Base station generator parallel operation control circuit and control system

Abstract

The invention provides a base station generator parallel operation control circuit and a control system, A, B and C phases of an alternating current distribution box or a three-phase generator are connected to input buses of three groups of modules of a combined switch power supply system after passing through a circuit breaker and a contactor, and input zero lines of the three groups of modules of the combined switch power supply system are combined into one phase after passing through the contactor; connecting the N phase of the AC distribution box or the three-phase generator; a live wire and a zero wire of each single-phase generator pass through a circuit breaker and a contactor and then are connected to an input bus and an input zero wire of each module of the combined switching power supply system. According to the invention, mutual physical isolation of zero lines of each single-phase generator can be realized, and the problem of generator tripping caused by zero-sequence current does not exist; the functions of automatic switching of zero lines, electrical and mechanical double interlocking protection of mains supply-generator power supply, signal indication, short-circuit protection, emergency shutdown and the like are achieved, the automation degree is higher, and safety is better.

Description

Technical Field

[0001] The invention belongs to the technical field of parallel generator control, and in particular relates to a base station generator parallel generator control circuit and control system. Background Art

[0002] A generator is a mechanical device that converts mechanical energy into electrical energy. It is driven by a turbine, steam turbine, diesel engine or other power machinery, and converts the energy generated by water flow, air flow, fuel combustion or nuclear fission into mechanical energy and transmits it to the generator, which then converts it into electrical energy. Generator paralleling means that when two or more generator sets are combined to supply power to the load, the theoretical power generation capacity is increased. It is necessary to install a generator paralleling device to ensure that the system can meet the requirements of joint power supply and make the generator work normally. The generator used in the base station is usually used for emergency power generation after the city power outage. It often uses gasoline or diesel combustion to convert it into mechanical energy and transmit it to the generator for power generation. When the rated capacity of a generator is less than the total load of the base station, the power generation cannot meet the power demand of the base station, and multiple generators are required to generate power in parallel to jointly supply power to the base station.

[0003] With the development of technologies such as 5G and edge computing, the load of base stations is also increasing. For some sites, the rated power of a single single-phase generator set is small and can no longer meet the power supply needs of base station equipment. If a high-power three-phase generator is used, it is large in size, heavy, and difficult to carry. For remote sites such as mountains and islands, it takes a long time to carry after a power outage, which may result in the inability to generate electricity in time. For such scenarios, multiple small single-phase generators can be connected simultaneously for parallel power generation to meet the power supply requirements of the site.

[0004] There are usually two existing base station generator parallel solutions:

[0005] 1. After the outputs of three single-phase generators are combined into a three-phase four-wire AC power, the back-end equipment is powered: the AC live wires of the three single-phase generators are the A, B, and C phases of the three-phase AC output, and the neutral wires of the three generators are directly connected in parallel and share the neutral wire. This solution has the following disadvantages: Because the modules of the combined switching power supply used in the base station are AC single-phase inputs, when the modules are not current-balanced or the number of three-phase modules is uneven, there will be an imbalance in the three-phase current, and the shared neutral wire will have excessive zero-sequence current, causing the generator to trip and protect, posing a hidden danger to safe operation.

[0006] 2. Rectify the AC output of multiple generators into DC power and connect them in parallel. Then, after boosting the voltage through a DC-DC converter, the DC power is uniformly inverted into three-phase AC power to supply power to the back-end equipment. This solution has the following disadvantages: through the three-stage power electronic conversion of rectification, DC-DC boost, and inversion, the power loss is serious and the conversion efficiency is low, which further reduces the power output.

[0007] Chinese invention patent CN110445187B proposes a parallel interlock control circuit and parallel interlock system, which controls the output power supply of two generators by connecting multiple contactors in series and parallel to form an electrical interlock circuit, ensuring that only one of the two generators can output power when an interlock signal is received. This circuit has the following disadvantages: (1) It is only used to control the switching between generators, and there is no switching protection for the mains-generator power supply; (2) There is only electrical interlock, no mechanical interlock, and the reliability is not high; (3) The circuit has no indication function and no short-circuit protection device, which poses a safety hazard.

[0008] In view of this, it is necessary to propose a new parallel control circuit and system to solve the above problems. Summary of the invention

[0009] In order to solve the common problems in the prior art, the present invention proposes a base station generator parallel control circuit and control system, in which three single-phase generators are respectively connected to three groups of modules of the combined switching power supply system, and different single-phase generators respectively supply power to the switching power supply modules connected to different phases. The neutral lines of each single-phase generator are physically isolated from each other, and there is no problem of zero-sequence current causing the generator to trip. The present invention improves operational safety by arranging power supply interlocking between the mains and the single-phase generator.

[0010] The technical solution adopted by the present invention is:

[0011] According to a first aspect, the present invention provides a base station generator parallel control circuit, which is used to control an AC distribution box or a three-phase generator to supply power through a combined switching power supply system, and to control three single-phase generators to supply power through a combined switching power supply system as a backup; comprising a first circuit breaker, a second circuit breaker, a third circuit breaker, a fourth circuit breaker, a first contactor, a second contactor, a third contactor, a fourth contactor and a fifth contactor;

[0012] The three phases A, B, and C of the AC distribution box or three-phase generator are connected to the input busbars of the three groups of modules of the combined switching power supply system after passing through the main contacts of the first circuit breaker and the first contactor in sequence. The input neutral lines of the three groups of modules of the combined switching power supply system are combined into one phase after passing through the main contacts of the fifth contactor and connected to the N phase of the AC distribution box or the three-phase generator;

[0013] The live wire and the neutral wire of the first single-phase generator are connected to the input bus and the input neutral wire of the first group of modules of the combined switching power supply system after passing through the main contacts of the second circuit breaker and the second contactor in sequence;

[0014] The live wire and the neutral wire of the second single-phase generator are connected to the input bus and the input neutral wire of the second group of modules of the combined switching power supply system after passing through the main contacts of the third circuit breaker and the third contactor in sequence;

[0015] The live wire and the neutral wire of the third single-phase generator are connected to the input bus and the input neutral wire of the first group of modules of the combined switching power supply system after passing through the main contacts of the fourth circuit breaker and the fourth contactor in sequence;

[0016] The first contactor and the fifth contactor are interlocked with the second contactor, the third contactor and the fourth contactor respectively; when any one of the second contactor, the third contactor and the fourth contactor is closed, the first contactor and the fifth contactor are disconnected, and when the first contactor is closed, the second contactor, the third contactor and the fourth contactor are disconnected.

