Preparation method of high-power direct-current power supply for airplane ground starting

Abstract

The invention relates to the technical field of aviation power supplies, in particular to a preparation method of a high-power direct-current power supply for airplane ground starting, which comprises the steps of main loop design and control loop design. Continuous large starting current can be provided for an aircraft. During specific use, 380V three-phase alternating current is connected, when input voltage changes or loads change, output voltage can be automatically adjusted and stabilized, specifically, the power supply manufactured through the method outputs a specific voltage value + 28.5 V through the design of a three-phase saturable reactor, the design of a main transformer and the design of a control loop, continuous work can be achieved, the power reaches 15KW, and the instantaneous maximum power is 30KW; the device can be used for ground starting and ground power-on inspection of the airplane; meanwhile, the high-power direct-current stabilized power supply can be used in other places needing high-power direct-current stabilized power supplies.

Description

Technical Field

[0001] The invention relates to the technical field of aviation power supply, and in particular to a method for preparing a high-power direct current power supply for ground starting of an aircraft. Background Art

[0002] The starting power supply is a DC power supply specially used for starting, lighting, ignition and power supply of vehicles, ships and aircraft. The existing starting power supply (such as patent number: CN203660616U, patent name: A high-power engine starting power supply device) is realized by a capacitor module. Although the structure is relatively simple, it has the following disadvantages in specific use: 1. The existing starting power supply needs to be charged multiple times when used, and one charge cannot work for a long time and multiple times; 2. The existing starting power supply cannot continuously provide a high power of more than 15KW, and cannot meet the specific requirements of aircraft ground starting and testing. Summary of the invention

[0003] The purpose of the present invention is to provide a method for preparing a high-power DC power supply for ground starting of an aircraft. The high-power power supply prepared by the power supply preparation method solves the problem of continuous operation of the high-power DC power supply, has a specific voltage value of +28.5V output, a power of 15KW, can work continuously for more than 8 hours, and an instantaneous power (10s) of 30KW; and is provided with a voltage stabilizing control circuit, which can automatically adjust the stable output voltage when the input voltage (AC380V) or the load changes.

[0004] In order to achieve the above object, the present invention adopts the following technical solution: A method for preparing a high-power DC power supply for ground starting of an aircraft, including main circuit design and control circuit design; The main circuit is designed as follows: three-phase 380V AC is used as input, and is sequentially passed through an air automatic circuit breaker, an AC contactor, and a three-phase saturated reactor, and then added to the main transformer. After being stepped down by the main transformer, it is connected to a balancing reactor, and then passes through a filter circuit composed of LC to become a stable DC output; The control loop is designed as follows: The control circuit includes a proportional operation circuit, a phase angle control circuit, a unidirectional bridge rectifier circuit and an overvoltage protection circuit; The proportional operation circuit is composed of an operator and a resistor, and is used to process the sampling signal. The processed signal is proportional to the sampling signal and is connected to the phase angle control circuit through the power circuit as its control signal. The phase angle control circuit is composed of the phase angle control chip TCA785 and related discrete resistor and capacitor components; it uses the voltage input by the proportional operation circuit and the AC synchronization signal as reference. If the voltage increases, the conduction angle of the control signal output by it decreases; if the voltage decreases, the conduction angle of the control signal output by it increases. The conduction angle is based on the synchronization signal introduced from the AC380V power supply input terminal through the transformer as a reference; The unidirectional bridge rectifier circuit is composed of rectifier diodes, current limiting resistors, thyristors and other devices, and is equipped with thyristor RC protection circuit and freewheeling circuit; the current limiting resistor is connected in parallel with the AC contactor, and the AC contactor is controlled to close when necessary, which can greatly increase the DC current in the control coil of the three-phase saturated reactor; the main function of the unidirectional bridge rectifier circuit is to change the DC current in the control coil of the three-phase saturated reactor by changing the conduction angle of the thyristor; The overvoltage protection circuit is composed of a voltage comparator, a power tube, a resistor, a capacitor, a light-emitting diode, a delay circuit, and a power drive circuit; the overvoltage protection circuit makes a real-time judgment on the power supply output voltage. When the voltage exceeds the judgment threshold, the voltage comparator outputs a high level, and the threshold voltage indicator light is on. At this time, the delay circuit composed of a single junction transistor continuously judges the high level output by the comparator. If the high level lasts for 4 to 6 seconds, the single junction transistor is turned on, and the system power disconnect indicator light is on. At the same time, the external relay is controlled to disconnect through the thyristor power drive circuit, thereby controlling the contactor control combination to disconnect and cut off the power input.

