Two-stage starter system for electric propulsion aircraft power supply engine and design method

Abstract

The invention relates to the technical field of two-stage starters, in particular to a two-stage starter system for an electric propulsion aircraft power supply engine and a design method, the two-stage starter system comprises a two-stage starter and a controller, and the two-stage starter comprises an exciter, a rotary rectifier, a main motor and a rotary transformer. According to the two-stage starter system for the electric propulsion aircraft power supply engine and the design method, compared with an air entraining starting mode of the engine, an auxiliary power device is omitted, and compared with electric starting based on a brush direct current motor, the defects that high pressure is not suitable, and a clutch cannot meet the large-torque application requirement are overcome; compared with electric starting based on a brushless permanent magnet motor, the defect that a clutch is difficult to meet the non-torque application requirement is overcome, in a direct-current solid-state relay, resistors are connected to the two ends of a series power tube in parallel, the power-on impact current is restrained, meanwhile, voltage sharing of the series power tube is achieved, and for bridge arms in a three-phase full bridge and an alternating-current excitation power supply, the direct-current solid-state relay is connected in parallel.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of two-stage starter, in particular to a two-stage starter system for a power supply engine of an electric propulsion aircraft and a design method. BACKGROUND

[0002] An electric propulsion aircraft refers to an aircraft that uses an electric fan to generate flight thrust. It includes pure electric propulsion, parallel hybrid electric propulsion, and series hybrid electric propulsion. For pure electric propulsion, only batteries are used as power sources. However, due to the low power density of current batteries, they are not suitable for long-time flight use of more than 30 minutes. For parallel hybrid electric propulsion, the thrust of the aircraft is provided by both a fuel engine and a battery. However, since the engine is directly coupled to the fan that generates thrust, the efficiency of the fuel engine is limited. For series hybrid electric propulsion, the engine converts fuel energy into electrical energy through a power converter, and the output of the power converter is connected in parallel with a high-voltage battery to supply power to the fan that generates thrust. The power supply engine is not directly coupled to the fan that generates thrust, so the fuel engine has been significantly improved. The two-stage starter system involved in the present patent is mainly applied to series hybrid electric propulsion aircrafts.

[0003] Compared with traditional aircrafts that generate thrust through traditional fuel engines, the electric propulsion aircraft has the advantages of high maneuverability and high fuel utilization rate. Since the electric propulsion fan responds to the input driving power faster than the fuel engine responds to the input fuel, the maneuverability of the aircraft has been significantly improved. Since the traditional fuel engine works in a variable speed state, the thrust of the engine is determined by extreme conditions such as take-off and high-speed maneuvering, which results in the engine being in a light load state during long-time cruising, low engine fuel efficiency, and thus low fuel utilization rate. However, the power supply engine of the electric propulsion aircraft works in a constant speed state and is only used to provide constant speed steady flight thrust. The thrust of the aircraft in extreme conditions such as take-off and high-speed maneuvering is provided by the battery, and the fuel engine works at the ideal working condition point for a long time, which significantly improves the efficiency. This is the principle of the improvement of the fuel utilization rate of the electric propulsion aircraft.

[0004] Since the electric energy generated by the engine is mainly used to drive the fan that generates thrust, and the power consumption is large, using a 1kV high-voltage direct current power supply is a reasonable choice for 500kW~2MW electric propulsion aircrafts to achieve high efficiency. Since the parallel battery changes with the change of electric energy, it will fluctuate in the range of 800V~1200V. The starter system of the starting engine needs to be powered by an 800V~1200V high-voltage direct current power supply.

[0005] Traditional engine starting usually includes air starting, electric starting based on brush DC motor, electric starting based on brushless permanent magnet motor, etc. Air starting is mainly applied to the starting of main engine. The application of electric starting based on brush DC motor includes the starting of auxiliary power device and the low-voltage DC starter-generator system of low-power engine. Electric starting based on brushless permanent magnet motor is mainly applied to the starting of auxiliary power device. For air starting, the auxiliary power device is first started by an electric starter, and then the main engine is started by the air energy generated by the auxiliary power device. For electric starting based on brush DC motor, when applied to the starting of auxiliary power device, a 28V low-voltage DC power supply directly drives the brush DC motor to work, drives the starting of the auxiliary power device, and after the starting is completed, a mechanical clutch is used to disconnect the coupling between the auxiliary power device and the brush DC motor, which is used to prevent the brush DC motor from working at an unendurable high speed and solve the problem of short service life of the brush DC motor; when applied to the low-voltage DC starter-generator system, the 28V low-voltage DC power supply directly drives the brush DC motor to work, realizes the starting of the engine, and after the starting is completed, the engine drives the brush DC motor to work, enters the generating state, and outputs 28V low-voltage DC power. For electric starting based on brushless permanent magnet motor, a 28V low-voltage DC power supply is used to supply power to the controller, the controller drives the brushless permanent magnet motor to work, realizes the starting of the auxiliary power device, and after the starting is completed, a mechanical clutch is used to disconnect the coupling between the auxiliary power device and the brush DC motor, which is used to prevent the permanent magnet motor from working at a high speed, output a high voltage that cannot be borne by the controller, and solve the problem that the permanent magnet motor cannot be de-excited to realize fault protection when working in the generating state. The traditional engine starting method has the following deficiencies: For air starting, since the electric propulsion flight is already equipped with a high-voltage battery, which is sufficient to meet the electric starting demand of the engine, it is unnecessary to add an auxiliary power device to start the engine. For electric starting based on brush DC motor, the brush DC motor is not suitable for a DC power supply of 50V or above, and the voltage level that can be borne is far from the 1kV high-voltage DC power supply used in electric propulsion flight; the impact current is large during starting, which has a great influence on the power supply; and the clutch used to disconnect the coupling between the auxiliary power device and the brush DC motor is difficult to apply to the engine which needs a large torque during the starting process. For electric starting based on brushless permanent magnet motor, the clutch used to disconnect the coupling between the auxiliary power device and the brush DC motor is difficult to apply to the engine which needs a large torque during the starting process. SUMMARY

