Adjustable load system compatible with three-phase single-phase and direct current and method for regulating load

Abstract

The application relates to the technical field of electrical test, in particular to a compatible three-phase single-phase and DC adjustable load system and a load adjusting method. The system comprises a three-phase input switch, an input side of the three-phase input switch is connected with a three-phase alternating current input port, each item of an output side of the three-phase input switch is connected with a three-phase voltage bus, and a zero line is connected with a zero bus; a double-path low-voltage input switch, input sides of the double-path low-voltage input switch are respectively connected with positive and negative poles of a direct current input port, and an output side of the double-path low-voltage input switch is connected with an input port of a parallel-phase switch and the zero bus; the parallel-phase switch, an output end of the parallel-phase switch comprises three ports, and the output end of the parallel-phase switch is connected to the three-phase voltage bus; a double-path high-voltage input switch, input sides of the double-path high-voltage input switch are connected in parallel with the input sides of the double-path low-voltage input switch, and an output side T is connected to any two phases in the three-phase voltage bus; and a plurality of groups of parallel three-phase impedance loads.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrical test, in particular to a compatible three-phase single-phase and DC adjustable load system and a method for adjusting load. BACKGROUND

[0002] In the development, production and test process of various power equipment such as transformers, converters, battery packs, chargers and other equipment, load test is usually required to detect and evaluate the load capacity, performance indicators and reliability of the equipment under different working conditions, so it is necessary to configure a load system matched with the characteristics of the measured object. However, in the production practice, the tested equipment may be three-phase, single-phase or DC, and the output voltage and current range may have large differences, so the load system needs to be able to adapt to different types, voltage inputs and flexible adjustable loads. For example, there are many types of power grid ice melting devices, such as three-phase alternating current type, single-phase alternating current type, uncontrolled rectification type, wide amplitude voltage conversion type, etc. The output voltage and current of each type vary greatly. During the debugging and maintenance of ice melting equipment, it is often necessary to test under various output voltages and load currents, so a large power load compatible with multiple types of voltage, different amplitude voltage and different size current is required.

[0003] In view of the different working condition load test requirements, the traditional way is to configure three-phase alternating current load, single-phase or DC load for different measured units with different port characteristics, which will lead to the need to configure a large number of impedance loads in the test platform, occupying a large area and having high total cost. SUMMARY

[0004] The purpose of the embodiment of the present application is to provide a compatible three-phase single-phase and DC adjustable load system, which can adapt to different AC / DC and different input voltages and load currents through switching without increasing the rated power of the load in detail, thereby meeting the test requirements of different equipment.

[0005] In order to achieve the above purpose, the present application provides a compatible three-phase single-phase and DC adjustable load system, which comprises:

[0006] A three-phase input switch, the input side of the three-phase input switch is connected with a three-phase alternating current input port, and each item of the output side of the three-phase input switch is connected with a three-phase voltage bus, and the zero line of the three-phase input switch is connected with a zero bus;

[0007] A two-way low-voltage input switch, the input side of the two-way low-voltage input switch is connected with the positive and negative poles of a DC input port respectively, and the output side of the two-way low-voltage input switch is connected with the input port of a parallel switch and a zero bus;

[0008] The output end of the parallel-phase switch includes three ports, and the output end of the parallel-phase switch is connected to the three-phase voltage bus;

[0009] The input side of the dual-path high-voltage input switch is connected in parallel with the input side of the dual-path low-voltage input switch, and the output side T of the dual-path high-voltage input switch is connected to any two phases of the three-phase voltage bus.

[0010] The three-phase impedance loads in parallel include star-connected three-phase symmetric impedance units, and the input side of the three-phase impedance loads is connected to the load switching switch and the three-phase voltage bus.

[0011] In the embodiment of the present application, the adjustable load system compatible with three-phase single-phase and direct current further includes: a dual-path low-voltage input switch, the input side of the dual-path low-voltage input switch is connected to the zero line and the live wire of the one-way input port respectively, and the output side of the dual-path low-voltage input switch is connected to the input port of the parallel-phase switch and the zero bus.

[0012] In the embodiment of the present application, an interlocking circuit is arranged between the dual-path high-voltage input switch and the dual-path low-voltage input switch to prohibit the simultaneous closing of the dual-path high-voltage input switch and the dual-path low-voltage input switch; an interlocking circuit is arranged between the dual-path high-voltage input switch and the three-phase input switch to prohibit the simultaneous closing between the dual-path high-voltage input switch and the three-phase input switch; an interlocking circuit is arranged between the dual-path low-voltage input switch and the three-phase input switch to prohibit the simultaneous closing between the dual-path low-voltage input switch and the three-phase input switch; an interlocking circuit is arranged between the three-phase input switch and the parallel-phase switch to prohibit the simultaneous closing between the three-phase input switch and the parallel-phase switch; and an interlocking circuit is arranged between the dual-path high-voltage input switch and the parallel-phase switch to prohibit the simultaneous closing between the dual-path high-voltage input switch and the parallel-phase switch.