[0017] Optionally, the first circuit breaker includes three branch switches, which are respectively connected to the three phases A, B, and C of the AC distribution box or the three-phase generator; the main contacts of the first contactor include three branch switches, which are respectively connected to the three branch switches of the first circuit breaker and the input busbars of the three groups of modules of the combined switching power supply system; the main contacts of the fifth contactor include three branch switches, which are respectively connected to the input neutral lines of the three groups of modules of the combined switching power supply system, and are combined and connected to the N phase of the AC distribution box or the three-phase generator.

[0018] Optionally, the second circuit breaker includes two branch switches, which are respectively connected to the live wire and the neutral wire of the first single-phase generator; the main contacts of the second contactor include two branch switches, which are respectively connected to the two branch switches of the second circuit breaker and the input bus and input neutral wire of the first group of modules of the combined switching power supply system; the third circuit breaker includes two branch switches, which are respectively connected to the live wire and the neutral wire of the second single-phase generator; the main contacts of the third contactor include two branch switches, which are respectively connected to the two branch switches of the third circuit breaker and the input bus and input neutral wire of the second group of modules of the combined switching power supply system; the fourth circuit breaker includes two branch switches, which are respectively connected to the live wire and the neutral wire of the third single-phase generator; the main contacts of the fourth contactor include two branch switches, which are respectively connected to the two branch switches of the fourth circuit breaker and the input bus and input neutral wire of the third group of modules of the combined switching power supply system.

[0019] Optionally, it further includes a first control button, a second control button, a third control button and a fourth control button;

[0020] After the normally open auxiliary contact of the first control button is connected in parallel with the normally open contact of the first contactor, it is connected in series with the normally closed auxiliary contact of the second control button, the first contactor coil, the fifth contactor coil, the normally closed contact of the second contactor, the normally closed contact of the third contactor and the normally closed contact of the fourth contactor to form an AC distribution box or a three-phase generator access control branch, which is connected between the A phase and the N phase of the AC distribution box or the three-phase generator;

[0021] After the normally open auxiliary contact of the second control button is connected in parallel with the normally open contact of the second contactor, it is connected in series with the normally closed auxiliary contact of the first control button, the second contactor coil and the first normally closed contact of the first contactor to form a first single-phase generator access control branch, which is connected between the live wire and the neutral wire of the first single-phase generator;

[0022] After the third control button is connected in parallel with the normally open contact of the third contactor, it is connected in series with the third contactor coil and the second normally closed contact of the first contactor to form a second single-phase generator access control branch, which is connected between the live wire and the neutral wire of the second single-phase generator;

[0023] After the fourth control button is connected in parallel with the normally open contact of the fourth contactor, it is connected in series with the third contactor coil and the third normally closed contact of the first contactor to form a third single-phase generator access control branch, which is connected between the live wire and the neutral wire of the third single-phase generator.

[0024] Optionally, it also includes a first power-on indicator light, a second power-on indicator light, a third power-on indicator light and a fourth power-on indicator light, the first power-on indicator light is connected in parallel to the AC distribution box or the three-phase generator access control branch, the second power-on indicator light is connected in parallel to the first single-phase generator access control branch, the third power-on indicator light is connected in parallel to the second single-phase generator access control branch, and the fourth power-on indicator light is connected in parallel to the third single-phase generator access control branch.

[0025] Optionally, it also includes a first power supply indicator light, a second power supply indicator light, a third power supply indicator light and a fourth power supply indicator light, the first power supply indicator light is connected in series to the AC distribution box or the three-phase generator access control branch, the second power supply indicator light is connected in series to the first single-phase generator access control branch, the third power supply indicator light is connected in series to the second single-phase generator access control branch, and the fourth power supply indicator light is connected in series to the third single-phase generator access control branch.

[0026] Optionally, an emergency button is also included, which is respectively connected in series with the AC distribution box or the three-phase generator access control branch, the first single-phase generator access control branch, the second single-phase generator access control branch and the third single-phase generator access control branch.

[0027] Optionally, it also includes multiple fuses, which are respectively arranged at both ends of the AC distribution box or the three-phase generator access control branch, the first single-phase generator access control branch, the second single-phase generator access control branch and the third single-phase generator access control branch.

[0028] According to the second aspect, the present invention proposes a base station generator parallel control system, including the base station generator parallel control circuit as described in the first aspect above, and also including a shell and a first interface, a second interface, a third interface, a fourth interface and a fifth interface. The base station generator parallel control circuit is arranged in the shell, the first interface is used to connect to an AC distribution box or a three-phase generator, the second interface is used to connect to a first single-phase generator, the third interface is used to connect to a second single-phase generator, the fourth interface is used to connect to a third single-phase generator, and the fifth interface is used to connect to the AC input end of a combined switching power supply system.

[0029] Optionally, the first interface, the second interface, the third interface and the fourth interface are all aviation plugs, and the fifth interface is fixedly connected by a cable.

