Multi-channel high-voltage direct-current power supply system and multiplexing excitation control method thereof

Abstract

The embodiment of the invention discloses a multi-channel high-voltage direct-current power supply system and a multiplexing excitation control method thereof. The multi-channel high-voltage direct current power supply system comprises a permanent magnet exciter, a power generation unit, a direct current-direct current converter, a direct current-alternating current converter, a circuit breaker, a bus bar, a load and a storage battery. A four-channel high-voltage direct-current power supply system is formed by the four generators, the four generators operate independently, and the system has large power generation capacity; a permanent magnet brushless direct current motor is adopted as a permanent magnet exciter, and initial excitation energy is provided for generators of four channels. Excitation of a generator is in an excitation mode combining self excitation and separate excitation, two diodes which are connected in a common cathode mode, a power switch tube and a bus voltage monitoring module are additionally introduced into a power converter of a power generation system, switching of the excitation modes can be achieved, and when the fluctuation of bus voltage is large and system excitation stability is affected, the system excitation stability is influenced. The excitation mode is switched from self excitation to separate excitation, and the excitation mode of the system is more flexible and reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of aviation high-voltage DC power supply systems, and particularly to a multi-channel high-voltage DC power supply system and a multiplexed excitation control method therefor. Background Art

[0002] More-electric / all-electric aircraft have become the main trend in the development of modern aircraft. With the development of aviation electrification, airborne power supply systems such as low-voltage DC (LVDC), constant-frequency AC (CFAC), variable-frequency AC (VFAC), and high-voltage DC (HVDC) have emerged successively. With the substantial increase in the demand for airborne capacity in more-electric aircraft, the high-voltage DC power supply system has the advantages of large capacity, light weight, high efficiency, and high reliability, and has been successfully applied to more-electric military aircraft such as the F-22 and F-35. The high-voltage DC power supply system has gradually become an important feature of advanced more-electric military aircraft power supply systems, and the airborne power grid power supply system has also gradually shown a development trend towards high-voltage DC. At the same time, with the increasing improvement of aircraft performance, the types and quantities of airborne electrical loads have been continuously increasing, and the electrical power demand of the aircraft has also been continuously increasing, and there is an increasing need for a power supply system with large capacity and high stability.

[0003] The system capacity of more-electric aircraft has increased significantly compared with traditional aircraft, and the power supply capacity has increased significantly. The capacity of a single generator can be increased to meet the growing electrical power demand of the aircraft, but it poses a greater challenge to the design of the motor. In addition, multiple channels and multiple generators can be used for power supply. When multiple generators are operating normally, they supply power independently to each channel, and the system has a large power generation capacity. And when it is necessary to supply power to high-power loads, multiple generators can be switched to a parallel power supply mode.

[0004] Switched reluctance motors have great advantages in terms of body structure, manufacturing cost, and performance, and have been widely developed in the fields of aerospace, shipbuilding, chemical engineering, electric vehicles, etc. The common excitation methods of switched reluctance motors mainly include self-excitation and separate excitation. Self-excitation means that the excitation energy of the motor does not need to be provided by an external excitation power supply, but the excitation magnetic field is generated through the working state of the motor itself. By adopting the self-excitation excitation method, no additional excitation power supply or exciter is required, and the control system is relatively simple and the cost is low. However, the stability of the motor excitation magnetic field will be affected by factors such as speed and load, and the controllability of the excitation current is poor. Separate excitation means that an external independent excitation power supply provides excitation energy for the generator throughout the excitation stage. The external power supply can provide a stable excitation current and can adjust the excitation current according to changes in load and speed. However, separate excitation requires an additional exciter, the system structure is more complex than self-excitation, the system cost is higher, and the weight is greater.

[0005] Therefore, how to further improve the power generation capacity of switched reluctance motors and also require that the weight of the control system equipment does not soar has become a topic that needs to be studied. Summary of the Invention

[0006] An embodiment of the present invention provides a multi-channel high-voltage DC power supply system and its multiplexed excitation control method. The use of multi-channel power supply improves the power generation capacity of the power supply system, meets the growing power demand of the aircraft, can output DC power, and can also output AC power according to needs. It is applicable to most application fields and has advantages such as high power generation capacity, high safety and reliability. In addition, the excitation control method adopted combines self-excitation and he-excitation, making the excitation mode of the power generation system more flexible and improving the excitation stability. And only one permanent magnet exciter is used to provide excitation for the generators of 4 channels, which reduces the system cost and lightens the system weight to a certain extent.