[0013] In the embodiment of the present application, the load switching switch includes a linkage load switching switch and a split-phase load switching switch, and the load of the adjustable load system compatible with three-phase single-phase and direct current is adjusted by controlling the linkage load switching switch and / or the split-phase load switching switch.

[0014] In the embodiment of the present application, the dual-path low-voltage input switch includes an overvoltage protection device.

[0015] In the embodiment of the present application, for any one of the three-phase impedance loads, the minimum current of each impedance unit included in the three-phase impedance load is less than or equal to a preset minimum load current, wherein the preset minimum load current is determined according to the minimum input voltage; and the sum of the total currents of all the three-phase impedance loads is greater than or equal to a preset maximum load current, wherein the preset maximum load current is determined according to the maximum input voltage.

[0016] The second aspect of the application provides a method for adjusting a load, applied to the compatible three-phase single-phase and DC adjustable load system of any one of the above, the method comprising:

[0017] According to the input voltage of the compatible three-phase single-phase and DC adjustable load system, the three-phase input switch, the double-path low-voltage input switch, the double-path high-voltage input switch, the parallel switch, and the load on-off switch corresponding to the plurality of groups of parallel three-phase impedance loads are controlled, so that the load of the adjustable load system is within a preset value range, wherein the preset value range is determined according to the input voltage.

[0018] In the embodiment of the application, the method comprises: in the case that the input voltage is the voltage provided by the three-phase power supply device, controlling the three-phase input switch to be closed, and the double-path low-voltage input switch, the double-path high-voltage input switch, and the parallel switch to be opened; controlling the plurality of load on-off switches included in the plurality of groups of parallel three-phase impedance loads to adjust the first load current of the compatible three-phase single-phase and DC adjustable load system, so that the first load current reaches the first preset load current corresponding to the three-phase power supply device.

[0019] In the embodiment of the application, the method comprises: in the case that the input voltage is the voltage provided by the single-phase power supply device, acquiring the input voltage of the single-phase power supply device; in the case that the input voltage is lower than the load resistance rated phase voltage of the compatible three-phase single-phase and DC adjustable load system, controlling the double-path low-voltage input switch and the parallel switch to be closed, and the three-phase input switch and the double-path high-voltage input switch to be opened; controlling the plurality of load on-off switches included in the plurality of groups of parallel three-phase impedance loads to adjust the second load current of the compatible three-phase single-phase and DC adjustable load system, so that the second load current reaches the second preset load current corresponding to the single-phase power supply device; in the case that the input voltage is higher than the load resistance rated phase voltage and lower than the preset multiple of the load resistance rated phase voltage, controlling the double-path high-voltage input switch to be closed, and the double-path low-voltage input switch, the parallel switch, and the three-phase input switch to be opened; controlling the plurality of load on-off switches included in the plurality of groups of parallel three-phase impedance loads to adjust the third load current of the compatible three-phase single-phase and DC adjustable load system, so that the third load current reaches the third preset load current corresponding to the single-phase power supply device.

[0020] In the embodiment of the present application, the method comprises: obtaining the input voltage of the DC power supply device in the case that the input voltage is the voltage provided by the DC power supply device; controlling the double-path low-voltage input switch and the parallel-phase switch to be closed and the three-phase input switch and the double-path high-voltage input switch to be opened in the case that the input voltage is lower than the rated phase voltage of the load resistance of the compatible three-phase single-phase and DC adjustable load system; controlling the multiple load on-off switches included in the multiple groups of parallel three-phase impedance loads to adjust the fourth load current of the compatible three-phase single-phase and DC adjustable load system so that the fourth load current reaches the fourth preset load current corresponding to the DC power supply device; controlling the double-path high-voltage input switch to be closed and the double-path low-voltage input switch, the parallel-phase switch and the three-phase input switch to be opened in the case that the input voltage is higher than the rated phase voltage of the load resistance and lower than the preset multiple of the rated phase voltage of the load resistance; and controlling the multiple load on-off switches included in the multiple groups of parallel three-phase impedance loads to adjust the fifth load current of the compatible three-phase single-phase and DC adjustable load system so that the fifth load current reaches the fifth preset load current corresponding to the DC power supply device.

[0021] Through the above technical solution, the compatible three-phase single-phase and DC adjustable load system can be compatible with three-phase input, single-phase input, DC input, high-voltage large current or low-voltage small current and other working conditions. When switching different input modes, only a small number of switches need to be adjusted, which is convenient and efficient, avoiding tedious reconnection work and being high in efficiency.

[0022] Other features and advantages of the embodiments of the present application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings are included to provide a further understanding of the embodiments of the present application, and constitute a part of the specification, and are used together with the following specific embodiments to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. In the drawings:

[0024] Figure 1 The structure of the compatible three-phase single-phase and DC adjustable load system according to the embodiment of the present application is schematically shown;

[0025] Figure 2 The running state diagram of each switch unit when the compatible three-phase single-phase and DC adjustable load system inputs three-phase unbalanced load according to the embodiment of the present application is schematically shown;

[0026] Figure 3 The running state diagram of each switch when the compatible three-phase single-phase and DC adjustable load system inputs voltage lower and with maximum output current according to the embodiment of the present application is schematically shown;

[0027] Figure 4A switching state diagram of each switch when the input voltage of the adjustable load system compatible with three-phase single-phase and direct current is high and with partial load is schematically shown according to the embodiment of the application.