[0030] The beneficial effects of the present invention are:

[0031] The parallel operation method of the present invention connects three single-phase generators to three groups of modules of the combined switching power supply system respectively. Different single-phase generators supply power to the switching power supply modules connected to different phases respectively. The neutral lines of each single-phase generator are physically isolated from each other, and there is no problem of zero-sequence current causing the generator to trip. There is no power conversion link in the parallel operation process, and there is no energy loss, and the conversion efficiency is high. The control circuit of the present invention can realize the functions of automatic switching of the neutral line, interlocking protection of AC power-generator power supply, etc., and a mechanical interlocking structure is designed on the basis of electrical interlocking to realize double insurance of interlocking protection, and the safety and automation degree are greatly improved. The present invention is provided with a signal indication circuit, a short-circuit protection circuit, a self-locking circuit, an emergency shutdown circuit, etc., and the degree of intelligence is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a main wiring diagram of the mains power supply control of a base station generator parallel control circuit embodiment of the present invention;

[0033] Figure 2 It is a main wiring diagram of a single-phase generator parallel power supply control in a base station generator parallel control circuit embodiment of the present invention;

[0034] Figure 3 It is a secondary control circuit diagram of an embodiment of a base station generator parallel control circuit of the present invention;

[0035] Figure 4 It is a schematic structural diagram of an embodiment of a base station generator parallel control system of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0037] The terms "first", "second" and "third" in this application are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number or order of the indicated technical features. All directional indications in the embodiments of this application (such as up, down, left, right, front, back...) are only used to explain the relative position relationship or movement between the components in a certain specific posture (as shown in the accompanying drawings); it should be noted that when a component is referred to as "fixed to", "set to", or "connected to" another component, it can be directly on the other component or there can be a central component. When a component is considered to be "connected" to another component, it can be directly connected to another component, or there may be one or more central components in between. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0038] like Figures 1 to 3 As shown, in order to solve the common problems in the prior art, the present invention proposes an embodiment of a base station generator parallel control circuit, and uses multiple AC contactors to design a control circuit, which can realize functions such as automatic switching of the neutral line, AC power-generator power supply electrical-mechanical dual interlocking protection, etc.

[0039] Specifically, see Figures 1 to 3 The present invention proposes a base station generator parallel control circuit embodiment, which is used to control an AC distribution box or a three-phase generator to supply power to a base station device through a combined switching power supply system, and to control three single-phase generators to supply power to the base station device through a combined switching power supply system as a backup. The base station generator parallel control circuit includes a first circuit breaker QF1, a second circuit breaker QF2, a third circuit breaker QF3, a fourth circuit breaker QF4, a first contactor KM1, a second contactor KM2, a third contactor KM3, a fourth contactor KM4, and a fifth contactor KM5.

[0040] See also Figure 1, the three phases A, B, and C of the AC distribution box or three-phase generator are connected to the input busbars U, V, and W of the three modules of the combined switching power supply system through the main contacts of the first circuit breaker QF1 and the first contactor KM1 in turn. The input neutral lines N1, N2, and N3 of the three modules of the combined switching power supply system are merged into one phase after passing through the main contacts of the fifth contactor KM5, and connected to the N phase of the AC distribution box or three-phase generator. When the first circuit breaker QF1, the first contactor KM1, and the fifth contactor KM5 are closed, the AC distribution box or the three-phase generator supplies power to the three modules of the combined switching power supply system. The first circuit breaker QF1 is used to control the opening and closing of the main power supply or the three-phase generator power supply, the first contactor KM1 is used for the interlocking protection of the three-phase live line, and the fifth contactor KM5 is used for the switching of the neutral line.

[0041] See also Figure 2 , the live wire l1 and the neutral wire n1 of the first single-phase generator G1 are connected to the input busbar U and the input neutral wire N1 of the first group of modules of the combined switching power supply system after passing through the main contacts of the second circuit breaker QF2 and the second contactor KM2 in sequence. When the second circuit breaker QF2 and the second contactor KM2 are closed, the first single-phase generator G1 supplies power to the first group of modules 1# / 4# / 7# of the combined switching power supply system. The second circuit breaker QF2 is used to control the opening and closing of the power supply of the first single-phase generator G1, and the second contactor KM2 is used for the interlocking protection of the live wire.

[0042] The live wire l2 and the neutral wire n2 of the second single-phase generator G2 are connected to the input busbar V and the input neutral wire N2 of the second group of modules of the combined switching power supply system after passing through the main contacts of the third circuit breaker QF3 and the third contactor KM3 in sequence. When the third circuit breaker QF3 and the third contactor KM3 are closed, the second single-phase generator G2 supplies power to the second group of modules 2# / 5# / 8# of the combined switching power supply system. The third circuit breaker QF3 is used to control the opening and closing of the power supply of the second single-phase generator G2, and the third contactor KM3 is used for the interlocking protection of the live wire.

[0043] The live wire l3 and the neutral wire n3 of the third single-phase generator G3 are connected to the input busbar W and the input neutral wire N3 of the first group of modules of the combined switching power supply system after passing through the main contacts of the fourth circuit breaker QF4 and the fourth contactor KM4 in sequence. When the fourth circuit breaker QF4 and the fourth contactor KM4 are closed, the third single-phase generator G3 supplies power to the third group of modules 3# / 6# / 9# of the combined switching power supply system. The fourth circuit breaker QF4 is used to control the opening and closing of the power supply of the third single-phase generator G3, and the fourth contactor KM4 is used for the interlocking protection of the live wire.

[0044] When powered by city electricity or a three-phase generator, the main contacts of the first circuit breaker (QF1), the first contactor (KM1) and the fifth contactor (KM5) are all closed, the main contacts of the second circuit breaker (QF2), the third circuit breaker (QF3), the fourth circuit breaker (QF4), the second contactor (KM2), the third contactor (KM3) and the fourth contactor (KM4) are all disconnected, and the three neutral lines on the load side are merged into one; when powered by a single-phase generator, the main contacts of the first circuit breaker (QF1), the first contactor (KM1) and the fifth contactor (KM5) are all disconnected, the circuit breaker and contactor main contacts of the line where the single-phase generator to be connected are closed, and the three neutral lines of the single-phase generator are physically isolated from each other.

[0045] The control circuit of the present invention connects three single-phase generators to three groups of modules of the combined switching power supply system respectively. Different single-phase generators supply power to the switching power supply modules connected to different phases respectively. The neutral lines of each single-phase generator are physically isolated from each other, and there is no problem of zero-sequence current causing the generator to trip.