[0007] To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

[0008] In a first aspect, the multi-channel high-voltage DC power supply system provided by the embodiments of the present invention, the components of the system include: a permanent magnet exciter (PMG), a power generation system (SRGS), a secondary power supply device (DC-DC converter, DC-AC converter), a circuit breaker, a busbar (270V high-voltage DC busbar, 28V low-voltage DC busbar, 115V AC busbar), a load (high-voltage DC load, low-voltage DC load, AC load), and a battery (270V battery, 28V battery). In the power generation system, n generators form n channels, where n is a positive integer, that is, an n-channel high-voltage DC power supply system is formed by n (n≥2, n = 2, 3, 4...) generators. The power converter of each generator in the power generation system is of an asymmetric half-bridge type and is connected in a split busbar form.

[0009] Among them, the permanent magnet exciter adopts a permanent magnet brushless DC motor, which includes a permanent magnet motor and a rectifier. Its rated output voltage is 100V. It can not only provide excitation voltage for the generator, but also supply power to the controller or other loads after signal conditioning. The controller is a generator controller, which is used to receive rotor position angle, voltage, and current signals, and output drive signals to the power converter to realize functions such as switching of the motor working state and various protections. The circuit breaker is used to control the opening or closing between circuits to realize isolation and protection during power transmission and distribution and in case of faults. The secondary power supply device includes a DC-DC converter and a DC-AC converter. The DC-DC converter can convert the DC power supply voltage on the aircraft into DC voltages of different magnitudes or natures to meet the specific requirements of different electrical equipment for DC voltages. The DC-AC converter converts direct current into alternating current to provide an AC secondary power supply to meet the needs of airborne AC electrical equipment. The busbars include an excitation busbar, a 270V high-voltage DC busbar, a 28V low-voltage DC busbar, and a 115V AC busbar. The output electrical energy of the motor and the converter is supplied to the busbars, and all electrical equipment obtains electrical energy from the busbars, so that electrical energy can be more reasonably and efficiently transmitted to each load end, improving the flexibility and reliability of power supply. The loads include high-voltage DC loads, low-voltage DC loads, and AC loads. The batteries include a 270V battery and a 28V battery, which can be used as an emergency power supply to provide backup power for airborne key systems to ensure the reliability of aircraft power supply. In the preferred solution, n = 4, that is, the power generation system has 4 channels, including generators and corresponding power converters and controllers, and the 4 channels are independent of each other. The generator is a switched reluctance motor with a rated output voltage of 270VDC, and supplies electrical energy to the 270V high-voltage DC busbar.

[0010] Specifically, the connection method of the power converter includes: the positive pole of the external excitation power supply U f is connected in series with the anode of the external excitation diode D t , and the cathode of the external excitation diode D t is connected to the collectors of the power switch tubes on each phase's upper bridge arm, that is, S1, S3, and S5. The negative pole of the external excitation power supply U f is connected to the emitters of the power switch tubes on each phase's lower bridge arm, that is, S2, S4, and S6; the emitters and collectors of the power switch tubes S1 and S2 are respectively connected in series with the A-phase winding and connected to the excitation busbar. The cathodes and anodes of the diodes D1 and D2 are respectively connected in series with the A-phase winding and connected to the power generation busbar. The same applies to phases B and C. The output end of the power generation side busbar passes through a power switch tube S s and a self-excitation diode D s and is connected to the collector of S1, where the emitter of S s is connected to the anode of D s , and D s and D t are connected with a common cathode.