[0006] The purpose of the present application is to solve the problems in the background art, and provide a two-stage starter system for power supply engine of electric propulsion aircraft and a design method thereof. u and C d ; the stator field winding F+ and F- of the exciter are respectively connected with the output + and - of the AC excitation power supply, the A, B and C terminals of the stator armature winding of the main motor are respectively connected with the A, B and C terminals of the output of the three-phase full bridge, the output speed position signal P of the rotary transformer is connected with the control circuit, the negative pole of the high-voltage DC bus is respectively connected with the input negative pole of the auxiliary power supply, the input negative pole of the AC excitation power supply and the input negative pole of the three-phase full bridge, the positive pole of the high-voltage DC bus is respectively connected with the input positive pole of the auxiliary power supply and the input terminal of the DC solid-state relay through the anode of the diode D and the cathode of the diode D, the output terminal of the DC solid-state relay is respectively connected with the input negative pole of the AC excitation power supply and the input negative pole of the three-phase full bridge, the output terminal of the DC solid-state relay is connected with the negative pole of the high-voltage DC bus through the capacitor C u , the voltage node N and the capacitor C d , the input N terminal of the AC excitation power supply and the input N terminal of the three-phase full bridge are respectively connected with the voltage node N, the output of the auxiliary power supply is respectively connected with the power supply terminal of the control circuit and the power supply terminal of the drive circuit, the control circuit is connected with the drive circuit, the drive circuit outputs the drive signals G A , G B and G C are respectively connected with the DC solid-state relay, the three-phase full bridge and the AC excitation power supply, the output excitation current signal iF of the AC excitation power supply is connected with the control circuit, and the three-phase current signal i ABC of the three-phase full bridge is connected with the control circuit.

[0007] The DC solid-state relay comprises power tubes Q A1 and Q A2 , resistors R A1 and R A2 ; the input terminal of the DC solid-state relay is connected with the emitter C of Q A1 , the collector E of Q A1 is connected with the emitter C of Q A2 , the collector E of Q A2 is connected with the output terminal of the DC solid-state relay, the resistors RA1 are respectively connected with the emitter C and the collector E of Q A1 , the resistors R A2 are respectively connected with the emitter C and the collector E of Q A2The emitter C and collector E are connected together.

[0008] The three-phase full bridge includes phases A, B, and C, and a current sensor S. A S B and S C For any x-phase bridge arm, x = A, B, or C, including power transistor Q... xuo Q xui Q xdi Q xdo diode D xu and D xd For any phase x, it is formed by the positive input of the three-phase full-bridge and Q. xuo The collector C is connected, Q xuo The emitter E is respectively with Q xui collectors C and D xu The cathode is connected, and the emitter E of Qxui is connected to Q. xdi The collector C is connected to the output x terminal of the three-phase full-bridge, Q xdi The emitter E is respectively with Q xdo collectors C and D xd Anode connection, Q xdo The emitter E is connected to the negative input of the three-phase full-bridge, and the N-terminal input of the three-phase full-bridge is connected to D. xu anode and D xd Cathode connection, current sensor S x Detect the current at the x-terminal output of the three-phase full-bridge bridge, and output the current signal i. x It is connected to the control circuit.

[0009] The AC excitation power supply includes bridge arms 1 and 2, and a current sensor S. F For any bridge arm y, y = 1 or 2, including power transistor Q yuo Q yui Q ydi Q ydo diode D yu and D yd For any bridge arm y, it is connected to the positive input terminal of the AC excitation power supply and Q. yuo The collector C is connected, Q yuo The emitter E is respectively with Q yui collectors C and D yu Cathode connection, Q yui The emitter E is respectively with Q ydi The collector C is connected, Q ydi The emitter E is respectively with Q ydo The collector C and the anode of Dyd are connected, Q ydoThe emitter E of the Q is connected with the input negative pole of the AC excitation power supply, the input N end of the AC excitation power supply is connected with the anode of the Dyu and the cathode of the Dyd respectively, the output end of the AC excitation power supply is connected with the collector E of the Q 1ui The collector E of the Q is connected with the output end of the AC excitation power supply, the output end of the AC excitation power supply is connected with the collector E of the Q 2ui The collector E of the Q is connected with the output end of the AC excitation power supply, the output end of the AC excitation power supply is connected with the collector E of the Q F The current sensor S detects the output end current of the AC excitation power supply, and an excitation current signal iF is connected with the control circuit.

[0010] The auxiliary power supply includes a high-voltage input isolation power supply, an 18V-75V input isolation power supply, a 12V isolation power supply, a 5V power supply, an AC power supply and a 5V isolation power supply; the auxiliary power supply is composed of the input positive pole and the input negative pole of the auxiliary power supply being connected with the input positive pole and the input negative pole of the high-voltage input isolation power supply respectively, the output positive pole and the output negative pole of the high-voltage input isolation power supply being connected with the input positive pole and the input negative pole of the 18V-75V input isolation power supply respectively, the output positive pole and the output negative pole of the 18V-75V input isolation power supply being connected with the input positive pole and the input negative pole of the 5V isolation power supply and the 12V isolation power supply respectively, the output positive pole and the output negative pole of the 5V isolation power supply being connected with the voltage node 5V and DGND respectively, the output positive pole and the output negative pole of the 12V isolation power supply being connected with the voltage node T12V and TGND respectively, the voltage node T12V and TGND being connected with the input positive pole and the input negative pole of the 5V power supply and the AC power supply respectively, the output positive pole and the output negative pole of the 5V power supply being connected with the voltage node T5V and TGND respectively, and the two AC output ends of the AC power supply being connected with the voltage node vp+ and vp- respectively.