[0028] Legend of reference signs

[0029] K1: three-phase input switch; K2: two-way low-voltage input switch; K3: parallel-phase switch; K4: two-way high-voltage input switch; R1, R2, R3: three-phase impedance load; A, B, C: three-phase voltage bus; N: zero bus; K11, K12, K13: linkage load on-off switch; K12a, K12b, K12c, K13c: separate-phase load on-off switch; V+: direct current positive input port; V-: direct current negative input port; I: single-phase firewire input port; N: single-phase zero line input port. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. It should be understood that the specific embodiments described herein are merely used to explain and illustrate the embodiments of the present application and should not be used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0031] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are merely used to explain the relative positional relationship, motion condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directional indications also change accordingly.

[0032] In addition, if the embodiments of the present application involve descriptions of “first”, “second”, etc., the descriptions of “first”, “second”, etc. are merely for description purposes and should not be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by “first”, “second” can explicitly or implicitly include at least one of the features. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize it, and when the combination of technical solutions appears to be contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the scope of protection claimed by the present application.

[0033] Figure 1 A structure schematic diagram of an adjustable load system compatible with three-phase single-phase and direct current according to the embodiment of the present application is schematically shown. As shown in the figure, Figure 1As shown, the embodiment of the present application provides a compatible three-phase single-phase and DC adjustable load system, which can include: a three-phase input switch K1, the input side of the three-phase input switch K1 is connected with a three-phase alternating current input port, the output side of the three-phase input switch K1 is respectively connected with three-phase voltage buses A, B and C, and the zero line of the three-phase input switch K1 is connected with a zero bus N; a two-way low-voltage input switch K2, the input side of the two-way low-voltage input switch K2 is respectively connected with the positive electrode V+ and the negative electrode V- of a direct current input port, the output side of the two-way low-voltage input switch K2 is connected with the input port of a parallel switch K3 and the zero bus N; the parallel switch K3, the output end of the parallel switch K3 includes three ports, and the output end of the parallel switch K3 is connected to the three-phase voltage buses A, B and C; a two-way high-voltage input switch K4, the input side of the two-way high-voltage input switch K4 is parallel to the input side of the two-way low-voltage input switch K2, and the output side T of the two-way high-voltage input switch K4 is connected to any two of the three-phase voltage buses A, B and C; and a plurality of groups of parallel three-phase impedance loads, each group of three-phase impedance loads includes a star-connected three-phase symmetric impedance load, the input side of the three-phase impedance load is connected with a load on-off switch and connected to the three-phase voltage buses A, B and C, and the common point of the star-connected three-phase impedance load is connected to the zero bus N.

[0034] For example Figure 1 As shown, assuming that the compatible three-phase single-phase and DC adjustable load system includes three groups of parallel three-phase impedance loads R1, R2 and R3, each group of three-phase impedance loads includes a star-connected three-phase symmetric impedance unit, the input side of the three-phase impedance load is connected with a load on-off switch, for example Figure 1 As shown, the input side of the three-phase impedance load R1 is connected with a load on-off switch K11 and connected to the three-phase voltage buses A, B and C through the load on-off switch K11, and the common point of the star-connected three-phase impedance load R1 is connected to the zero bus N. The input side of the three-phase impedance load R2 is connected with a load on-off switch K12 and connected to the three-phase voltage buses A, B and C through the load on-off switch K12, and a load on-off switch can be connected between the output side of the load on-off switch K12 and the three-phase voltage buses A, B and C, for example Figure 1 As shown, the output side of the load on-off switch K12 is connected with a load on-off switch K12a between the three-phase voltage bus A, the output side of the load on-off switch K12 is connected with a load on-off switch K12b between the three-phase voltage bus B, the output side of the load on-off switch K12 is connected with a load on-off switch K12c between the three-phase voltage bus C, and the common point of the star-connected three-phase impedance load R1 is connected to the zero bus N. The input side of the three-phase impedance load R3 is connected with a load on-off switch K13, and a load on-off switch can be connected between the output side of the load on-off switch K13 and any one of the three-phase voltage buses A, B and C, for example Figure 1As shown, the output side of the load switching switch K13 is connected with the load switching switch K13c between the three-phase voltage bus C, and the common point of the star connection of the three-phase impedance load R1 is connected to the zero bus N. The adjustable load system compatible with three-phase single-phase and DC can connect multiple different load switching switches at the input side of multiple three-phase impedance loads, so as to adjust the size of the load current by switching the load switching switches of each three-phase impedance load, so that the size of the load current reaches the preset value set by the user or the expected value required by the user.

[0035] In one embodiment, the load switching switch includes a linkage switch and a split-phase switch, and the load of the adjustable load system compatible with three-phase single-phase and DC is adjusted by controlling the linkage switch and / or the split-phase switch.