[0011] The types of circuit breakers in the system include: exciter circuit breaker (EB), generator circuit breaker (GCB), bus tie breaker (BTB), DC-DC converter breaker (CONB), DC-AC inverter breaker (INVB), and distribution breaker (DB). Among them, the permanent magnet exciter (1) is connected to the excitation bus bar (3) through the excitation circuit breaker EB (11). The excitation bus bar is connected to four groups of power generation systems (2) through four switches S1, S2, S3, and S4 respectively. Taking channel 1 as an example, the power generation system (2) is connected to the 270V high-voltage DC bus bar (8) through the generator circuit breaker GCB (12). The 270V battery (7) and the high-voltage DC load (6) are connected to the 270V high-voltage DC bus bar (8) through the distribution breaker DB (16). The DC-DC converter (4) is connected to the 270V high-voltage DC bus bar (8) through the CONB (15). The DC-AC inverter (5) is connected to the 270V high-voltage DC bus bar (18) through the INVB (14). The output of the DC-DC converter (4) is connected to the low-voltage DC bus bar (9), and then connected to the low-voltage DC load (18) and the 28V battery (17) through the distribution breaker DB (16). The output of the DC-AC inverter (5) is connected to the 115V AC bus bar (10), and then connected to the AC load (19) through the distribution breaker DB (16). The same applies to channels 2-4. In addition, the high-voltage DC bus bars (8) of the four channels are connected to each other through the bus tie breaker BTB (13).

[0012] In a second aspect, the method provided by the embodiment of the present invention includes: an external excitation link and a self-excitation link; wherein, the excitation method of the multi-channel high-voltage DC power supply system is a combination of separately excited and self-excited, and the excitation mode is switched through two diodes D t , D s connected in common cathode in the power converter and the power switch tube S s , and the power switch tube S s is in a closed state initially;

[0013] In the external excitation link, the permanent magnet exciter provides excitation energy for four generators in sequence until the voltage is built up;

[0014] In the self-excitation link, when the voltage at the power generation bus bar end is greater than the output voltage of the exciter, at this time D s conducts and D t is cut off, and the excitation energy is provided by the voltage at the power generation bus bar end;

[0015] If it is detected that the voltage of the power generation bus bar fluctuates during self-excitation, the external excitation link is switched back. In addition, when the permanent magnet exciter does not work as an excitation source, it can be conditioned by signals to supply power to the controller and other loads in the power supply system.

[0016] Among them, the methods for detecting the dynamic voltage of the power generation bus during self-excited excitation include: when the excitation energy is provided by the output terminal voltage, by detecting the bus output voltage, the maximum value, minimum value, and average value of the bus voltage are respectively obtained, and the amplitude of the fluctuating voltage is calculated; among them, the allowable range of the bus output voltage fluctuation is: not exceeding ±3% of the stable amplitude of the output voltage. If the bus voltage fluctuation is within the allowable range, then S s remains off, and the system is still self-excited; if the bus voltage fluctuation exceeds the allowable range, then the switch S s is disconnected. At this time, D s is also cut off, and D t re-conducts, and the system switches back to external excitation to ensure stable excitation.

[0017] The multi-channel high-voltage DC power supply system and its multiplexed excitation control method provided by the embodiments of the present invention consist of 4 generators to form a 4-channel high-voltage DC power supply system. The 4 generators operate independently, and the system has a large power generation capacity; a permanent magnet brushless DC motor is used as a permanent magnet exciter to provide initial excitation energy for the generators of 4 channels. When the permanent magnet exciter is not used as an excitation source, it can also supply power to the controller or other loads after signal conditioning; the excitation of the generator is a combined excitation method of self-excitation and he-excitation. Two diodes connected in common cathode, a power switch tube, and a bus voltage monitoring module are additionally introduced in the power converter of the power generation system, which can realize the switching of the excitation method, and when the bus voltage fluctuates greatly and affects the stability of the system excitation, the excitation method is switched from self-excitation to he-excitation, and the system excitation method is more flexible and reliable. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is the architecture diagram of the multi-channel high-voltage DC power supply system proposed by the present invention;

[0020] Figure 2 It is the control block diagram of the power generation system in the present invention;

[0021] Figure 3 It is the schematic diagram of the power converter in the present invention;

[0022] Figure 4 It is the schematic diagram of the permanent magnet exciter providing excitation energy for the generator in the present invention;

[0023] Figure 5Schematic diagram of providing excitation energy for the generator by the voltage of the power generation busbar in the present invention;

[0024] Figure 6 Control block diagram of the excitation method in the present invention;

[0025] Figure 7 Flowchart of switching the excitation method in the present invention.