[0011] The high-voltage input isolation power supply includes a power supply main circuit and a power supply driving circuit, the power supply main circuit includes capacitors C au and C ad , LLC full-bridge 1 and LLC full-bridge 2, for any LLC full-bridge z, z=1 or 2, including power tubes Q z1 ~Q z4 , diodes D z1 ~D z5 , capacitors C z1 ~C z3 , transformers T z1 , and the power supply driving circuit includes a hysteresis comparison circuit, resistors R1 and R2, a capacitor C1, a 15V voltage stabilizing tube Z1, an NPN triode Q1, a P-gate MOS tube Q2, a two-way PWM circuit and a transformer T; for the power supply main circuit part, the input positive pole and the input negative pole of the high-voltage input isolation power supply are connected with the input positive pole and the input negative pole of the power supply main circuit respectively, the output positive pole and the output negative pole of the high-voltage input isolation power supply are connected with the input positive pole and the input negative pole of the power supply main circuit respectively, the input positive pole of the power supply main circuit is connected with the capacitor C au , the voltage node N a , the capacitor C adThe LLC full-bridge 1 is connected to the negative input of the main power supply circuit. The positive and negative inputs of LLC full-bridge 1 are connected to the positive input of the main power supply circuit and voltage node Na, respectively. The positive and negative inputs of LLC full-bridge 2 are connected to the voltage node Na and negative input of the main power supply circuit, respectively. The positive and negative outputs of the main power supply are connected to the positive and negative outputs of LLC full-bridge 1 and LLC full-bridge 2, respectively. For any LLC full-bridge z, the positive input of LLC full-bridge z is connected to Q... z1 and Q z3 The collector C is connected, and the negative input of the LLC full-bridge z is connected to Q respectively. z2 and Q z4 The emitter E is connected, Q z1 The emitters E and Q z2 The collector C is connected, Q z3 The emitters E and Q z4 The collector C is connected, Q z1 The emitter E passes through capacitor C z1 Inductor L z1 Transformer T z1 The primary windings N1 and Q z3 The emitter E is connected, and the transformer T is connected. z1 One end of the secondary winding N2 is connected to D z1 anode and D z2 Cathode connection, transformer T z1 The other end of the secondary winding N2 is connected to D z3 anode and D z4 The cathode connection is such that the positive output of the LLC full-bridge z is connected to D. z1 cathode and D z3 The cathode connection is such that the negative output of the LLC full-bridge z is connected to D. z2 anode and D z4 The anode connection, capacitor C z2 The two ends are connected to the positive and negative output terminals of the LLC full-bridge circuit, respectively, and the transformer T... z1 One end of the auxiliary winding N3 is connected to D z5 anode, D z5 Cathode, voltage node V s Capacitor C z3 respectively with T z1 The other end of the auxiliary winding N3 is connected to the negative input terminal of the main power supply circuit; for the power drive circuit section, the positive input terminal of the high-voltage input isolation power supply is connected to the voltage node V via resistor R1. c Capacitor C1 is connected to the negative input terminal of the high-voltage input isolation power supply. The negative input terminal of the high-voltage input isolation power supply is connected to the anode of Z1 and the negative power supply terminal GND of the dual-channel PWM circuit, respectively. Voltage node V cThe source S of Q2, the drain D of Q2 and the positive supply V of the two-way PWM circuit are connected cc Connection, V c The gate G of Q2 is connected with the hysteresis comparison circuit, and the voltage node V s The collector C of Q1, the emitter E of Q1 and the positive supply V of the two-way PWM circuit are connected cc Connection, voltage node V s The base B of Q1 and the cathode of Z1 are connected with the resistance R2 respectively, and the two ends of the primary winding N1 of the transformer T are connected with the drive output G A and G B of the two-way PWM circuit respectively, the drive signal G 21 , N 22 , N 23 and N 24 are output respectively, the drive signal G 11 , G 14 , G 24 and G 24 are connected with Q 11 , Q 14 , Q 24 and Q 24 respectively, and the drive signal G 11 , G 14 , G 24 and G 24 are output respectively. 31 , N 32 , N 33 and N 34 of the transformer T output the drive signal G 12 , G 13 , G 22 and G 23 respectively, the drive signal G 12 , G 13 , G 22 and G 23 are connected with Q 12 , Q 13 , Q 22 and Q 23 respectively, and the drive signal G A , G B and G C are output respectively.

[0012] The drive circuit comprises an input stage, an intermediate stage and an output stage; the input stage is connected with the voltage node 5V and DGND through the power supply end, the intermediate stage is connected with the voltage node T5V and TGND through the direct current power supply end, the intermediate stage is connected with the voltage node vp+ and vp- through the alternating current power supply end, and the output stage is connected with any j-way drive signal required by the isolated power supply V j , which is obtained through the transformer Tdj , rectifier bridge D dj and isolated power supply V j are connected.

