advantages of small size and light weight.

[0047] 3. Strong compatibility. It is compatible with both single-phase and three-phase cable voltage drop measurement and voltage stabilization functions, eliminating the need for multiple different systems to meet different power supply conditions.

[0048] Method Implementation Examples

[0049] This invention provides a power supply method integrating voltage drop measurement and voltage stabilization for long cable power supplies, comprising:

[0050] When the integrated power supply system for long cable power supply voltage drop measurement and voltage regulation is operating in voltage regulation mode, the AC-DC converter provides a stable DC voltage for DC-AC conversion and completes power factor correction; the DC-AC converter independently outputs a stable AC voltage to the load.

[0051] When the DC-AC converter operates in voltage drop measurement mode under the control of a digital controller, it is used to acquire the voltage at the front and rear ends of a long cable and calculate the voltage drop.

[0052] The power-time list is set in voltage drop measurement mode by displaying the control device, and the duration test of different power conditions is automatically performed according to the power-time list, generating reports and displaying them.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A power supply system integrating voltage drop measurement and voltage stabilization functions for long cable power supply, characterized in that, include: AC-DC converter, DC-AC converter, and digital controller. The AC-DC converter operates in voltage regulation mode, providing a stable DC voltage for the DC-AC converter and performing power factor correction. The DC-AC converter operates in either voltage drop measurement mode or voltage regulation mode under the control of the digital controller. In voltage drop measurement mode, it is used to obtain the voltage at the front end and rear end of the long cable and calculate the voltage drop. In voltage regulation mode, it outputs a stable AC voltage to the load. A digital controller controls the DC-AC converter to automatically switch between the voltage regulation mode and the voltage drop measurement mode; When the DC-AC converter operates in measurement mode, the output terminal of the DC-AC converter is fed back to the front end of the long cable on the input side of the AC-DC converter through the power feeder to form a power loop, thereby generating a voltage drop on the cable corresponding to the set power, and thus obtaining the voltage drop generated by the long cable.

2. The system according to claim 1, characterized in that, The DC-AC converter includes a three-phase four-arm inverter, which outputs three phases A, B, and C and an external neutral line at the midpoint of each arm.

3. The system according to claim 1, characterized in that, The integrated power supply system for long cable power supply voltage drop measurement and voltage regulation further includes: a display and control device connected to the digital controller, used to set a power-time list in voltage drop measurement mode, and automatically perform duration tests for different power conditions according to the power-time list, generate reports and display them; and to display the system status and adjust the output voltage in voltage regulation mode.

4. The system according to claim 1, characterized in that, When the DC-AC converter operates in voltage regulation mode, the output terminal of the DC-AC converter is directly connected to the load.

5. The system according to claim 1, characterized in that, The digital controller is further used to control the connection method of the output terminal of the DC-AC converter to be compatible with single-phase or three-phase power grids.

6. The system according to claim 5, characterized in that, When the DC-AC converter measures the cable voltage drop under a three-phase power grid, the three-phase cable output by the DC-AC converter is connected to the corresponding positions A, B, and C of the three-phase power grid at the front end of the long cable.

7. The system according to claim 5, characterized in that, When the DC-AC converter measures the cable voltage drop under a single-phase power grid, one of the three phases output by the DC-AC converter is connected to the corresponding position at the front end of the long cable, and a neutral wire is led out from the front end of the long cable connected to the N phases to the system.

8. The system according to claim 1, characterized in that, The integrated power supply system for measuring and stabilizing voltage drop of long cable power supply further includes two relay switches, S1 and S2. S1 and S2 are set on the external neutral line to realize different circuit configurations and match various scenarios such as single-phase input and three-phase output, three-phase input and single-phase output, and three-phase input and output.

9. A power supply method integrating voltage drop measurement and voltage stabilization functions for long cable power supply, characterized in that, The integrated power supply system for measuring and regulating voltage drop of long cable power supply according to any one of claims 1-8 includes: When the integrated power supply system for long cable power supply voltage drop measurement and voltage regulation is operating in voltage regulation mode, the AC-DC converter provides a stable DC voltage to the DC-AC converter and completes power factor correction; the DC-AC converter independently outputs a stable AC voltage to the load. When the DC-AC converter operates in voltage drop measurement mode under the control of the digital controller, it is used to acquire the voltage at the front end and rear end of the long cable and calculate the voltage drop. The power-time list is set in voltage drop measurement mode by displaying the control device, and the duration test of different power conditions is automatically performed according to the power-time list, generating reports and displaying them.

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