[0026] The numerical marks in the drawings respectively represent: permanent magnet exciter - 1, power generation system - 2, excitation busbar - 3, DC - DC converter - 4, DC - AC converter - 5, high - voltage DC load - 6, storage battery - 7, high - voltage DC busbar - 8, low - voltage DC busbar - 9, AC busbar - 10, excitation circuit breaker EB - 11, generator circuit breaker GCB - 12, busbar connection circuit breaker BTB - 13, DC - AC converter circuit breaker INVB - 14, DC - DC converter circuit breaker CONB - 15, distribution circuit breaker DB - 16, storage battery - 17, low - voltage DC load - 18, AC load - 19. Detailed implementation manners

[0027] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below in conjunction with the drawings and specific implementation manners. The implementation manners of the present invention will be described in detail below. Examples of the implementation manners are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The implementation manners described below by referring to the drawings are exemplary and are only used to explain the present invention, and cannot be construed as a limitation of the present invention. Those skilled in the art of this technology can understand that unless specifically stated, the singular forms "a", "an", "the" and "said" used here may also include the plural forms. It should be further understood that the term "comprising" used in the description of the present invention means the presence of the described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or their groups. It should be understood that when we say an element is "connected" or "coupled" to another element, it can be directly connected or coupled to other elements, or there may also be intermediate elements. In addition, the "connection" or "coupling" used here may include wireless connection or coupling. The phrase "and / or" used here includes any unit and all combinations of one or more of the associated listed items. Those skilled in the art of this technology can understand that unless otherwise defined, all terms (including technical terms and scientific terms) used here have the same meaning as the general understanding of those of ordinary skill in the field to which the present invention belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless defined as here.

[0028] To describe the present invention more specifically, the technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments in the examples of the present invention. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. To achieve the above object, according to the first aspect of the present invention, a multi-channel high-voltage DC power supply system is provided, as Figure 1-7 shown. The system includes: a permanent magnet exciter (PMG), a power generation system (SRGS), an excitation busbar, a DC-DC converter, a DC-AC converter, a circuit breaker, a busbar, a load, and a storage battery. Figures 1 to 6 The permanent magnet exciter 1 uses a permanent magnet exciter with a relatively large capacity as the excitation source of the entire power supply system to provide the initial excitation energy during the voltage building stage for the power generation system. The rated output voltage U of the permanent magnet exciter

[0029] is 100 VDC, and it provides excitation for the generators of 4 channels in sequence. The permanent magnet exciter can not only provide excitation energy for the generator, but also, when it does not work as an excitation source, supply power to the controller and other loads in the system after signal conditioning. f The power generation system 2 is composed of 4 switched reluctance motors and their corresponding power converters and controllers to form the power generation system of the multi-channel high-voltage DC power supply system. The 4 motors operate independently and all output 270 VDC.

[0030] The electromechanical energy conversion principle of the switched reluctance motor is the interaction form between the magnetic field and the magnetically permeable material. Its stator and rotor are both salient pole structures. There are no windings or permanent magnets on the rotor, and there are concentrated windings on the stator. The structure is simple and reliable, enabling the switched reluctance motor to operate at high speeds; moreover, the windings of each phase of the switched reluctance motor are independent of each other. Different from the traditional three-phase sinusoidal power supply windings that need to generate a rotating magnetic field to work, the switched reluctance motor can operate with a phase missing, has high reliability, and strong fault tolerance ability. Using a four-channel switched reluctance motor to form the power generation unit of the power supply system can greatly improve the power generation capacity of the system and meet the growing electricity demand of the aircraft.