[0013] comprising the following steps: 1-1: by adding a diode D between the positive pole of the high-voltage DC bus and the input end of the DC solid-state relay, to prevent damage to the controller when the positive and negative poles of the external high-voltage DC bus are reversed; 1-2: when powered on, first, the resistors R A1 and R A2 in the DC solid-state relay charge the capacitors C u and C d to suppress the inrush current during power-on, by connecting resistors R A1 and R A2 in parallel across the power tubes Q A1 and Q A2 in the DC solid-state relay, so that Q A1 and Q A2 sustain approximately equal voltages, and then, when the output voltage of the DC solid-state relay is charged to approximately the input voltage of the DC solid-state relay, Q A1 and Q A2 are closed; 1-3: by designing a high-voltage input isolation power supply in the auxiliary power supply, converting 800V-1200V high-voltage DC input to isolated 40V-60V low-voltage DC; 1-4: for the drive circuit, the input stage, intermediate stage and output stage use magnetic isolation, by connecting the intermediate stage DC power supply end TGND to the voltage node N, to reduce the requirement of the drive circuit for isolation voltage level; 1-5: the AC excitation power supply and each bridge arm of the three-phase full-bridge use three-level bridge arm circuit and control, to ensure that the two series-connected power tubes sustain approximately equal voltages, and to ensure that the AC excitation power supply and the three-phase full-bridge can withstand 800V-1200V high-voltage DC power supply; 1-6: during the starting process, the controller drives a two-stage starter to drag the engine from static to ignition speed, the AC excitation power supply provides AC excitation current to the exciter, and the three-phase full-bridge provides three-phase current to the main motor; 1-7: by the structural design of the controller, the electromagnetic interference of the high-voltage power circuit on the drive circuit and the control circuit is suppressed.

[0014] The high-voltage input isolation power supply design comprises the following steps: 2-1: by using the LLC full-bridge 1 and LLC full-bridge 2 primary series and secondary parallel circuit structure, the input voltages of LLC full-bridge 1 and LLC full-bridge 2 are approximately equal; 2-2: When Q2 is off, the voltage V c >18V, Q2 is on, when Q2 is on, the voltage Vc <12V, Q2 is off; 2-3: Slow charging of capacitor C1 is realized through resistor R1, when the voltage V c >18V, Q2 is on, the double-path PWM circuit is powered, the main circuit of the power supply enters the normal working state, the auxiliary winding N3 in LLC full-bridge 1 and LLC full-bridge 2 works and outputs the power supply V s to realize self-power supply of the double-path PWM circuit; 2-4: By reasonably selecting the capacity of capacitor C1, the energy stored in capacitor C1 from 18V to 12V is enough to support the double-path PWM circuit to enter the state of being powered by the power supply Vs; The three-level bridge arm circuit, any k path, k = x or y, x = A, B or C, y = 1 or 2, three-level bridge arm control, including the following steps: Relative to Q kuo , Q kui is turned on first and then turned off; Relative to Q kuo , Q kui is turned on first and then turned off; The structure design of the controller includes the following steps: 3-1: The power circuit including an AC excitation power supply and a three-phase full bridge is fixed on a metal heat sink, and the capacitive conduction coupling of the common mode voltage is weakened by adding an insulating layer between the metal heat sink and the metal shell; 3-2: The radiation coupling of the electric field is weakened by adding a metal shielding plate 1 between the drive circuit board on which the drive circuit is placed and the power circuit, and the conductivity and airtightness of the metal shielding plate 1 and the metal shell are ensured as much as possible; 3-3: The radiation coupling of the electric field is weakened by adding a metal shielding plate 2 between the control circuit board on which the control circuit is placed and the drive circuit board, and the conductivity and airtightness of the metal shielding plate 2 and the metal shell are ensured as much as possible; 3-4: The metal shell is arranged from bottom to top in the order of insulating layer, metal heat sink, power circuit, metal shielding plate 1, drive circuit board, metal shielding plate 2 and control circuit board.

[0015] Compared with the prior art, the beneficial effects of the present application are: The two-stage starter system and the design method are suitable for the field of 1kV high-voltage DC power supply and starting of the power engine of the electric propulsion aircraft, compared with the air starting mode of the engine, the auxiliary power device is saved, compared with the electric starting based on the brush DC motor, the deficiencies that the high voltage is not suitable and the clutch is difficult to meet the need of large torque application are overcome, compared with the electric starting based on the brushless permanent magnet motor, the deficiency that the clutch is difficult to meet the need of small torque application is overcome, in the DC solid-state relay, by connecting the resistors in parallel at the two ends of the series power tube, the power-on impact current is suppressed, and the voltage equalization of the series power tube is realized, for each bridge arm in the three-phase full-bridge and the AC excitation power supply, by adopting the three-level bridge arm circuit and control, the voltage equalization of the series power tube is realized, and the high voltage resistance is significantly enhanced compared with the two-level bridge arm.

[0016] In the application, for the high-voltage input isolation power supply in the auxiliary power supply, two groups of LLC full-bridge adopt the circuit structure of primary series and secondary parallel, which ensures the primary voltage equalization of the two groups of LLC full-bridge; through the hysteresis comparison circuit control of slow charging and fast discharging of the capacitor, self-power supply of the auxiliary winding, the starting control of the high-voltage input isolation power supply is realized, the power supply reliability of the power supply driving circuit is ensured, the use of high-power resistor is avoided, the power density is significantly improved, by connecting the middle stage DC power supply end of the driving circuit with the midpoint of the input high-voltage DC power supply, the isolation voltage level requirements of the input stage and the middle stage and the middle stage and the output stage are reduced, by adding an insulation layer between the metal heat sink and the metal shell of the power circuit to weaken the capacitive conduction coupling of the common mode voltage, by adding a metal shield between the power circuit, the driving circuit and the control circuit to weaken the radiation coupling of the electric field, the electromagnetic interference of the high-voltage power circuit on the driving circuit and the control circuit is suppressed. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The device structure diagram of the two-stage starter system for the electric propulsion aircraft power engine is provided in the application; Figure 2 The structure schematic diagram of the DC solid-state relay is provided in the application; Figure 3 The structure schematic diagram of the three-phase full-bridge is provided in the application; Figure 4 The schematic diagram of the AC excitation power supply is provided in the application; Figure 5 The schematic diagram of the auxiliary power supply is provided in the application; Figure 6 The schematic diagram of the high-voltage input isolation power supply is provided in the application; Figure 7 The schematic diagram of the driving circuit is provided in the application; Figure 8 The main motor control principle diagram is provided in the application; Figure 9Timing diagram for three-level bridge arm driving of the present application; Figure 10 Serial power tube voltage sharing principle for bridge arm current output of the present application; Figure 11 Serial power tube voltage sharing principle for bridge arm current input of the present application; Figure 12 Controller structure schematic diagram of the present application. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application. EMBODIMENT