[0036] For example Figure 1 As shown, the load switching switch can include linkage load switching switches K11, K12, K13, and split-phase load switching switches K12a, K12b, K12c, K13c. For example, when testing a three-phase balanced load, each group of three-phase impedance load corresponding split-phase load switching switches K12a, K12b, K12c, K13c are closed at the same time, and different load current sizes are obtained by closing linkage load switching switches K11, K12, K13 respectively. When testing a three-phase unbalanced load, according to the required unbalanced load type and size, linkage load switching switches K11, K12, K13 and split-phase load switching switches K12a, K12b, K12c, K13c can be controlled to be closed at the same time to obtain the required unbalanced load current.

[0037] In one embodiment, as Figure 1 As shown, the adjustable load system compatible with three-phase single-phase and DC further includes a two-way low-voltage input switch K2, the input side of the two-way low-voltage input switch K2 is connected with the zero line N and the live wire I of the single-phase input port respectively, and the output side of the two-way low-voltage input switch K2 is connected with the input port of the parallel switch K3 and the zero bus N.

[0038] The two-way input port included in the adjustable load system compatible with three-phase single-phase and DC can be used as the input port of the zero line N and the live wire I of the one-way input port, or as the input port of the positive V+ and negative V- of the DC input port. The input side of the two-way low-voltage input switch K2 can be connected with the two-way input port, and the output side is connected with the input port of the parallel switch K3 and the zero bus N.

[0039] In one embodiment, as Figure 1As shown, the input switching switch is formed between the double-path high-voltage input switch K4, the three-phase input switch K1, the double-path low-voltage input switch K2 and the parallel-phase switch K3, and is provided with a false closing prevention locking circuit. An interlocking circuit is arranged between the double-path high-voltage input switch K4 and the double-path low-voltage input switch K2 to prohibit the double-path high-voltage input switch K4 and the double-path low-voltage input switch K2 from being closed at the same time. An interlocking circuit is arranged between the double-path high-voltage input switch K4 and the three-phase input switch K1 to prohibit the double-path high-voltage input switch K4 and the three-phase input switch K1 from being closed at the same time. An interlocking circuit is arranged between the double-path low-voltage input switch K2 and the three-phase input switch K1 to prohibit the double-path low-voltage input switch K2 and the three-phase input switch K1 from being closed at the same time. An interlocking circuit is arranged between the three-phase input switch K1 and the parallel-phase switch K3 to prohibit the three-phase input switch K1 and the parallel-phase switch K3 from being closed at the same time. An interlocking circuit is arranged between the double-path high-voltage input switch K4 and the parallel-phase switch K3 to prohibit the double-path high-voltage input switch K4 and the parallel-phase switch K3 from being closed at the same time.

[0040] In one embodiment, the double-path low-voltage input switch comprises an overvoltage protection device.

[0041] The double-path low-voltage input switch K2 in the adjustable load system compatible with three-phase single-phase and DC is provided with an overvoltage protection device (not shown in the figure). The overvoltage protection device is set to be compatible with the highest voltage that the load impedance in the adjustable load system compatible with three-phase single-phase and DC can withstand. When it is detected that the input side voltage exceeds the set low input voltage rating, the double-path low-voltage input switch K2 is prohibited from closing or is tripped immediately after closing, so as to avoid damage to the low-voltage side load caused by the mis-closing of the double-path low-voltage input switch K2 when the input voltage is high. Further, in the adjustable load system compatible with three-phase single-phase and DC, an overcurrent fuse can be arranged in the loop where the parallel switch is located, so as to prevent the input power from being directly short-circuited due to the simultaneous closing of the parallel-phase switch K3 and the double-path high-voltage input switch K4, or the simultaneous closing of the parallel-phase switch K3 and the three-phase input switch K1.

[0042] In one embodiment, for any one group of three-phase impedance loads, the minimum current of each impedance unit included in the three-phase impedance load is less than or equal to a preset minimum load current, wherein the preset minimum load current is determined according to the minimum input voltage; and the sum of the total currents of all the three-phase impedance loads is greater than or equal to a preset maximum load current, wherein the preset maximum load current is determined according to the maximum input voltage.

[0043] In one embodiment, a method for adjusting a load is provided, which is applied to the adjustable load system compatible with three-phase single-phase and DC as described above. Figure 1The adjustable load system shown is compatible with three-phase, single-phase, and DC. The method includes: controlling the three-phase input switch K1, the dual-channel low-voltage input switch K2, the dual-channel high-voltage input switch K4, the parallel phase switch K3, and the load on / off switches corresponding to multiple sets of parallel three-phase impedance loads according to the input voltage of the adjustable load system, so that the load of the adjustable load system is within a preset value range, wherein the preset value range is determined according to the input voltage.

[0044] The adjustable load system, compatible with three-phase, single-phase, and DC, can connect to different power supply devices under test. Based on the input voltage provided by the power supply device under test, the system controls the load on / off switches corresponding to the three-phase input switch K1, the dual low-voltage input switch K2, the dual high-voltage input switch K4, the parallel phase switch K3, and multiple sets of parallel three-phase impedance loads, so that the load of the adjustable load system is within a preset value range corresponding to the input voltage, thereby determining the load capacity of the power supply device corresponding to the input voltage.