[0031] The power converter is the hardware core of the power generation system. By means of a power converter composed of controllable switch devices, by receiving the PWM drive signal output by the controller and controlling the on and off of the switch tubes of each phase, the windings of each phase of the motor can operate independently and orderly, realizing the switching of the excitation and power generation states of each phase of the motor. Common power converters mainly include motor double-winding type, asymmetric half-bridge type, capacitor energy storage type, resonant switch type, etc. The present invention includes four groups of mutually independent asymmetric half-bridge power converters, all of which adopt the form of split busbars, separating the original single busbar into independent power generation busbars and excitation busbars. The specific connection method of the power converter is: the output voltage U of the permanent magnet exciter

[0032] f ​The positive electrode of [device] is connected in series with the anode of the separately excited diode D t The cathode of the separately excited diode D t is connected to the collectors of the power switch tubes on the upper bridge arm of each phase, namely S1, S3, and S5. The negative electrode of U f is connected to the emitters of the power switch tubes on the lower bridge arm of each phase, namely S2, S4, and S6, and provides the initial excitation energy for voltage building for 4 generators in sequence; each phase is connected to the excitation bus and the power generation bus through two power switch tubes and two diodes respectively. Taking phase A as an example, the power switch tubes S1 and S2 are respectively connected in series with both ends of the phase A winding and connected to the excitation bus, and the diodes D1 and D2 are respectively connected in series with both ends of the phase A winding and connected to the power generation bus. The same applies to phases B and C.

[0033] The power switch tubes S1, S2, S3, S4, S5, S6 and S s are all fast fully controlled power electronic devices, and IGBT, MOSFET or SiC devices can be used.

[0034] The diode D s 、D t are ordinary diodes, and D1, D2, D3, D4, D5, and D6 are freewheeling diodes.

[0035] The controller is used to control the on and off of the switch tubes in each phase of the power converter. By comprehensively processing the voltage, current, and rotor position angle signals, it outputs PWM drive signals according to the given control logic, acts on the power converter, and controls the on and off of the switch tubes in each phase of the converter to achieve functions such as motor operating state switching and various protections.

[0036] The excitation busbar 3 has an excitation busbar voltage of 100VDC. During normal system operation, the permanent magnet exciter provides excitation energy for the generators in 4 channels in sequence, and disconnects from the generators after voltage building is completed. This excitation busbar can also be connected to the controller or other loads after signal conditioning to supply power to these modules.

[0037] The DC-DC converter 4, that is, the DC / DC converter, can convert the 270VDC voltage output by the power generation unit bus into direct current of other levels for use by DC loads of different voltage levels. Here, it converts 270VDC into 28VDC, and the output electrical energy is supplied to the 28V low-voltage DC busbar.

[0038] The DC-AC converter 5, that is, the DC / AC converter, converts the 270VDC voltage output by the power generation unit bus into 115VAC alternating current, and the output electrical energy is supplied to the 115VAC busbar.

[0039] Loads mainly include common loads of the airborne system, including high-voltage DC loads, low-voltage DC loads and AC loads, such as lighting systems, environmental control systems, power systems and drive devices, communication systems, radar systems, etc.

[0040] The batteries include 270V batteries and 28V batteries, which can be used as auxiliary power supplies to supply power to electrical equipment such as lighting systems and air conditioners.

[0041] Busbars include 270V high-voltage DC busbars, which supply power to high-voltage DC loads, DC-DC converters, DC-AC converters and 270V batteries; 28V low-voltage DC busbars, which supply power to low-voltage DC loads and 28V batteries; 115V AC busbars, which supply power to AC loads.

[0042] Circuit breakers include exciter circuit breaker EB, generator circuit breaker GCB, busbar connection breaker BTB, DC-DC converter breaker CONB, DC-AC converter breaker INVB, and distribution breaker DB, which are respectively connected to the exciter and the excitation busbar, the generator and the high-voltage DC busbar, the busbar and the DC-DC converter, the busbar and the DC-AC converter, and the busbar and the load to control the connection or disconnection between circuits.