[0005] Furthermore, the DC output of the main circuit is used as a sampling signal. After passing through the proportional operation circuit, it is connected to the emitter follower. After power amplification, it passes through the phase angle control circuit (two phases of the 380V AC power in the main circuit are taken, and after being stepped down by the transformer, they are used as the synchronization signal of the phase angle control circuit). The input generates a phase angle control signal, which is isolated and connected to the unidirectional bridge rectifier circuit to control the DC current of the control coil in the three-phase saturated reactor.

[0006] Furthermore, when the input three-phase 380V AC power or load changes, the DC voltage output by the main circuit also changes. For example, when the output voltage increases, the control circuit sampling voltage increases, causing the phase angle control signal to change, and the phase shift angle to increase, thereby reducing the conduction angle of the thyristor in the unidirectional bridge rectifier circuit, reducing the DC current of the three-phase saturated reactor control coil, and increasing the inductance of the three AC working coils of the three-phase saturated reactor. The primary winding voltage of the main transformer decreases, which reduces the output DC voltage accordingly, so that the output DC voltage is basically maintained at the original level, thereby achieving the purpose of automatic control.

[0007] Furthermore, the DC output of the main circuit is selected as the sampling signal, and connected to the delay circuit after passing through the voltage comparator. When the DC output of the main circuit exceeds the set overvoltage protection value, the delay circuit starts timing. After reaching the specified time, the control signal is output. After passing through the power drive circuit, the control relay and contactor turn on the control module, disconnecting the power input to achieve the purpose of overvoltage protection.

[0008] The beneficial effects of the present invention are as follows: the power supply prepared by the method for preparing a high-power DC power supply for ground starting of an aircraft provided by the present invention can provide a continuous and large starting current for the aircraft. When used specifically, a 380V three-phase AC power supply is connected, and when the input voltage changes or the load changes, the output voltage can be automatically adjusted to stabilize. Specifically, the power supply prepared by the method is designed through a three-phase saturated reactor, a main transformer design, and a control circuit design, and has a specific voltage value of +28.5V output, can work continuously, and has a power of 15KW, with an instantaneous maximum power (lasting 10s) of 30KW; it can be used for ground starting and ground power-on inspection of aircraft; at the same time, it can also be used in other places where a high-power DC stabilized power supply is required. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is an overall design block diagram of the method for preparing a high-power power supply for ground starting of an aircraft according to the present invention; Figure 2 It is an electrical principle diagram of a three-phase saturated reactor in a method for preparing a high-power power supply for ground starting of an aircraft according to the present invention; Figure 3 It is the electrical principle diagram of the main transformer in the method for preparing a high-power power supply for ground starting of an aircraft of the present invention; DETAILED DESCRIPTION

[0010] Specific embodiment 1: The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. It should be noted that: in the present invention, if there is no special description, all the implementation methods and preferred implementation methods mentioned herein can be combined with each other to form a new technical solution. In the present invention, if there is no special description, all the technical features and preferred features mentioned herein can be combined with each other to form a new technical solution. The "scope" disclosed in the present invention can be in the form of a lower limit and an upper limit, which can be one or more lower limits, and one or more upper limits, respectively.