[0046] When the mains is used for power supply or when the three-phase generator is used for power supply, the load side shares a neutral line. However, when 2 to 3 single-phase generators are connected in parallel, the neutral lines on the load side are isolated from each other. When different modes are used for power supply, the neutral line needs to be switched. Also, when the generator and the mains are powered at the same time, only one power supply can supply power to the rear-end load. Two power supplies cannot be used at the same time, otherwise electrical conflicts will cause safety accidents. The embodiment of the present invention provides the first contactor KM1 and the fifth contactor KM5, which are interlocked with the second contactor KM2, the third contactor KM3 and the fourth contactor KM4, respectively, to improve the safety of operation.

[0047] When any of the second contactor KM2, the third contactor KM3 and the fourth contactor KM4 is closed, the first contactor KM1 and the fifth contactor KM5 are both disconnected. At this time, as long as any of the three single-phase generators starts to supply power to the combined switching power supply system, the mains or three-phase generator cannot supply power to the combined switching power supply system.

[0048] When the first contactor KM1 is closed, the second contactor KM2, the third contactor KM3 and the fourth contactor KM4 are all disconnected. At this time, as long as the mains or the three-phase generator starts to supply power to the combined switching power supply system, the three single-phase generators cannot supply power to the combined switching power supply system.

[0049] The fifth contactor KM5, the first contactor KM1, the second contactor KM2 and the third contactor KM3 together form a zero line automatic switching circuit. When the mains or three-phase generator is powered, the fifth contactor KM5 is closed, and the three zero lines are combined into one. When the single-phase generator is powered, the fifth contactor KM5 is opened, and the three zero lines are isolated from each other.

[0050] In some embodiments, see Figure 1 The first circuit breaker QF1 includes three branch switches, which are respectively connected to the three phases A, B, and C of the AC distribution box or the three-phase generator; the main contacts of the first contactor KM1 include three branch switches, which are respectively connected to the three branch switches of the first circuit breaker QF1 and the input busbars U, V, and W of the three groups of modules of the combined switching power supply system; the main contacts of the fifth contactor KM5 include three branch switches, which are respectively connected to the input neutral lines N1, N2, and N3 of the three groups of modules of the combined switching power supply system, and are combined and connected to the N phase of the AC distribution box or the three-phase generator.

[0051] In some embodiments, see Figure 2 The second circuit breaker QF2 includes two branch switches, which are respectively connected to the live wire l1 and the neutral wire n1 of the first single-phase generator G1; the main contacts of the second contactor KM2 include two branch switches, which are respectively connected to the two branch switches of the second circuit breaker QF2 and the input bus U and the input neutral wire N1 of the first group of modules of the combined switching power supply system; the third circuit breaker QF3 includes two branch switches, which are respectively connected to the live wire l2 and the neutral wire n2 of the second single-phase generator G2; the main contacts of the third contactor KM3 include two branch switches, which are respectively connected to the two branch switches of the third circuit breaker QF3 and the input bus V and the input neutral wire N2 of the second group of modules of the combined switching power supply system; the fourth circuit breaker QF4 includes two branch switches, which are respectively connected to the live wire l3 and the neutral wire n3 of the third single-phase generator G3; the main contacts of the fourth contactor KM4 include two branch switches, which are respectively connected to the two branch switches of the fourth circuit breaker QF4 and the input bus W and the input neutral wire N3 of the third group of modules of the combined switching power supply system.

[0052] In some embodiments, see Figure 3 , further comprising a first control button S1, a second control button S2, a third control button S3 and a fourth control button S4.

[0053] Figure 3 It is a secondary control circuit diagram, which mainly realizes the output interlocking protection of AC power and generator, automatic switching of neutral line, energized indication of AC power and generator, power transmission indication of AC power and generator, manual power transmission operation of AC power or generator, self-locking retention of manual operation button, manual emergency cut-off operation and other functions through relay protection circuit.

[0054] After the normally open auxiliary contact S1-1 of the first control button S1 is connected in parallel with the normally open contact KM1-1 of the first contactor KM1, it is connected in series with the normally closed auxiliary contact S2-2 of the second control button S2, the first contactor KM1 coil, the fifth contactor KM5 coil, the normally closed contact KM2-2 of the second contactor KM2, the normally closed contact KM3-2 of the third contactor KM3 and the normally closed contact KM4-2 of the fourth contactor KM4 to form an AC distribution box or three-phase generator access control branch, which is connected between phase A 101 and phase N 102 of the AC distribution box or three-phase generator.

[0055] After the normally open auxiliary contact S2-1 of the second control button S2 is connected in parallel with the normally open contact KM2-1 of the second contactor KM2, it is connected in series with the normally closed auxiliary contact S1-2 of the first control button S1, the coil of the second contactor KM2 and the first normally closed contact KM1-2 of the first contactor KM1 to form a first single-phase generator access control branch, which is connected between the live wire 201 and the neutral wire 202 of the first single-phase generator G1.

[0056] After the third control button S3 is connected in parallel with the normally open contact KM3-1 of the third contactor KM3, it is connected in series with the third contactor KM3 coil and the second normally closed contact KM1-3 of the first contactor KM1 to form a second single-phase generator access control branch, which is connected between the live wire 301 and the neutral wire 302 of the second single-phase generator G2.

[0057] After the fourth control button S4 is connected in parallel with the normally open contact KM4-1 of the fourth contactor KM4, it is connected in series with the third contactor KM4 coil and the third normally closed contact KM1-4 of the first contactor KM1 to form a third single-phase generator access control branch, which is connected between the live wire 401 and the neutral wire 402 of the third single-phase generator G3.