[0043] Next, the excitation control method for the multiplexing of the multi-channel high-voltage DC power supply system proposed by the present invention will be introduced. As Figure 6 、 7 shown, the common excitation methods of switched reluctance motors mainly include separately excited and self-excited. Self-excitation provides excitation energy for the windings through the output voltage of the motor itself, without the need for an additional excitation power supply. The system has a smaller volume and weight and a high power density. However, the stability of the excitation magnetic field will be affected by factors such as load and speed. For example, when the output voltage fluctuates greatly, the excitation current is not easy to control, which not only affects the quality of the generated voltage but also the stable operation of the system. Separately excited means that during the entire excitation process, an external exciter provides excitation energy for the generator. Compared with the self-excited excitation mode, the excitation is more stable, more controllable and flexible, but the system has a larger volume and weight, higher cost, and increased complexity of the control system.

[0044] Comparing the above two excitation methods and integrating the advantages of the two excitation methods, a combined excitation method of separately excited and self-excited is considered: separately excited is adopted in the initial stage of excitation, and an external excitation source provides excitation energy. The present invention uses a permanent magnet exciter with a rated output voltage of 100VDC as the excitation source, and the rated output voltage of the permanent magnet exciter is lower than the busbar output voltage of the power generation system; when the busbar voltage at the power generation end is higher than the excitation voltage, two diodes D s and D tUnder the action of this, the diode with a high anode voltage conducts, and the diode with a low anode voltage is turned off. At this time, diode D t is cut off, and diode D s connected to the generator output terminal conducts, switching to providing excitation energy by the output voltage of the generator itself, which is self-excitation excitation, realizing the switching of the excitation mode.

[0045] However, once the output voltage fluctuates greatly, the difficulty of controlling the excitation current increases, which will have an adverse impact on the excitation of the motor. Therefore, a switching tube S s is introduced and connected in series with D s . The initial state of S s is closed, and an output voltage detection module is added to detect the magnitude of the output voltage fluctuation, measure the maximum value, minimum value and average value of the output voltage respectively, calculate the fluctuation value of the output voltage, determine whether the bus voltage fluctuation is within the allowable range, and then output the drive signal of switching tube S s to control its on and off. When the output voltage fluctuation exceeds ±3% of the stable amplitude of the output voltage, the output drive signal is 0, and switching tube S s is cut off, switching from self-excitation to external excitation. At this time, the excitation energy is supplied by the permanent magnet exciter; if the output voltage fluctuation does not exceed ±3% of the stable amplitude of the output voltage and is within the allowable range of fluctuation, the output drive signal is 1, and switching tube S s remains closed and is still self-excitation excitation. Through the above method, the excitation mode of the power generation system is made more flexible and reliable, and the excitation cost of the system is reduced to a certain extent: only 1 permanent magnet brushless DC motor provides excitation energy for 4 generators. When switching to self-excitation, no external additional excitation source is required, which reduces the weight of the system to a certain extent and improves the system efficiency. And when the external exciter no longer provides excitation energy for the generator, it can also supply power to the controller and other loads in the system, improving the power utilization efficiency to a certain extent.

[0046] The multi-channel high-voltage DC power supply system proposed in the present invention consists of four switched reluctance motors to form four power generation channels, which improves the power supply capacity of the entire power supply system. The generators of each channel are respectively equipped with independently operating controllers and power converters. The converter composed of power switching tubes can make the windings of each phase of the switched reluctance motor conduct in a certain phase sequence in turn. In the form of an asymmetrical half-bridge, each phase is independent, and the motor winding is connected in series with the power switching tubes of each phase, without the potential fault of direct connection between the upper and lower bridge arms. The use of multi-channel power supply improves the power generation capacity of the power supply system, meets the growing power consumption needs of the aircraft, can output DC power, and can also output AC power according to needs, is applicable to most application fields, and has advantages such as high power generation capacity and high safety and reliability. In addition, the excitation control method adopted is a combination of self-excitation and he-excitation, making the excitation mode of the power generation system more flexible and improving the excitation stability. And only one permanent magnet exciter is used to provide excitation for the generators of 4 channels, which reduces the system cost and lightens the system weight to a certain extent. The first object of the present invention is to provide a multi-channel high-voltage DC power supply system architecture, and the second object is to provide an excitation control method applied to the multi-channel high-voltage DC power supply system to solve the problems of low power generation capacity and high excitation cost of the existing high-voltage DC power supply system.