[0011] As the instruction manual Figure 1As shown, in order to solve the problem that the existing starting power supply needs to be charged, cannot work for a long time and multiple times after one charge, and cannot continuously output high power, and thus cannot meet the specific use requirements of aircraft ground starting, the present invention designs and provides a method for preparing a high-power power supply for aircraft ground starting. The method for preparing a high-power DC power supply for aircraft ground starting mainly includes the main circuit design and the control circuit design. The three-phase 380V AC is used as input, and is sequentially added to the main transformer through the air automatic circuit breaker, AC contactor, and three-phase saturated reactor. After the main transformer steps down the voltage, it is connected to the balancing reactor, and then becomes a stable DC output after passing through the filter circuit composed of LC. The main circuit is the power circuit of the power supply, and the dynamically controllable device is a three-phase saturated reactor. Under the action of the control circuit, it outputs a constant DC regulated voltage. At the same time, according to the load condition, the control circuit adjusts the size of the inductance of the three-phase saturated reactor. Its three AC working coils are respectively wound on three silicon steel sheets, and a common DC control coil is wound outside the three working coils. The magnetic permeability of the silicon steel sheet is changed by controlling the current of the DC coil. If the DC current in the DC control coil increases, the inductance of the three AC working coils decreases; conversely, when the DC current decreases, the inductance of the three AC working coils increases. In this way, changing the DC current in the DC control coil can adjust the input voltage of the main transformer, thereby adjusting the output DC voltage. If there is an overvoltage at the output, the system will automatically cut off the power supply to protect the load under the control condition of the overvoltage circuit. The core of the present invention lies in the design of the three-phase saturated reactor, the design of the main transformer and the design of the control loop. The design process of the above three is explained below.

[0012] The design of the above three-phase saturated reactor is as follows: The schematic diagram of the three-phase saturated reactor is as attached to the instruction manual. Figure 2 As shown. Among them, A—A', B—B', C—C' are working coil windings, A, B, C lead wires are used to connect to the 380V AC power through the AC contactor, A', B', C' lead wires are used to connect to the main transformer; H—H' is the control coil winding, and the lead wires are used to connect to the unidirectional bridge rectifier circuit in the control loop;

[0013] The manufacturing method of the three-phase saturated reactor is as follows: First, wind the working coil windings Ⅰ, Ⅱ, and Ⅲ according to the above table, with the number of turns in each layer being equal. Use a special clamp to connect the three skeletons with the working coil windings, and then wind the control coil winding Ⅳ and the short-circuit coil winding Ⅴ; The silicon steel sheets (cold-rolled Z10) used are sprayed with an insulating layer on the surface, with a thickness of 0.35mm. There are 180 silicon steel sheets, each with 5 sheets in a group, with the bar core and the E-type core stacked crosswise. The core is painted with gray magnetic paint. The lead wire part of each winding is covered with an insulating sleeve; Test: The insulation resistance between coil windings and between coil windings and the iron core is greater than 200MΩ, the insulation resistance is greater than 20MΩ in hot state, and can withstand AC 2000V for 1 minute; Connect the three working coil windings of the saturated reactor into a Y-shape, gradually increase the input voltage of the saturated reactor, and the no-load current of each phase should be basically equal at the same voltage; Gradually increase the input voltage. When the phase current of the saturated reactor reaches 15A, its input voltage should be 135-150V. The no-load current at different voltages should meet the requirements in the following table:

[0014] The design of the main transformer is as follows: The schematic diagram of the main transformer is attached to the instruction manual. Figure 3 As shown, the main transformer is divided into a primary winding and a secondary winding, wherein the primary winding includes three groups, A-A', B-B', and C-C'. The A, B, and C lead wires are used to connect to the three-phase saturated reactor, and the C and D lead wires are used to connect to the unidirectional bridge rectifier circuit in the control loop; The secondary winding is divided into 4 groups, and every 2 groups form 1 circuit, which are connected to the balancing reactor and the rectifier circuit in 2 circuits respectively; Primary Winding Secondary Winding

[0016] Wind the primary and secondary windings according to the table above; Use δ=0.35 cold-rolled silicon steel sheet, spray the surface with insulation treatment layer, the thickness of the insulation layer is 0.35mm, 10 sheets are stacked crosswise in a group, and the total number of sheets per phase is 340; the iron core is painted with gray enamel; Test: The insulation resistance between the primary and secondary and the iron core, and between the primary and secondary is greater than 200MΩ, the insulation resistance in the hot state is greater than 20MΩ, and can withstand AC 2000V for 1 minute; the insulation resistance between the secondary is greater than 20MΩ, and can withstand AC 500V for 1 minute; Phases A, B, and C are connected to a 50Hz three-phase AC power supply, and the voltage is gradually increased using a three-phase autotransformer. When the voltage is 280V, the no-load current is less than 5.5A; When the primary voltage of each phase of A, B, and C is 200V, the secondary voltage is 18.3±0.5V; the voltage difference between each secondary winding should not be greater than 0.5V; the voltage between the B phase coils D and C (ie B, D) is 45.5±4V.