[0058] The normally open auxiliary contact S1-1 of the first control button S1 is connected in parallel with the normally open contact KM1-1 of the first contactor KM1 to form a self-locking protection circuit. The first control button S1 is a manual control button for the mains or three-phase generator. The button is a composite button. When pressed, the normally open auxiliary contact S1-1 is closed and the normally closed auxiliary contact S1-2 is disconnected, forming a mechanical interlock with the power supply of the first single-phase generator G1. When the coil of the first contactor KM1 is energized, the main contact and the normally open contact KM1-1 of the first contactor KM1 are both closed to achieve self-locking, ensuring that when the first control button S1 is reset, the coil of the first contactor KM1 can continue to be energized through the normally open contact KM1-1, so that the circuit continues to operate; at this time, the first normally closed contact KM1-2, the second normally closed contact KM1-3 and the third normally closed contact KM1-4 of the first contactor KM1 are all disconnected, forming an electrical interlock with the power supply of the three single-phase generators.

[0059] The normally open auxiliary contact S2-1 of the second control button S2 is connected in parallel with the normally open contact KM2-1 of the second contactor KM2 to form a self-locking protection circuit. The second control button S2 is a manual start-up control button for the first unidirectional generator G1. This button is a composite button. When pressed, the normally open auxiliary contact S2-1 is closed and the normally closed auxiliary contact S2-2 is disconnected, forming a mechanical interlock with the power supply of the AC distribution box or the three-phase generator. When the coil of the second contactor KM2 is energized, the main contact and the normally open contact KM2-1 of the second contactor KM2 are both closed to achieve self-locking, ensuring that when the second control button S2 is reset, the coil of the second contactor KM2 can continue to be energized through the normally open contact KM2-1, so that the circuit continues to operate; at this time, the normally closed contact KM2-2 of the second contactor KM2 is disconnected, forming an electrical interlock with the power supply of the AC distribution box or the three-phase generator.

[0060] The third control button S3 is connected in parallel with the normally open contact KM3-1 of the third contactor KM3 to form a self-locking protection circuit. The third control button S3 is a manual start-up control button for the second unidirectional generator G2. When the coil of the third contactor KM3 is energized, the main contact and the normally open contact KM3-1 of the third contactor KM3 are both closed to achieve self-locking, ensuring that when the third control button S3 is reset, the coil of the third contactor KM3 can continue to be energized through the normally open contact KM3-1, so that the circuit continues to operate; at this time, the normally closed contact KM3-2 of the third contactor KM3 is disconnected, forming an electrical interlock with the power supply of the AC distribution box or the three-phase generator.

[0061] The fourth control button S4 is connected in parallel with the normally open contact KM4-1 of the fourth contactor KM4 to form a self-locking protection circuit. The fourth control button S4 is a manual start-up control button for the third unidirectional generator G3. When the coil of the fourth contactor KM4 is energized, the main contact and the normally open contact KM4-1 of the fourth contactor KM4 are both closed to achieve self-locking, ensuring that when the fourth control button S4 is reset, the coil of the fourth contactor KM4 can continue to be energized through the normally open contact KM4-1, so that the circuit continues to operate; at this time, the normally closed contact KM4-2 of the fourth contactor KM4 is disconnected, forming an electrical interlock with the power supply of the AC distribution box or the three-phase generator.

[0062] The coil of the fifth contactor KM5 is connected in series with the first control button S1, so that when the first control button S1 is turned on to the mains or the three-phase AC generator, the main contact of KM5 is closed and the three neutral lines are merged into one. The coil of the fifth contactor KM5 is connected in series with the normally closed auxiliary contacts KM2-2, KM3-3, and KM4-2, so that when other single-phase generators are connected in parallel, the coil of the fifth contactor KM5 loses power, the main contact is disconnected, and the neutral line is opened and separated into three. This realizes the automatic switching function of the neutral line.

[0063] In some embodiments, see Figure 3, also includes a first power indicator light HG1, a second power indicator light HG2, a third power indicator light HG3 and a fourth power indicator light HG4. The first power indicator light HG1 is connected in parallel to the AC distribution box or the three-phase generator access control branch to indicate whether the power supply of the AC distribution box or the three-phase generator is normal. When the power supply of the AC distribution box or the three-phase generator is normal, the first power indicator light HG1 is on. When the second power indicator light HG2 is connected in parallel to the first single-phase generator access control branch to indicate whether the power supply of the first single-phase generator G1 is normal. When the power supply of the first single-phase generator G1 is normal, the second power indicator light HG2 is on. When the third power indicator light HG3 is connected in parallel to the second single-phase generator access control branch to indicate whether the power supply of the second single-phase generator G2 is normal. When the power supply of the second single-phase generator G2 is normal, the third power indicator light HG3 is on. When the fourth power indicator light HG4 is connected in parallel to the third single-phase generator access control branch, it is used to indicate whether the power supply of the third single-phase generator G3 is normal. When the power supply of the third single-phase generator G3 is normal, the fourth power indicator light HG4 is on.

[0064] In some embodiments, see Figure 3 , and also includes a first power transmission indicator light HR1, a second power transmission indicator light HR2, a third power transmission indicator light HR3 and a fourth power transmission indicator light HR4. The first power transmission indicator light HR1 is connected in series to the AC distribution box or the three-phase generator access control branch, and is used to indicate the power transmission status of the AC distribution box or the three-phase generator. When the first contactor KM1 and the fifth contactor KM5 coils are energized and attracted, the AC distribution box or the three-phase generator starts to transmit power to the combined switching power supply system, and the first power transmission indicator light HR1 lights up. The second power transmission indicator light HR2 is connected in series to the first single-phase generator access control branch, and is used to indicate the power transmission status of the first single-phase generator G1. When the second contactor KM2 coil is energized and attracted, the first single-phase generator G1 starts to transmit power to the combined switching power supply system, and the second power transmission indicator light HR2 lights up. The third power transmission indicator HR3 is connected in series with the second single-phase generator access control branch to indicate the power transmission of the second single-phase generator G2. When the coil of the third contactor KM3 is energized and attracted, the second single-phase generator G2 starts to transmit power to the combined switching power supply system, and the third power transmission indicator HR3 lights up. The third power transmission indicator HR3 is connected in series with the second single-phase generator access control branch to indicate the power transmission of the second single-phase generator G2. When the coil of the third contactor KM3 is energized and attracted, the second single-phase generator G2 starts to transmit power to the combined switching power supply system, and the third power transmission indicator HR3 lights up. The fourth power transmission indicator HR4 is connected in series with the third single-phase generator access control branch to indicate the power transmission of the third single-phase generator G3. When the coil of the fourth contactor KM4 is energized and attracted, the third single-phase generator G3 starts to transmit power to the combined switching power supply system, and the fourth power transmission indicator HR4 lights up.