[0047] To achieve the above first object, the present invention provides a multi-channel high-voltage DC power supply system, which includes a permanent magnet exciter (PMG), a power generation system (SRGS), an excitation busbar, a DC-DC converter, a DC-AC converter, a circuit breaker, a 270V high-voltage DC busbar, a 28V low-voltage DC busbar, a 115V AC busbar, a load, and a battery. A permanent magnet brushless DC motor is used as the permanent magnet exciter, and through the excitation busbar, the excitation energy in the initial voltage building stage is provided for four power generation channels in turn. Four power generation systems of four channels are respectively composed of four switched reluctance motors and their corresponding controllers and power converters. The controller comprehensively processes the voltage, current, and rotor position angle signals, and outputs a drive signal to control the on and off of the switching tubes of each phase of the power converter; the power converter adopts an asymmetrical half-bridge and is connected to the three-phase windings of the generator to control the independent and orderly operation of the windings of each phase of the motor, and in the form of a split busbar, the original single busbar is separated into an independent power generation busbar and an excitation busbar. All the busbars in the power supply system are connected to electrical equipment through circuit breakers to achieve isolation and protection during power transmission, distribution, and faults.. The specific connection method of the power converter is as follows: the positive pole of the output voltage U f of the externally connected permanent magnet exciter is connected in series with the anode of the he-excitation diode D t , and the cathode of the he-excitation diode D t is connected to the collectors of the power switching tubes of the upper bridge arm of each phase, that is, S1, S3, and S5. U fThe negative electrode of [[ID=]] is connected to the emitters of the power switching transistors of the lower bridge arm of each phase, namely S2, S4, and S6, to provide the excitation energy for the generator during the voltage build-up stage; each phase is connected to the excitation bus and the power generation bus through two switching transistors and two diodes respectively. The emitter of power switching transistor S1 and the collector of S2 are respectively connected in series to both ends of the A-phase winding and then connected to the excitation bus. The cathode of diode D1 and the anode of D2 are respectively connected in series to both ends of the A-phase winding and then connected to the power generation bus. The same applies to phases B and C, that is, S3 and S4 are connected in series with the B-phase winding to the excitation bus, D3 and D4 are connected in series with the B-phase winding to the power generation bus, S5 and S6 are connected in series with the C-phase winding to the excitation bus, and D5 and D6 are connected in series with the C-phase winding to the power generation bus. The power switching transistor S s is connected in series with the self-excitation diode D s and they are jointly connected to the collector of S1, where the emitter of S s is connected to the anode of D s , and D s and D t are connected in a common cathode configuration.

[0048] To achieve the above second objective, the present invention provides an excitation control method for a multi-channel high-voltage DC power supply system. Based on the operating principle of a switched reluctance motor, on the basis of a traditional power converter, two additional diodes and one power switching transistor are introduced, and a single bus is divided into a power generation bus and an excitation bus. By using two diodes D t and D s connected in a common cathode configuration, it is ensured that when the power generation voltage is greater than the excitation voltage, the external excitation power supply is disconnected and switched to self-excitation to achieve the conversion of the excitation mode. In addition, D s is connected in series with a power switching transistor S s . S s is in a closed state initially, and a bus voltage monitoring device is added to monitor the bus voltage fluctuations. When the motor is in self-excitation, if the bus voltage fluctuation exceeds ±3% of its stable amplitude, a control signal 0 is output to turn off S s , and the self-excitation mode is switched to the hexa-excitation mode; if the bus voltage fluctuation is within the allowable range, a control signal 1 is output to keep S s closed, and the self-excitation mode is continued.

[0049] The multi-channel high-voltage DC power supply system proposed by the present invention has a higher power generation capacity compared to the traditional power supply system, can meet the growing power consumption needs of aircraft, and can improve the stability of the power supply system to a certain extent; in addition, the proposed excitation method combines self-excitation and hexa-excitation, integrating the advantages of both excitation methods, making the excitation mode of the power generation system more flexible and stable, and reducing the excitation cost of the system to a certain extent, reducing the system weight, and increasing the power density of the system.