[0019] The electric propulsion aircraft adopts a high-voltage DC bus with a rated voltage of 1kV, and the voltage fluctuation range is 800V-1200V. The engine is started through a two-stage starter system, and after the engine works normally, a high-power generator is used to generate electric energy required for driving the fan. The power supply for the two-stage starter system during starting is 8000-1200V high-voltage DC, and the starting characteristics are: 60N·m (0-3000r / min), 18kW (3000r / min-6000 / min). The engine rotational inertia is 0.85kg / m2.

[0020] As Figure 1 The two-stage starter system device for the power supply engine of the electric propulsion aircraft comprises a two-stage starter and a controller. The two-stage starter comprises an exciter, a rotating rectifier, a main motor and a rotating transformer. The controller comprises a diode D, a DC solid-state relay, a three-phase full bridge, an AC excitation power supply, an auxiliary power supply, a driving circuit, a control circuit, a capacitor C u and C d The stator excitation winding F+ and F- of the exciter are respectively connected with the output * and ~ of the AC excitation power supply, the A, B and C ends of the stator armature winding of the main motor are respectively connected with the A, B and C ends of the output of the three-phase full bridge, the output speed position signal P of the rotating transformer is connected with the control circuit, the negative pole of the high-voltage DC bus is respectively connected with the input negative pole of the auxiliary power supply, the input negative pole of the AC excitation power supply and the input negative pole of the three-phase full bridge, the positive pole of the high-voltage DC bus is respectively connected with the input positive pole of the auxiliary power supply and the input end of the DC solid-state relay through the anode of the diode D and the cathode of the diode D, the output end of the DC solid-state relay is respectively connected with the input negative pole of the AC excitation power supply and the input negative pole of the three-phase full bridge, and the output end of the DC solid-state relay is connected with the input negative pole of the AC excitation power supply and the input negative pole of the three-phase full bridge through the capacitor C u , the voltage node N and the capacitor Cd The high-voltage direct-current bus negative pole is connected, the voltage node N is connected with the alternating excitation power input N end and the three-phase full-bridge input N end respectively, the auxiliary power output is connected with the control circuit power supply end and the driving circuit power supply end respectively, the control circuit is connected with the driving circuit, the driving circuit output driving signal G A , G B and G C are connected with the direct-current solid-state relay, the three-phase full-bridge and the alternating excitation power respectively, the alternating excitation power output excitation current signal iF is connected with the control circuit, the three-phase full-bridge output three-phase current signal i ABC is connected with the control circuit to constitute.

[0021] The anti-reverse diode D is used to prevent the positive and negative poles of the output 1kV power supply from being connected reversely, and is realized by a diode in series connection with two power tubes in reverse parallel connection in a WGM100B1-1170GS6EN module of Weiguang 877 Factory, the single power tube of the module has a withstand voltage of 1700V and a rated current of 100A. The neutral point N is connected with the positive and negative bus to support the capacitors C u and C d which are realized by 5 12μF capacitors in parallel connection, the capacitors are MKP3D-1200V12μF-K-P37.5 of Hongda, with a withstand voltage of 1200V and a capacity of 12μF.

[0022] Figure 2 As shown in the figure, the direct-current solid-state relay comprises power tubes Q A1 and Q A2 , resistors R A1 and R A2 ; the input end of the direct-current solid-state relay is connected with the emitter C of Q A1 , the collector E of Q A1 is connected with the emitter C of Q A2 , the collector E of Q A2 is connected with the output end of the direct-current solid-state relay, the resistors RA1 are respectively connected with the emitter C and the collector E of Q A1 , the resistors R A2 are respectively connected with the emitter C and the collector E of Q A2 to constitute.

[0023] The direct-current solid-state relay is used to disconnect the starting controller from the power supply in case of failure. It is realized by a WGM100B1-1170GS6EN module of Weiguang 877 Factory.

[0024] Figure 3 As shown in the figure, the three-phase full-bridge comprises A, B and C phase bridge arms, and current sensors S A , S B and S CFor any x-phase bridge arm, x = A, B, or C, including power transistor Q... xuo Q xui Q xdi Q xdo diode D xu and D xd For any phase x, it is formed by the positive input of the three-phase full-bridge and Q. xuo The collector C is connected, Q xuo The emitter E is respectively with Q xui collectors C and D xu The cathode is connected, and the emitter E of Qxui is connected to Q. xdi The collector C is connected to the output x terminal of the three-phase full-bridge, Q xdi The emitter E is respectively with Q xdo collectors C and D xd Anode connection, Q xdo The emitter E is connected to the negative input of the three-phase full-bridge, and the N-terminal input of the three-phase full-bridge is connected to D. xu anode and D xd Cathode connection, current sensor S x Detect the current at the x-terminal output of the three-phase full-bridge bridge, and output the current signal i. x It is connected to the control circuit.