[0065] In some embodiments, an emergency button SB1 is also included, and the emergency button SB1 is connected in series with the AC distribution box or the three-phase generator access control branch, the first single-phase generator access control branch, the second single-phase generator access control branch, and the third single-phase generator access control branch. When an emergency occurs, the emergency button SB1 can be manually pressed, and the coils of the first contactor KM1, the second contactor KM2, the third contactor KM3, the fourth contactor KM4, and the fifth contactor KM5 are all powered off, the main contacts are all disconnected, and all external power supplies of the combined switching power supply are cut off.

[0066] In some embodiments, see Figure 3 , and also includes multiple fuses F1~F8, which are respectively arranged at both ends of the AC distribution box or the three-phase generator access control branch, the first single-phase generator access control branch, the second single-phase generator access control branch and the third single-phase generator access control branch, for short-circuit current protection of the control circuit to ensure that the external short-circuit current will not break down the electronic components in the control circuit.

[0067] The working process of a base station generator parallel control circuit embodiment proposed by the present invention is as follows:

[0068] 1. When the mains or three-phase generator is supplying power: first close the first circuit breaker QF1, the first energized indicator light HG1 turns green, indicating that the mains or three-phase generator is supplying power normally; manually press the first control button S1, the normally open auxiliary contact S1-1 of the first control button S1 is closed, and the coils of the first contactor KM1 and the fifth contactor KM5 are energized; the main contacts of the first contactor KM1 and the fifth contactor KM5 are closed, and the live wire of the mains or three-phase generator is connected to the neutral wire that is combined into one; the first power supply indicator light HR1 turns red, indicating that the mains or three-phase generator is supplying power normally; at the same time, the normally closed contact S1-2 of the first control button S1 is disconnected, and the mechanical interlocking of the second contactor KM2 is realized, so that the main contact of the second contactor KM2 is The first contactor KM1 is disconnected, and the normally open auxiliary contact KM1-1 of the first contactor KM1 is closed; the three normally closed auxiliary contacts KM1-2, KM1-3, and KM1-4 of the first contactor KM1 are disconnected, and the second contactor KM2, the third contactor KM3, and the fourth contactor KM4 are electrically interlocked, so that the second control button S2, the third control button S3, and the fourth control button S4 lose their functions; the first control button S1 is reset after the key is released; the normally open auxiliary contact S1-1 of the first control button is disconnected, and the normally closed auxiliary contact S1-2 is closed, but since the normally open auxiliary contact KM1-1 of the first contactor KM1 is closed, the first contactor KM1 and the second contactor KM5 are continuously energized, realizing the self-locking function of the first control button S1.

[0069] 2. When the first single-phase generator G1 supplies power: first close the second circuit breaker QF2, the second power indicator HG2 lights up green, indicating that the first single-phase generator G1 is supplying power normally; manually press the second control button S2, the normally open auxiliary contact S2-1 of the second control button S2 is closed, and the normally closed contact S2-2 of the second control button S2 is disconnected, and the first contactor KM1 and the fifth contactor KM5 are mechanically interlocked; the main contacts of the first contactor KM1 and the fifth contactor KM5 are disconnected, the main power supply is disconnected, and the neutral line is automatically separated into 3 lines; at the same time, the coil of the second contactor KM2 is energized; the main contact of the fifth contactor KM2 is closed, and the first single-phase Generator G1 supplies power; the second power supply indicator HR2 lights up in red, indicating that the first single-phase generator G1 is supplying power normally; the normally closed auxiliary contact KM2-2 of the second contactor KM2 is disconnected, realizing electrical interlocking of the first contactor KM1 and the fifth contactor KM5, rendering the first control button S1 ineffective; after releasing the second control button S2, it resets, the normally open auxiliary contact S2-1 of the second control button is disconnected, and the normally closed contact S2-2 of the second control button S2 is closed, but since the normally open contact KM2-1 of the second contactor KM2 is closed, the second contactor KM2 continues to be energized, realizing the self-locking function of the second control button S2.

[0070] 3. When the second single-phase generator G2 supplies power: close the third circuit breaker QF3, the third energized indicator light HG3 turns green, indicating that the second single-phase generator G2 is supplying power normally; manually press the third control button S3, the coil of the third contactor KM3 is energized, the main contact of the third contactor KM3 is closed, and the second single-phase generator G2 is supplying power; the third power supply indicator light HR3 turns red, indicating that the second single-phase generator G2 is supplying power normally; at the same time, the normally open auxiliary contact KM3-1 of the third contactor KM3 is closed, and the third control button S3 is self-locked, keeping the coil of the third contactor KM3 energized; the normally closed auxiliary contact KM3-2 of the third contactor KM3 is disconnected, and the first contactor KM1 and the fifth contactor KM5 are electrically interlocked, making the first control button S1 ineffective.

[0071] 4. When the third single-phase generator G3 supplies power: close the fourth circuit breaker QF4, the fourth energized indicator light HG4 turns green, indicating that the third single-phase generator G3 is supplying power normally; manually press the fourth control button S4, the coil of the fourth contactor KM4 is energized, the main contact of the fourth contactor KM4 is closed, and the third single-phase generator G3 is supplying power; the fourth power supply indicator light HR4 turns red, indicating that the third single-phase generator G3 is supplying power normally; at the same time, the normally open auxiliary contact KM4-1 of the fourth contactor KM4 is closed, and the fourth control button S4 is self-locked, keeping the coil of the fourth contactor KM4 energized; the normally closed auxiliary contact KM4-2 of the fourth contactor KM4 is disconnected, interlocking the first contactor KM1 and the fifth contactor KM5, making the first control button S1 ineffective.