[0017] The control loop is designed as follows: As the instruction manual Figure 1 As shown, the control circuit mainly consists of a proportional operation circuit, a phase angle control circuit, a unidirectional bridge rectifier circuit and an overvoltage protection circuit; The proportional operation circuit is composed of an operator and a resistor, and is used to process the sampling signal. The processed signal is proportional to the sampling signal and is connected to the phase angle control circuit through the power circuit as its control signal. The phase angle control circuit is composed of the phase angle control chip TCA785 and related discrete resistor and capacitor components. It uses the voltage input by the proportional operation circuit and the AC synchronization signal as a reference. If the voltage increases, the conduction angle of the control signal output by it decreases. If the voltage decreases, the conduction angle of the control signal output by it increases. The conduction angle is based on the synchronization signal introduced from the AC380V power supply line end through the transformer as a reference.

[0018] The unidirectional bridge rectifier circuit is composed of rectifier diodes, current limiting resistors, thyristors and other devices, and is equipped with thyristor RC protection circuit and freewheeling circuit; the current limiting resistor is connected in parallel with the AC contactor, and the AC contactor is controlled to close when necessary, which can greatly increase the DC current in the control coil of the three-phase saturated reactor. The main function of the unidirectional bridge rectifier circuit is to change the DC current in the control coil of the three-phase saturated reactor by changing the conduction angle of the thyristor; The overvoltage protection circuit is mainly composed of a voltage comparator, a power tube, a resistor, a capacitor, a light-emitting diode, a delay circuit, and a power drive circuit. The overvoltage protection circuit makes a real-time judgment on the power supply output voltage. When the voltage exceeds the judgment threshold, the voltage comparator outputs a high level, and the threshold voltage indicator lights up. At this time, the delay circuit composed of a single junction transistor continuously judges the high level output by the comparator. If the high level lasts for 4 to 6 seconds, the single junction transistor is turned on, and the system power disconnect indicator lights up. At the same time, the thyristor power drive circuit controls the external relay to disconnect, thereby controlling the contactor control combination to disconnect and cut off the power input.

[0019] The working process of the power supply prepared by the method for preparing a high-power power supply for ground starting of an aircraft of the present invention is as follows: The three-phase 380V AC power is input, and is added to the main transformer through the air automatic circuit breaker, AC contactor, and three-phase saturated reactor in sequence. After the main transformer steps down the voltage, it is connected to the balancing reactor. After passing through the filter circuit composed of LC, it becomes a stable DC output.

[0020] The output voltage of the power supply is regulated by changing the current of the control coil in the three-phase saturated reactor. The three AC working coils of the three-phase saturated reactor are wound on three cores respectively, and a common DC control coil is wound outside the three working coils. When the DC current in the DC control coil increases and the core is saturated, the inductance of the three AC working coils decreases; conversely, when the DC current decreases, the inductance of the three AC working coils increases. In this way, changing the DC current in the DC control coil can adjust the input voltage of the main transformer, thereby adjusting the output DC voltage; The control circuit samples the output voltage of the power supply, and after sampling, it enters the phase angle control circuit after the proportional operation circuit, controls the phase shift angle and the conduction angle of the thyristor, and changes the DC current in the DC control coil of the saturated reactor to achieve the purpose of automatically maintaining the stability of the output voltage. For example, when the input three-phase AC voltage increases, the DC voltage output after rectification also increases. At this time, the sampling voltage increases, the phase shift voltage in the thyristor phase shift circuit increases, and the phase shift angle of the trigger pulse increases, which reduces the conduction angle of the thyristor, reduces the DC current in the DC control coil of the saturated reactor, increases the inductance of the three AC working coils of the three-phase saturated reactor, reduces the primary winding voltage of the main transformer, and reduces the output DC voltage accordingly, so that the output DC voltage is basically maintained at the original level.

[0021] In addition, a current limiting resistor is connected in series with the control coil of the three-phase saturated reactor. When the load requires a larger current, the control circuit controls the AC contactor to short-circuit the current limiting resistor, so that a larger current flows through the control coil of the three-phase saturated reactor, thereby obtaining a larger load current, with a power of up to 30KW.