[0025] Figure 4 As shown, the AC excitation power supply includes bridge arms 1 and 2, and a current sensor S. F For any bridge arm y, y = 1 or 2, including power transistor Q yuo Q yui Q ydi Q ydo diode D yu and D yd For any bridge arm y, it is connected to the positive input terminal of the AC excitation power supply and Q. yuo The collector C is connected, Q yuo The emitter E is respectively with Q yui collectors C and D yu Cathode connection, Q yui The emitter E is respectively with Q ydi The collector C is connected, Q ydi The emitter E is respectively with Q ydo The collector C and the anode of Dyd are connected, Q ydo The emitter E of the electrode is connected to the negative input terminal of the AC excitation power supply. The input N terminal of the AC excitation power supply is connected to the anode of Dyu and the cathode of Dyd, respectively. The output * terminal of the AC excitation power supply is connected to Q. 1ui The collector E is connected, and the output terminal of the AC excitation power supply is connected to Q. 2ui The collector E is connected to the current sensor S.F The output end current of the AC excitation power supply is detected, and an excitation current signal iF is connected with the control circuit.

[0026] The three-phase full bridge and the bridge arm of the AC excitation power supply are realized by using three-level modules, and the modules are selected from WGM150C2170GB of Weiguang 877 Factory, with a withstand voltage of 1700V and a rated current of 150A.

[0027] Figure 5 The auxiliary power supply includes a high-voltage input isolation power supply, an 18V-75V input isolation power supply, a 12V isolation power supply, a 5V power supply, an AC power supply and a 5V isolation power supply. The positive and negative poles of the auxiliary power supply input are connected with the input positive and negative poles of the high-voltage input isolation power supply, respectively. The output positive and negative poles of the high-voltage input isolation power supply are connected with the input positive and negative poles of the 18V-75V input isolation power supply, respectively. The output positive and negative poles of the 18V-75V input isolation power supply are connected with the input positive and negative poles of the 5V isolation power supply and the 12V isolation power supply, respectively. The output positive and negative poles of the 5V isolation power supply are connected with the voltage nodes 5V and DGND, respectively. The output positive and negative poles of the 12V isolation power supply are connected with the voltage nodes T12V and TGND, respectively. The voltage nodes T12V and TGND are connected with the input positive and negative poles of the 5V power supply and the AC power supply, respectively. The output positive and negative poles of the 5V power supply are connected with the voltage nodes T5V and TGND, respectively. The two AC output ends of the AC power supply are connected with the voltage nodes vp+ and vp-, respectively.

[0028] Figure 6 As shown, the high-voltage input isolation power supply includes a power supply main circuit and a power supply driving circuit. The power supply main circuit includes capacitors C au and C ad , LLC full bridges 1 and 2, and for any LLC full bridge z, z=1 or 2, includes power tubes Q z1 ~Q z4 , diodes D z1 ~D z5 , capacitors C z1 ~C z3 , and transformers T z1 . The power supply driving circuit includes a hysteresis comparison circuit, resistors R1 and R2, a capacitor C1, a 15V voltage stabilizing tube Z1, an NPN triode Q1, a P-gate MOS tube Q2, a two-way PWM circuit, and a transformer T. For the power supply main circuit part, the input positive and negative poles of the high-voltage input isolation power supply are connected with the input positive and negative poles of the power supply main circuit, respectively. The output positive and negative poles of the high-voltage input isolation power supply are connected with the input positive and negative poles of the power supply main circuit, respectively. The input positive pole of the power supply main circuit is connected with the capacitor C au , the voltage node N a , and the capacitor C adThe LLC full-bridge 1 is connected to the negative input of the main power supply circuit. The positive and negative inputs of LLC full-bridge 1 are connected to the positive input of the main power supply circuit and voltage node Na, respectively. The positive and negative inputs of LLC full-bridge 2 are connected to the voltage node Na and negative input of the main power supply circuit, respectively. The positive and negative outputs of the main power supply are connected to the positive and negative outputs of LLC full-bridge 1 and LLC full-bridge 2, respectively. For any LLC full-bridge z, the positive input of LLC full-bridge z is connected to Q... z1 and Q z3 The collector C is connected, and the negative input of the LLC full-bridge z is connected to Q respectively. z2 and Q z4 The emitter E is connected, Q z1 The emitters E and Q z2 The collector C is connected, Q z3 The emitters E and Q z4 The collector C is connected, Q z1 The emitter E passes through capacitor C z1 Inductor L z1 Transformer T z1 The primary windings N1 and Q z3 The emitter E is connected, and the transformer T is connected. z1 One end of the secondary winding N2 is connected to D z1 anode and D z2 Cathode connection, transformer T z1 The other end of the secondary winding N2 is connected to D z3 anode and D z4 The cathode connection is such that the positive output of the LLC full-bridge z is connected to D. z1 cathode and D z3 The cathode connection is such that the negative output of the LLC full-bridge z is connected to D. z2 anode and D z4 The anode connection, capacitor C z2 The two ends are connected to the positive and negative output terminals of the LLC full-bridge circuit, respectively, and the transformer T... z1 One end of the auxiliary winding N3 is connected to D z5 anode, D z5 Cathode, voltage node V s Capacitor C z3 respectively with T z1 The other end of the auxiliary winding N3 is connected to the negative input terminal of the main power supply circuit; for the power drive circuit section, the positive input terminal of the high-voltage input isolation power supply is connected to the voltage node V via resistor R1. c Capacitor C1 is connected to the negative input terminal of the high-voltage input isolation power supply. The negative input terminal of the high-voltage input isolation power supply is connected to the anode of Z1 and the negative power supply terminal GND of the dual-channel PWM circuit, respectively. Voltage node V cThe source S of Q2, the drain D of Q2 and the positive supply V of the double PWM circuit are connected cc Connection, V c The gate G of Q2 is connected with the hysteresis comparison circuit, and the voltage node V s The collector C of Q1, the emitter E of Q1 and the positive supply V of the double PWM circuit are connected cc Connection, voltage node V s The base B of Q1 and the cathode of Z1 are connected with the resistance R2 respectively, and the two ends of the primary winding N1 of the transformer T are connected with the drive output G A and G B of the double PWM circuit respectively, the same phase winding N 21 , N 22 , N 23 and N 24 of the transformer T output drive signals G 11 , G 14 , G 24 and G 24 respectively, and the drive signals G 11 , G 14 , G 24 and G 24 are connected with Q 11 , Q 14 , Q 24 and Q 24 respectively. 31 , N 32 , N 33 and N 34 of the transformer T output drive signals G 12 , G 13 , G 22 and G 23 respectively, and the drive signals G 12 , G 13 , G 22 and G 23 are connected with Q 12 , Q 13 , Q 22 and Q 23 respectively.