[0072] See also Figure 4 The present invention proposes an embodiment of a base station generator parallel control system, including the base station generator parallel control circuit in the above-mentioned embodiments, and also including a housing and a first interface J1, a second interface J2, a third interface J3, a fourth interface J4 and a fifth interface J5. The base station generator parallel control circuit is arranged in the housing, the first interface J1 is used to connect to an AC distribution box or a three-phase generator, the second interface J2 is used to connect to a first single-phase generator G1, the third interface J3 is used to connect to a second single-phase generator G2, the fourth interface J4 is used to connect to a third single-phase generator G3, and the fifth interface J5 is connected to an AC input end of a combined switching power supply system.

[0073] The present invention proposes a base station generator parallel control system embodiment access method as follows:

[0074] 1. When the AC power is supplied, the first interface J1 is connected to the output terminal of the AC distribution box of the base station, and the AC power is supplied to the switching power supply through the device.

[0075] 2. After the city power outage, when a three-phase generator is needed for emergency power generation, the cable terminal of the AC distribution box can be disconnected from the first interface J1, and the three-phase generator can be quickly connected to the first interface J1, and the three-phase generator can be used to supply power to the switching power supply through this device.

[0076] After the mains power outage, when a single-phase generator is needed to generate electricity alone or in parallel, there is no need to disconnect the first interface J1. The single-phase generator can be quickly connected to the second interface J2, the third interface J3 and the fourth interface J4 as needed. Through this device, a single or multiple generators can supply power to the combined switching power supply. After the power generation is completed, the mains power supply can be restored first, and then the second interface J2, the third interface J3 and the fourth interface J4 can be unplugged. No other steps are required, and the operation is convenient and flexible.

[0077] In some embodiments, the first interface J1, the second interface J2, the third interface J3 and the fourth interface J4 are all aviation plugs, which can achieve fast and reliable access. The fifth interface J5 is fixedly connected by a cable.

[0078] The parallel operation method of the present invention connects three single-phase generators to three groups of modules of the combined switching power supply system respectively. Different single-phase generators supply power to the switching power supply modules connected to different phases respectively. The neutral lines of each single-phase generator are physically isolated from each other, and there is no problem of zero-sequence current causing the generator to trip. There is no power conversion link in the parallel operation process, and there is no energy loss, and the conversion efficiency is high. The control circuit of the present invention can realize the functions of automatic switching of the neutral line, interlocking protection of AC power-generator power supply, etc., and a mechanical interlocking structure is designed on the basis of electrical interlocking to realize double insurance of interlocking protection, and the safety and automation degree are greatly improved. The present invention is provided with a signal indication circuit, a short-circuit protection circuit, a self-locking circuit, an emergency shutdown circuit, etc., and the degree of intelligence is higher.

[0079] The present invention is not limited to the above-mentioned optional implementation modes. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that fall within the scope defined by the claims of the present invention fall within the protection scope of the present invention.

Claims

1. A base station generator parallel control circuit, used to control an AC distribution box or a three-phase generator to supply power through a combined switching power supply system, and to control three single-phase generators to supply power through a combined switching power supply system as a backup; characterized in that: It includes a first circuit breaker (QF1), a second circuit breaker (QF2), a third circuit breaker (QF3), a fourth circuit breaker (QF4), a first contactor (KM1), a second contactor (KM2), a third contactor (KM3), a fourth contactor (KM4) and a fifth contactor (KM5); The three phases A, B, and C of the AC distribution box or the three-phase generator are connected to the input busbars (U, V, and W) of the three groups of modules of the combined switching power supply system after passing through the main contacts of the first circuit breaker (QF1) and the first contactor (KM1) in sequence, and the input neutral lines (N1, N2, and N3) of the three groups of modules of the combined switching power supply system are combined into one phase after passing through the main contacts of the fifth contactor (KM5) and connected to the N phase of the AC distribution box or the three-phase generator; The live wire (l1) and the neutral wire (n1) of the first single-phase generator (G1) are connected to the input busbar (U) and the input neutral wire (N1) of the first group of modules of the combined switching power supply system after passing through the main contacts of the second circuit breaker (QF2) and the second contactor (KM2) in sequence; The live wire (l2) and the neutral wire (n2) of the second single-phase generator (G2) are connected to the input bus (V) and the input neutral wire (N2) of the second group of modules of the combined switching power supply system after passing through the main contacts of the third circuit breaker (QF3) and the third contactor (KM3) in sequence; The live wire (l3) and the neutral wire (n3) of the third single-phase generator (G3) are connected to the input bus (W) and the input neutral wire (N3) of the first group of modules of the combined switching power supply system after passing through the main contacts of the fourth circuit breaker (QF4) and the fourth contactor (KM4) in sequence; The first contactor (KM1) and the fifth contactor (KM5) are interlocked with the second contactor (KM2), the third contactor (KM3) and the fourth contactor (KM4) respectively; when any of the second contactor (KM2), the third contactor (KM3) and the fourth contactor (KM4) is closed, the first contactor (KM1) and the fifth contactor (KM5) are disconnected; when the first contactor (KM1) is closed, the second contactor (KM2), the third contactor (KM3) and the fourth contactor (KM4) are disconnected.

2. A base station generator parallel control circuit according to claim 1, characterized in that: The first circuit breaker (QF1) includes three branch switches, which are respectively connected to the three phases A, B, and C of the AC distribution box or the three-phase generator; the main contacts of the first contactor (KM1) include three branch switches, which are respectively connected to the three branch switches of the first circuit breaker (QF1) and the input busbars (U, V, and W) of the three groups of modules of the combined switching power supply system; the main contacts of the fifth contactor (KM5) include three branch switches, which are respectively connected to the input neutral lines (N1, N2, and N3) of the three groups of modules of the combined switching power supply system, and are combined and connected to the N phase of the AC distribution box or the three-phase generator.