[0045] In one embodiment, the method includes: when the input voltage is the voltage provided by the three-phase power supply device, controlling the three-phase input switch to close, and the dual-channel low-voltage input switch, dual-channel high-voltage input switch and parallel phase switch to open; controlling multiple load on / off switches including multiple sets of parallel three-phase impedance loads to adjust the first load current of the adjustable load system compatible with three-phase single-phase and DC, so that the first load current reaches the first preset load current corresponding to the three-phase power supply device.

[0046] like Figure 1 The adjustable load system shown, compatible with three-phase, single-phase, and DC, can control the three-phase input switch K1 to close and the dual-channel low-voltage input switch K2, dual-channel high-voltage input switch K4, and parallel-phase switch K3 to open when the input voltage is the voltage provided by the three-phase power supply equipment. It can control multiple load on / off switches of multiple sets of parallel storage box impedance loads to adjust the first load current of the adjustable load system compatible with three-phase, single-phase, and DC, so that the first load current reaches the first preset load current corresponding to the three-phase power supply equipment.

[0047] For example Figure 2 The diagram illustrates the operating status of various switches within the three-phase, single-phase, and DC-compatible adjustable load system. This is done when the input voltage is provided by a three-phase power supply, and the three-phase input switch K1 is closed, and the load switching switches K11, K12, and K13 (including the load switching switches K11, K12, and K13c) of the three-phase impedance load R1 are closed, while K12b and K12c are open to form a three-phase unbalanced load.

[0048] In one embodiment, the method comprises: obtaining an input voltage of a single-phase power supply device in the case that the input voltage is a voltage provided by the single-phase power supply device; controlling the closing of a double low-voltage input switch and a parallel-phase switch and the opening of a three-phase input switch and a double high-voltage input switch in the case that the input voltage is lower than a load resistance rated phase voltage of a three-phase single-phase and DC compatible adjustable load system; controlling a plurality of load on-off switches included in a plurality of groups of parallel three-phase impedance loads to adjust a second load current of the three-phase single-phase and DC compatible adjustable load system, so that the second load current reaches a second preset load current corresponding to the single-phase power supply device; controlling the closing of the double high-voltage input switch and the opening of the double low-voltage input switch, the parallel-phase switch and the three-phase input switch in the case that the input voltage is higher than the load resistance rated phase voltage and lower than a preset multiple of the load resistance rated phase voltage; and controlling the plurality of load on-off switches included in the plurality of groups of parallel three-phase impedance loads to adjust a third load current of the three-phase single-phase and DC compatible adjustable load system, so that the third load current reaches a third preset load current corresponding to the single-phase power supply device.

[0049] In one embodiment, the method comprises: obtaining an input voltage of a DC power supply device in the case that the input voltage is a voltage provided by the DC power supply device; controlling the closing of a double low-voltage input switch and a parallel-phase switch and the opening of a three-phase input switch and a double high-voltage input switch in the case that the input voltage is lower than a load resistance rated phase voltage of a three-phase single-phase and DC compatible adjustable load system; controlling a plurality of load on-off switches included in a plurality of groups of parallel three-phase impedance loads to adjust a fourth load current of the three-phase single-phase and DC compatible adjustable load system, so that the fourth load current reaches a fourth preset load current corresponding to the DC power supply device; controlling the closing of the double high-voltage input switch and the opening of the double low-voltage input switch, the parallel-phase switch and the three-phase input switch in the case that the input voltage is higher than the load resistance rated phase voltage and lower than a preset multiple of the load resistance rated phase voltage; and controlling the plurality of load on-off switches included in the plurality of groups of parallel three-phase impedance loads to adjust a fifth load current of the three-phase single-phase and DC compatible adjustable load system, so that the fifth load current reaches a fifth preset load current corresponding to the DC power supply device.

[0050] In the case that the input voltage is a voltage provided by a single-phase power supply device or in the case that the input voltage is a voltage provided by a DC power supply device, the input voltage of the single-phase power supply device or the voltage of the DC power supply device can be obtained, and in the case that the input voltage is lower than a load resistance rated phase voltage of a three-phase single-phase and DC compatible adjustable load system, the three-phase single-phase and DC compatible adjustable load system as shown in Figure 3 can control the closing of a double low-voltage input switch K2 and a parallel-phase switch K3 and the opening of a three-phase input switch K1 and a double high-voltage input switch K4, and control a plurality of load on-off switches included in a plurality of groups of parallel three-phase impedance loads, for example Figure 3As shown, when the compatible three-phase single-phase and DC adjustable load system is the maximum load, the load switching K11, K12, K13, K12a, K12b, K12c and K13c are all closed, so as to obtain the running state of each switch unit in the compatible three-phase single-phase and DC adjustable load system with low input voltage and maximum load.