[0029] The power tubes Q z1 ~Q z4 of the two groups of LLC full-bridge are selected from YBTD25Z17S9 of Yongguang Factory, with a withstand voltage of 1700V and a rated current of 25A. When the leakage inductance of the transformer T z1 meets the LLC resonance requirements, there is no need to add an inductor L z1 separately.

[0030] Figure 7As shown, the driving circuit includes an input stage, an intermediate stage and an output stage; the input stage is connected with the voltage node 5V and DGND through a power supply end, the intermediate stage is connected with the voltage node T5V and TGND through a direct current power supply end, the intermediate stage is connected with the voltage node vp+ and vp- through an alternating current power supply end, and the output stage is driven by the signal G A , G B and G C . The isolated power supply V j needed by any j-way driving signal is connected with the isolated power supply V dj through the transformer T dj , the rectifier bridge D j and the isolated power supply V A1 .

[0031] The design method of the two-stage starter system for the power supply engine of the electric propulsion aircraft, characterized in that it comprises the following steps: 1-1: By adding a diode D between the positive pole of the high-voltage direct current bus and the input end of the direct current solid-state relay, the damage to the controller caused by the reverse connection of the positive and negative poles of the external high-voltage direct current bus is prevented; 1-2: When powered on, first, the resistors R A1 and R A2 in the direct current solid-state relay are used to charge the capacitors C u and C d , so as to suppress the power-on inrush current, the resistors R A1 and R A2 are connected in parallel across the power tubes Q A1 and Q A2 in the direct current solid-state relay respectively, so that the voltage borne by Q A1 and Q A2 is approximately equal, and then when the output end voltage of the direct current solid-state relay is charged to be close to the input end voltage of the direct current solid-state relay, Q A1 and Q A2 are closed; 1-3: By designing a high-voltage input isolated power supply in the auxiliary power supply, the 800V-1200V high-voltage direct current input is converted into an isolated 40V-60V low-voltage direct current; 1-4: For the driving circuit, the input stage, the intermediate stage and the output stage adopt magnetic isolation, the driving circuit is connected with the voltage node N through the direct current power supply end TGND of the intermediate stage, so that the requirement of the driving circuit for the isolated voltage level is reduced; 1-5: The three-level bridge arm circuit and control are adopted for each bridge arm of the alternating current excitation power supply and the three-phase full-bridge, so as to ensure that the voltage borne by the two series-connected power tubes is approximately equal, and to ensure that the alternating current excitation power supply and the three-phase full-bridge can bear 800V-1200V high-voltage direct current power supply; 1-6: During the starting process, the controller drives the two-stage starter motor to pull the engine from standstill to ignition speed, provides AC excitation current to the exciter through AC excitation power supply, and provides three-phase current to the main motor through three-phase full bridge; 1-7: Through the structural design of the controller, electromagnetic interference from the high-voltage power circuit to the drive circuit and control circuit is suppressed; In the DC solid-state relay described in steps 1-2, the inrush current is suppressed by connecting a resistor in parallel across the series power transistor, while simultaneously achieving voltage equalization of the series power transistor. In steps 1-4, by connecting the intermediate stage DC power supply terminal of the drive circuit to the midpoint of the input high-voltage DC power supply, the isolation voltage requirements between the input stage and the intermediate stage, and between the intermediate stage and the output stage, are reduced. Isolation between the input stage and the intermediate stage is achieved using the Zhongke Geliwei GL1400 magnetic coupling isolation chip, and isolation between the intermediate stage and the output stage is achieved using the Zhongke Geliwei GLd1200 isolation driver chip.

[0032] Regarding the three-phase full-bridge supply of three-phase current to the main motor described in steps 1-6, combined with... Figure 8 The principle is explained below. The motor's position angle θ and rotational speed n are obtained through a rotary transformer, and then... ref (n) The control reference iq* for the active current is obtained from the relation table, and the control reference id* for the reactive current is preset. The active current iq and reactive current id are obtained by detecting the currents in phases A and B, and then by Clarke and Park transformations. The PI regulators of the active and reactive current loops are used, followed by an inverse Park transformation, to obtain the SVPWM control signals uα and uβ. SVPWM is applied to the three-phase full-bridge to form a closed-loop control. This ensures that the active current iq tracks the reference iq*, and the reactive current id tracks the reference id*, achieving startup control.