3. A base station generator parallel control circuit according to claim 1, characterized in that: The second circuit breaker (QF2) includes two branch switches, which are respectively connected to the live wire (l1) and the neutral wire (n1) of the first single-phase generator (G1); the main contact of the second contactor (KM2) includes two branch switches, which are respectively connected to the two branch switches of the second circuit breaker (QF2) and the input busbar (U) and the input neutral wire (N1) of the first group of modules of the combined switching power supply system; the third circuit breaker (QF3) includes two branch switches, which are respectively connected to the live wire (l2) and the neutral wire (n2) of the second single-phase generator (G2); the main contact of the third contactor (KM3) The point includes two branch switches, which are respectively connected to the two branch switches of the third circuit breaker (QF3) and the input bus (V) and the input neutral line (N2) of the second group of modules of the combined switching power supply system; the fourth circuit breaker (QF4) includes two branch switches, which are respectively connected to the live line (l3) and the neutral line (n3) of the third single-phase generator (G3); the main contact of the fourth contactor (KM4) includes two branch switches, which are respectively connected to the two branch switches of the fourth circuit breaker (QF4) and the input bus (W) and the input neutral line (N3) of the third group of modules of the combined switching power supply system.

4. A base station generator parallel control circuit according to claim 1, characterized in that: Also includes a first control button (S1), a second control button (S2), a third control button (S3) and a fourth control button (S4); After the normally open auxiliary contact (S1-1) of the first control button (S1) is connected in parallel with the normally open contact (KM1-1) of the first contactor (KM1), it is connected in series with the normally closed auxiliary contact (S2-2) of the second control button (S2), the coil of the first contactor (KM1), the coil of the fifth contactor (KM5), the normally closed contact (KM2-2) of the second contactor (KM2), the normally closed contact (KM3-2) of the third contactor (KM3) and the normally closed contact (KM4-2) of the fourth contactor (KM4) to form an AC distribution box or a three-phase generator access control branch, which is connected between the A phase (101) and the N phase (102) of the AC distribution box or the three-phase generator; After the normally open auxiliary contact (S2-1) of the second control button (S2) is connected in parallel with the normally open contact (KM2-1) of the second contactor (KM2), it is connected in series with the normally closed auxiliary contact (S1-2) of the first control button (S1), the coil of the second contactor (KM2) and the first normally closed contact (KM1-2) of the first contactor (KM1) to form a first single-phase generator access control branch, which is connected between the live wire (201) and the neutral wire (202) of the first single-phase generator (G1); After the third control button (S3) is connected in parallel with the normally open contact (KM3-1) of the third contactor (KM3), it is connected in series with the coil of the third contactor (KM3) and the second normally closed contact (KM1-3) of the first contactor (KM1) to form a second single-phase generator access control branch, which is connected between the live wire (301) and the neutral wire (302) of the second single-phase generator (G2); After the fourth control button (S4) is connected in parallel with the normally open contact (KM4-1) of the fourth contactor (KM4), it is connected in series with the coil of the third contactor (KM4) and the third normally closed contact (KM1-4) of the first contactor (KM1) to form a third single-phase generator access control branch, which is connected between the live wire (401) and the neutral wire (402) of the third single-phase generator (G3).

5. A base station generator parallel control circuit according to claim 4, characterized in that: It also includes a first power-on indicator light (HG1), a second power-on indicator light (HG2), a third power-on indicator light (HG3) and a fourth power-on indicator light (HG4), wherein the first power-on indicator light (HG1) is connected in parallel to the AC distribution box or the three-phase generator access control branch, the second power-on indicator light (HG2) is connected in parallel to the first single-phase generator access control branch, the third power-on indicator light (HG3) is connected in parallel to the second single-phase generator access control branch, and the fourth power-on indicator light (HG4) is connected in parallel to the third single-phase generator access control branch.

6. A base station generator parallel control circuit according to claim 4, characterized in that: It also includes a first power supply indicator light (HR1), a second power supply indicator light (HR2), a third power supply indicator light (HR3) and a fourth power supply indicator light (HR4), wherein the first power supply indicator light (HR1) is connected in series to the AC distribution box or the three-phase generator access control branch, the second power supply indicator light (HR2) is connected in series to the first single-phase generator access control branch, the third power supply indicator light (HR3) is connected in series to the second single-phase generator access control branch, and the fourth power supply indicator light (HR4) is connected in series to the third single-phase generator access control branch.

7. A base station generator parallel control circuit according to claim 4, characterized in that: It also includes an emergency button (SB1), which is respectively connected in series with the AC distribution box or the three-phase generator access control branch, the first single-phase generator access control branch, the second single-phase generator access control branch and the third single-phase generator access control branch.

8. A base station generator parallel control circuit according to claim 4, characterized in that: It also includes a plurality of fuses (F1), which are respectively arranged at the two ends of the AC distribution box or the three-phase generator access control branch, the first single-phase generator access control branch, the second single-phase generator access control branch and the third single-phase generator access control branch.

9. A base station generator parallel control system, comprising a base station generator parallel control circuit according to any one of claims 1 to 6, characterized in that: The invention also comprises a housing and a first interface (J1), a second interface (J2), a third interface (J3), a fourth interface (J4) and a fifth interface (J5); the base station generator parallel control circuit is arranged in the housing; the first interface (J1) is used to connect to an AC distribution box or a three-phase generator; the second interface (J2) is used to connect to a first single-phase generator (G1); the third interface (J3) is used to connect to a second single-phase generator (G2); the fourth interface (J4) is used to connect to a third single-phase generator (G3); and the fifth interface (J5) is used to connect to an AC input end of a combined switching power supply system.

10. A base station generator parallel control system according to claim 9, characterized in that: The first interface (J1), the second interface (J2), the third interface (J3) and the fourth interface (J4) are all aviation plugs, and the fifth interface (J5) is fixedly connected via a cable.

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