[0051] In the case that the input voltage is higher than the rated phase voltage of the load resistor and lower than the preset multiple of the rated phase voltage of the load resistor, for example, assuming that the preset multiple is set to two, that is, the input voltage is higher than the rated phase voltage of the load resistor and lower than twice the rated phase voltage of the load resistor, as shown in the compatible three-phase single-phase and DC adjustable load system, Figure 4 As shown, the compatible three-phase single-phase and DC adjustable load system can control the double-way high-voltage input switch K4 to be closed, the double-way low-voltage input switch K2, the parallel switch K3 and the three-phase input switch K1 to be disconnected, and can control a plurality of load switching included in a plurality of parallel three-phase impedance loads to adjust the fifth load current of the compatible three-phase single-phase and DC adjustable load system, for example Figure 4 As shown, the load switching K11, K12, K13, K12b, K12c are controlled to be closed, so as to obtain the running state of each switch unit in the compatible three-phase single-phase and DC adjustable load system with high input voltage and partial load.

[0052] The above technical scheme, the compatible three-phase single-phase and DC adjustable load system can be compatible with three-phase input, single-phase input, DC input, high-voltage large current or low-voltage small current and other working conditions. In different input modes, the maximum output power can be obtained approximately, so as to avoid the case that the power is seriously reduced and the power utilization rate is extremely low in some working conditions, improve the power component utilization rate, and be beneficial to reduce the volume and weight of the load system and the cost, and improve the economy. When switching different input modes, only a small amount of switches need to be adjusted, which is convenient and fast, avoids complicated wiring work, and has high efficiency. The anti-misoperation interlocking system is provided, which can prevent abnormal failure caused by misoperation of the operator to cause damage to the equipment.

[0053] In one embodiment, the parameter configuration of the required load is explained in combination with an actual test case. The devices required for the load test include: a three-phase alternating current ice melting device with a rated output of 400V / 600A / 400kVA, a single-phase alternating current ice melting device with a rated output of 220V / 600A / 132kVA, a small DC ice melting device with a rated output of 80V / 500A / 40kW, and a pickup type DC ice melting device with a rated output of 600A / 500V / 300kW.

[0054] In order to meet the test needs of the above four types of devices, the parameters of each component designed according to the present application are as follows:

[0055] Three-phase AC input switch is designed according to the maximum three-phase load voltage and current to be tested, and the rated parameters of the low-voltage three-phase four-wire molded case circuit breaker are 630A / 400V respectively.

[0056] Dual high-voltage input switch is designed according to the maximum input phase voltage or DC voltage that may occur, and its current-carrying capacity is designed according to the maximum total load current to be tested, and the rated parameters of the low-voltage molded case circuit breaker are 0A / 600V.

[0057] Dual low-voltage input switch is designed according to the maximum input phase voltage or DC voltage that may occur, and its current-carrying capacity is designed according to the maximum total load current to be tested, and the rated parameters of the low-voltage molded case circuit breaker are 0A / 600V.

[0058] Parallel switch is designed according to the highest input three-phase line voltage or DC voltage that can be withstood, and its current-carrying capacity is designed according to the maximum total load current to be tested when three phases are connected in parallel, and the rated parameters of the three-phase low-voltage molded case circuit breaker are 400A / 600V.

[0059] Load impedance is divided into 7 groups, and star connection is used between three-phase impedance in each group. The rated voltage of each phase impedance is 230V, and the highest voltage is 120% overload. The impedance parameters are designed according to the branch load power and current of 6kW, 12kW, 12kW, 30kW, 60kW, 120kW and 200kW respectively when converted to the rated voltage 230V. The corresponding load switches are marked as Kf1, Kf2, K3, Kf4, Kf5, Kf6 and Kf7 respectively. The total rated output power is 440kW when the input three-phase voltage is 4000V and each load switch is put into. When the input voltage fluctuates by 120%, the maximum load power of 633kW can be provided.

[0060] When testing the rated output 400V / 600A / 400kVA three-phase AC ice-melting device, the three-phase output port of the measured device is connected to the three-phase AC input port of the load system, the three-phase input switch K1 is closed, the double-path high-voltage input switch K4, the parallel-phase switch K3, and the double-path low-voltage input switch K2 are disconnected; the phase control switches in each load impedance are closed at the same time, and the size of the load current is adjusted to the expected value by switching the load on-off switch of each load impedance. For example, in order to test the 400kW rated power, 12kW, 12kW, 60kW, 120kW, 200kW, a total of 5 groups of loads are put in to obtain the nominal 404kW load power; or 6kW, 12kW, 60kW, 120kW, 200kW, a total of 5 groups of loads are put in to obtain the nominal 398kW load power. When testing the three-phase unbalanced load, for example, 50kW, 0kW, 0kW load in A phase, B phase, and C phase, respectively, 12kW, 30kW, 60kW, 120kW, 200kW load impedance in three-phase load switches can be put in, but all the A-phase switches in the five switches and the C-phase switch corresponding to the 120kW load are turned off, and the nominal load power can be obtained.