[0050] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the device embodiments, since they are basically similar to the method embodiments, the description is relatively simple. For the relevant parts, reference can be made to the corresponding descriptions in the method embodiments. As mentioned above, the above are only the specific implementation manners of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A multi-channel high-voltage DC power supply system, characterized in that The components of the system include: a permanent magnet exciter, a power generation system, a secondary power supply device, a circuit breaker, a busbar, a load, and a storage battery; In the power generation system, n channels are formed by n generators, where n is a positive integer and n≥2; The power converter of each generator in the power generation system is of an asymmetric half-bridge type and is connected in a split busbar form.

2. The multi-channel high-voltage DC power supply system according to claim 1, characterized in that, The connection methods of the power converter include: External excitation power supply U f The positive pole of is connected in series with the anode of the external excitation diode D t The cathode of the external excitation diode D t is connected to the collectors of the three power switching tubes S1, S3, and S5 on the upper bridge arm of each phase. The negative pole of the external excitation power supply U f is connected to the emitters of the three power switching tubes S2, S4, and S6 on the lower bridge arm of each phase; The emitter of power switch tube S1 and the collector of S2 are respectively connected in series with the A-phase winding and connected to the excitation busbar; The cathode of diode D1 and the anode of D2 are respectively connected in series with the A-phase winding and connected to the power generation busbar; The output terminal of the power generation side bus passes through a power switch tube S s and a self-excited diode D s and is connected to the collector of S1, where the emitter of S s is connected to the anode of D s and D s and D t are connected with a common cathode.

3. The multi-channel high-voltage DC power supply system according to claim 1, wherein The types of circuit breakers in the system include: an exciter circuit breaker (EB), a generator circuit breaker (GCB), a busbar connection circuit breaker (BTB), a DC-DC converter circuit breaker (CONB), an inverter circuit breaker (INVB), and a distribution circuit breaker (DB).

4. The multi-channel high-voltage DC power supply system according to claim 1, characterized in that The permanent magnet exciter is connected to the excitation busbar through EB, and the excitation busbar is respectively connected to four groups of power generation systems through four switches S1, S2, S3, and S4. Among them, the power generation system of each channel is connected to the high-voltage DC busbar through GCB, and the high-voltage DC busbars of each channel are connected to each other through BTB; The storage battery and the high-voltage DC load are connected to the high-voltage DC busbar through DB, the DC-DC converter is connected to the high-voltage DC busbar through CONB, and the inverter is connected to the high-voltage DC busbar through INVB; The output of the DC-DC converter is connected to the low-voltage DC busbar, and then connected to the low-voltage DC load and the storage battery through DB; The output of the inverter is connected to the AC busbar, and then connected to the AC load through DB.

5. The multi-channel high-voltage DC power supply system according to claim 1, characterized in that, n＝4。 6. A multiplexed excitation control method for a multi-channel high-voltage DC power supply system, characterized in that The excitation mode of the multi-channel high-voltage DC power supply system is a combination of separately excited and self-excited. Through two diodes D t and D s connected in common cathode in the power converter and the power switch tube S s , the switching of the excitation mode is carried out, where the power switch tube S s is in the closed state initially; The method includes: an external excitation link and a self-excitation link; In the external excitation link, the permanent magnet exciter provides excitation energy for 4 generators in sequence until the voltage is built up; In the self-excitation excitation link, the voltage at the power generation busbar end is greater than the output voltage of the exciter. At this time, D s conducts and D t is cut off, and the excitation energy is provided by the voltage at the power generation busbar end; If it is detected that the voltage of the power generation busbar fluctuates during self-excitation, the system switches back to the external excitation link.

7. The method according to claim 6, characterized in that The methods for detecting the voltage of the power generation busbar during self-excitation include: When the excitation energy is provided by the output voltage, by detecting the busbar output voltage, the maximum value, minimum value, and average value of the busbar voltage are respectively obtained, and the amplitude of the fluctuating voltage is calculated; Among them, the allowable range of the busbar output voltage fluctuation is: not exceeding ±3% of the stable amplitude of the output voltage.

8. The method according to claim 7, characterized in that, If the bus voltage fluctuation is within the allowable range, then S s remains off; If the bus voltage fluctuation exceeds the allowable range, then switch S s is turned off. At this time, D s is also cut off, and D t is turned on again.

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