[0022] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a high-power DC power supply for ground starting of an aircraft, characterized in that: Including main circuit design and control circuit design; The main circuit is designed as follows: three-phase 380V AC is used as input, and is sequentially passed through an air automatic circuit breaker, an AC contactor, and a three-phase saturated reactor, and then added to the main transformer. After being stepped down by the main transformer, it is connected to a balancing reactor, and then passes through a filter circuit composed of LC to become a stable DC output; The control loop is designed as follows: The control circuit includes a proportional operation circuit, a phase angle control circuit, a unidirectional bridge rectifier circuit and an overvoltage protection circuit; The proportional operation circuit is composed of an operator and a resistor, and is used to process the sampling signal. The processed signal is proportional to the sampling signal and is connected to the phase angle control circuit through the power circuit as its control signal. The phase angle control circuit is composed of the phase angle control chip TCA785 and discrete resistor and capacitor components. It uses the voltage input by the proportional operation circuit and the AC synchronization signal as reference. If the voltage increases, the conduction angle of the control signal output by it decreases. If the voltage decreases, the conduction angle of the control signal output by it increases. The conduction angle is based on the synchronization signal introduced from the AC380V power supply input terminal through the transformer as reference. The unidirectional bridge rectifier circuit is composed of rectifier diodes, current limiting resistors, thyristors and other devices, and is equipped with thyristor RC protection circuit and freewheeling circuit; the current limiting resistor is connected in parallel with the AC contactor, and the AC contactor is controlled to close when necessary, which can greatly increase the DC current in the control coil of the three-phase saturated reactor; the main function of the unidirectional bridge rectifier circuit is to change the DC current in the control coil of the three-phase saturated reactor by changing the conduction angle of the thyristor; The overvoltage protection circuit is mainly composed of a voltage comparator, a power tube, a resistor, a capacitor, a light-emitting diode, a delay circuit, and a power drive circuit; the overvoltage protection circuit makes a real-time judgment on the power supply output voltage. When the voltage exceeds the judgment threshold, the voltage comparator outputs a high level, and the threshold voltage indicator light is on. At this time, the delay circuit composed of a single junction transistor continuously judges the high level output by the comparator. If the high level lasts for 4 to 6 seconds, the single junction transistor is turned on, and the system power disconnect indicator light is on. At the same time, the external relay is controlled to disconnect through the thyristor power drive circuit, thereby controlling the contactor control combination to disconnect and cut off the power input.

2. The method for preparing a high-power DC power supply for ground starting of an aircraft according to claim 1, characterized in that: The DC output of the main circuit is used as a sampling signal. After passing through the proportional operation circuit, it is connected to the emitter follower. After power amplification, it passes through the phase angle control circuit (two phases of the 380V AC in the main circuit are taken and stepped down by the transformer as the synchronization signal of the phase angle control circuit). The input generates a phase angle control signal. After isolation, it is connected to the unidirectional bridge rectifier circuit to control the DC current of the control coil in the three-phase saturated reactor.

3. The method for preparing a high-power DC power supply for ground starting of an aircraft according to claim 2, characterized in that: When the input three-phase 380V AC power or load changes, the DC voltage output by the main circuit will also change. For example, when the output voltage increases, the sampling voltage of the control circuit increases, causing the phase angle control signal to change. The phase shift angle increases, which reduces the conduction angle of the thyristor in the unidirectional bridge rectifier circuit, reduces the DC current of the control coil of the three-phase saturated reactor, increases the inductance of the three AC working coils of the three-phase saturated reactor, reduces the primary winding voltage of the main transformer, and reduces the output DC voltage accordingly, so that the output DC voltage is basically maintained at the original level, thereby achieving the purpose of automatic control.

4. The method for preparing a high-power DC power supply for ground starting of an aircraft according to claim 3, characterized in that: The DC output of the main circuit is selected as the sampling signal, and connected to the delay circuit after passing through the voltage comparator. When the DC output of the main circuit exceeds the set overvoltage protection value, the delay circuit starts timing. After reaching the specified time, the control signal is output. After passing through the power drive circuit, the control relay and contactor are controlled to turn on the control module and disconnect the power input to achieve the purpose of overvoltage protection.

Images