[0061] When testing the rated output 220V / 600A / 132kVA single-phase AC ice-melting device, the output firewire and zero line of the measured device are connected to the double-loop input port of the load system, the double-path high-voltage input switch K4 and the three-phase input switch K1 are disconnected, the parallel-phase switch K3 and the double-path low-voltage input switch K2 are closed. The phase control switches in all 7 groups of load impedances are closed at the same time, and the size of the load current is adjusted to the expected value by switching the load on-off switch of each load impedance. For example, under 220V voltage, the load power corresponding to each group of impedance is 5.4kW, 10.9kW, 10.9kW, 27.2kW, 54.5kW, 108.9kW, and 181.6kW. In order to obtain 132kW power under 220V input, Kf2, K3, and Kf6, a total of 3 groups of loads can be put in to obtain the nominal 131kW load power. When the actual output power deviates from the expected value, the required load power can be obtained by fine-tuning the small load switch.

[0062] When testing the rated output 80V / 500A / 40kW of the DC de-icing device, the positive and negative poles of the measured device are connected to the double-loop input port of the load system, the double-loop high-voltage input switch K4 and the three-phase input switch K1 are disconnected, and the parallel switch K3 and the double-loop low-voltage input switch K2 are closed. The split-phase control switches in all 7 groups of load impedances are closed at the same time, and the load current is adjusted to the expected value by turning on and off the load switches of each load impedance. For example, under 220V voltage, the load power corresponding to each group of impedance is 0.7kW, 1.4kW, 1.4kW, 3.6kW, 7.2kW, 14.4kW, and 24.0kW, with a total of 52.8kW power. For example, in order to test the rated power of 80V / 500A / 40kW, 3 groups of Kf2, Kf6, and Kf7 can be turned on to obtain the nominal 39.8kW load power. When the actual output power deviates from the expected value, the load power close to the required load power can be obtained by fine-tuning the small load switch.

[0063] When testing the rated output 500V / 600A / 300kW of the DC de-icing device, the positive and negative poles of the measured device are connected to the double-loop input port of the load system, the double-loop high-voltage input switch K4 is closed, the three-phase input switch K1, the parallel switch K3, and the double-loop low-voltage input switch K2 are disconnected, and the rated output DC voltage 500V is applied to the bus voltage. At this time, although it exceeds the rated voltage of each impedance 230V*2=460V, it has not exceeded the highest voltage 230V*2*120%=520V, and each device can withstand overload operation. For example, under 500V voltage, the load power corresponding to each group of impedance is 4.7kW, 9.4kW, 9.4kW, 18.8kW, 46.9kW, 93.8kW, and 156.3kW, with a total of 343kW power. The split-phase control switches in all 7 groups of load impedances are closed at the same time, and the load current is adjusted to the expected value by turning on and off the load switches of each load impedance. For example, in order to test the rated power of 500V / 600A / 300kW, 3 groups of Kf5, Kf6, and Kf7 can be turned on to obtain the nominal 297kW load power. When the actual output power deviates from the expected value, the load power close to the required load power can be obtained by fine-tuning the small load switch.

[0064] Those skilled in the art will appreciate that embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects.

[0065] It should also be noted that the terms "comprising", "comprises" or other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0066] The above embodiments are only used to illustrate the present application, but not to limit it. Instead of the above, various modifications and changes can be made to the application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall fall into the scope of the claims of the application.

Claims

1. An adjustable load system compatible with three-phase, single-phase, and DC, characterized in that, The adjustable load system compatible with three-phase, single-phase, and DC includes: A three-phase input switch, wherein the input side of the three-phase input switch is connected to a three-phase AC input port, each of the outputs of the three-phase input switch is connected to a three-phase voltage bus, and the neutral line of the three-phase input switch is connected to a neutral bus. A dual-channel low-voltage input switch, wherein the input side of the dual-channel low-voltage input switch is connected to the positive and negative terminals of the DC input port respectively, and the output side of the dual-channel low-voltage input switch is connected to the input port of the parallel phase switch and the neutral bus. The parallel phase switch has three output ports, and all output ports of the parallel phase switch are connected to the three-phase voltage bus. A dual-channel high-voltage input switch, wherein the input side of the dual-channel high-voltage input switch is connected in parallel with the input side of the dual-channel low-voltage input switch, and the output side T of the dual-channel high-voltage input switch is connected to any two phases of the three-phase voltage bus; and Multiple sets of parallel three-phase impedance loads, each set of three-phase impedance loads includes a star-connected three-phase symmetrical impedance unit. The input side of the three-phase impedance load is connected to the load switching switch and to the three-phase voltage bus. The common point of the star-connected three-phase impedance load is connected to the zero bus.

2. The adjustable load system compatible with three-phase, single-phase, and DC as described in claim 1, characterized in that, The adjustable load system compatible with three-phase, single-phase, and DC also includes: The dual-channel low-voltage input switch has its input side connected to the neutral and live wires of the unidirectional input port, respectively, and its output side connected to the input port of the parallel phase switch and the neutral bus.

3. The adjustable load system compatible with three-phase, single-phase, and DC as described in claim 1, characterized in that, An interlock circuit is provided between the dual-channel high-voltage input switch and the dual-channel low-voltage input switch to prevent the dual-channel high-voltage input switch and the dual-channel low-voltage input switch from closing simultaneously. An interlock circuit is provided between the dual-channel high-voltage input switch and the three-phase input switch to prevent the dual-channel high-voltage input switch and the three-phase input switch from closing simultaneously. An interlock circuit is provided between the dual-channel low-voltage input switch and the three-phase input switch to prevent the dual-channel low-voltage input switch and the three-phase input switch from closing simultaneously. An interlock circuit is provided between the three-phase input switch and the parallel phase switch to prevent the three-phase input switch and the parallel phase switch from closing simultaneously. An interlock circuit is provided between the dual-channel high-voltage input switch and the parallel-phase switch to prevent them from closing simultaneously.

4. The adjustable load system compatible with three-phase, single-phase, and DC as described in claim 1, characterized in that, The load switching includes a linkage load switching and a phase-by-phase load switching. The load of the adjustable load system compatible with three-phase, single-phase and DC can be adjusted by controlling the linkage load switching and / or the phase-by-phase load switching.

5. The adjustable load system compatible with three-phase, single-phase, and DC as described in claim 1, characterized in that, The dual-channel low-voltage input switch includes an overvoltage protection device.

6. The adjustable load system compatible with three-phase, single-phase, and DC as described in claim 1, characterized in that, For any set of three-phase impedance loads, the minimum current of each impedance element included in the three-phase impedance load is less than or equal to a preset minimum load current, wherein the preset minimum load current is determined based on the minimum input voltage; The sum of the total currents of all three-phase impedance loads is greater than or equal to the preset maximum load current, wherein the preset maximum load current is determined based on the maximum input voltage.

7. A method for adjusting load, characterized in that, Applied to an adjustable load system compatible with three-phase, single-phase, and DC as described in any one of claims 1 to 6, the method comprises: The three-phase input switch, the dual-channel low-voltage input switch, the dual-channel high-voltage input switch, the parallel phase switch, and the load on / off switches corresponding to multiple sets of parallel three-phase impedance loads are controlled according to the input voltage of the adjustable load system compatible with three-phase, single-phase, and DC, so that the load of the adjustable load system is within a preset value range, wherein the preset value range is determined according to the input voltage.

8. The method for adjusting load according to claim 7, characterized in that, The method includes: When the input voltage is the voltage provided by the three-phase power supply equipment, the three-phase input switch is closed, and the dual-channel low-voltage input switch, dual-channel high-voltage input switch and parallel-phase switch are opened. Controlling multiple sets of parallel three-phase impedance loads includes multiple load on / off switches to adjust the first load current of the adjustable load system compatible with three-phase, single-phase, and DC, so that the first load current reaches the first preset load current corresponding to the three-phase power supply equipment.

9. The method for adjusting load according to claim 7, characterized in that, The method includes: When the input voltage is the voltage provided by the single-phase power supply device, the input voltage of the single-phase power supply device is obtained; When the input voltage is lower than the rated phase voltage of the load resistance of the adjustable load system compatible with three-phase, single-phase, and DC, the dual-channel low-voltage input switch and the parallel-phase switch are closed, while the three-phase input switch and the dual-channel high-voltage input switch are opened. Controlling multiple sets of parallel three-phase impedance loads includes multiple load on / off switches to adjust the second load current of the adjustable load system compatible with three-phase, single-phase, and DC, so that the second load current reaches the second preset load current corresponding to the single-phase power supply equipment. When the input voltage is higher than the rated phase voltage of the load resistor but lower than a preset multiple of the rated phase voltage of the load resistor, the dual high-voltage input switch is closed, and the dual low-voltage input switch, the parallel phase switch, and the three-phase input switch are opened. Controlling multiple sets of parallel three-phase impedance loads includes multiple load on / off switches to adjust the third load current of the adjustable load system compatible with three-phase, single-phase, and DC, so that the third load current reaches the third preset load current corresponding to the single-phase power supply equipment.

10. The method for adjusting load according to claim 7, characterized in that, The method includes: When the input voltage is the voltage provided by the DC power supply device, the input voltage of the DC power supply device is obtained; When the input voltage is lower than the rated phase voltage of the load resistance of the adjustable load system compatible with three-phase, single-phase, and DC, the dual-channel low-voltage input switch and the parallel-phase switch are closed, while the three-phase input switch and the dual-channel high-voltage input switch are opened. Controlling multiple sets of parallel three-phase impedance loads includes multiple load on / off switches to adjust the fourth load current of the adjustable load system compatible with three-phase, single-phase and DC, so that the fourth load current reaches the fourth preset load current corresponding to the DC power supply equipment. When the input voltage is higher than the rated phase voltage of the load resistor but lower than a preset multiple of the rated phase voltage of the load resistor, the dual high-voltage input switch is closed, and the dual low-voltage input switch, the parallel phase switch, and the three-phase input switch are opened. The control of multiple sets of parallel three-phase impedance loads includes multiple load on / off switches to adjust the fifth load current of the adjustable load system compatible with three-phase, single-phase and DC, so that the fifth load current reaches the fifth preset load current corresponding to the DC power supply equipment.

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