[0033] The high-voltage input isolation power supply design includes the following steps: 2-1: By adopting a circuit structure in which the primary windings of LLC full-bridge 1 and LLC full-bridge 2 are connected in series and the secondary windings are connected in parallel, the input voltages that LLC full-bridge 1 and LLC full-bridge 2 withstand are approximately equal. 2-2: When Q2 is turned off, the hysteresis comparator circuit requires a voltage V. c Q2 needs a voltage of >18V to turn on, and Q2 needs a voltage of <12V to turn off when Q2 is on. 2-3: Capacitor C1 is slowly charged through resistor R1. When voltage V... c When the voltage is >18V, Q2 conducts, supplying power to the dual-path PWM circuit. The main power supply circuit enters normal operation, and the auxiliary winding N3 in LLC full-bridge 1 and LLC full-bridge 2 outputs power V after it starts working. s To achieve self-powering of the dual-channel PWM circuit; 2-4: By reasonably selecting the capacity of capacitor C1, the energy stored in capacitor C1 from 18V to 12V is enough to support the double-path PWM circuit to enter the state powered by power supply Vs; Due to the fault, step 2-3 cannot be completed, and the charging and discharging process of capacitor C1 will be repeated continuously in the self-starting power supply described in step 2-3. However, the design adopts a slow capacitor charging energy storage and fast discharging power supply design, so the charging and discharging process of the capacitor can be repeated for a long time and will not cause the expansion of the fault. For the high-voltage input isolation power supply in the auxiliary power supply, the primary series and secondary parallel circuit structure of the two groups of LLC full-bridge ensures the primary voltage balance of the two groups of LLC full-bridge. Through the hysteresis comparison circuit to control the slow charging and fast discharging of the capacitor, the self-power supply of the auxiliary winding, the start-up control of the high-voltage input isolation power supply is realized, which ensures the power supply reliability of the power supply driving circuit and avoids the use of high-power resistors, so that the power density is significantly improved.

[0034] The three-level bridge arm circuit in any k-way, k = x or y, x = A, B or C, y = 1 or 2, its three-level bridge arm control includes the following steps: Relative to Q kuo , Q kui is first turned on and then turned off; Relative to Q kuo , Q kui is first turned on and then turned off; For the three-level bridge arm circuit and control described in step 1-5, in combination with Figures 9-11 its principle is described. Figure 9 The three-level bridge arm drive timing diagram is shown. Assuming that the theoretical upper and lower tube drives Q ku and Q kd are generated by the control circuit, both are complementary conduction states; then Q kui is first turned on and then turned off relative to Q kuo , Q kdi is first turned on and then turned off relative to Q kdo . Q kui is realized by delaying the rising edge of Qku by 2△T and delaying the falling edge by △T, Q kuo is realized by delaying the rising edge of Q ku by 3△T and ensuring continuous synchronization of the falling edge. Q kd generates Q kdi and Q kdo , and the principle of generating Q ku and Q kui by Q kuo is the same, and △T = 2.5μs in this embodiment.

[0035] In Figure 10(b) When power transistor Q kui is turned on, the emitter voltage of Q ku is clamped to the voltage of midpoint N due to the clamping of diode D kuo , so that the voltage borne by power transistor Q kuo is only half of the DC bus voltage. In Figure 10 (c) When power transistors Q kuo and Q kui are turned on simultaneously, the emitter voltage of Q kd will not be lower than the voltage of midpoint N due to the clamping of diode D kdo , so that the voltage borne by power transistor Q kdo is only half of the DC bus voltage or less; in order to prevent overvoltage of power transistor Q kdi , a resistor is needed to be connected in parallel between the collector and the emitter of power transistor Q kdi , so that diode D kdi will clamp the voltage of the emitter of power transistor Q kdi to the voltage of midpoint N, so that the voltage of the emitter of power transistor Q kdi will not be lower than the voltage of midpoint N.

[0036] In Figure 11 (f) When power transistor Q kdi is turned on, the collector voltage of Q kd is clamped to the voltage of midpoint N due to the clamping of diode D kdo , so that the voltage borne by power transistor Q kdo is only half of the DC bus voltage. In Figure 11 (g) When power transistors Q kdo and Q kdi are turned on simultaneously, the emitter voltage of Q kuo will not be lower than the voltage of midpoint N due to the clamping of diode Dku, so that the voltage borne by power transistor Q kuo is only half of the DC bus voltage or less; in order to prevent overvoltage of power transistor Q kui , a resistor is needed to be connected in parallel between the collector and the emitter of power transistor Q kui , so that diode D ku will clamp the voltage of the emitter of power transistor Q kui to the voltage of midpoint N, so that the voltage of the collector of power transistor Q kui will not be lower than the voltage of midpoint N.

[0037] According to the above theoretical analysis, as long as the power transistor switching control is performed according to the timing sequence shown in Figure 9 , and a resistor with a large resistance value is connected in parallel beside power transistors Q kui and Q kdi , the voltage borne by the series-connected power transistors can be ensured to be only half of the DC bus voltage.

[0038] For each bridge arm in three-phase full-bridge and AC excitation power supply, by using three-level bridge arm circuit and control, the voltage equalization of series power tube is realized, and the high voltage resistance is significantly enhanced compared with two-level bridge arm.

[0039] In combination Figure 12 The structure design of the controller comprises the following steps: 3-1: The power circuit comprising AC excitation power supply and three-phase full-bridge is fixed on a metal heat sink, and the capacitive conduction coupling of common mode voltage is weakened by adding an insulating layer between the metal heat sink and the metal shell; 3-2: The radiation coupling of electric field is weakened by adding a metal shielding plate 1 between the drive circuit board on which the drive circuit is placed and the power circuit, and the conductivity and airtightness of the metal shielding plate 1 lapped with the metal shell are ensured as much as possible; 3-3: The radiation coupling of electric field is weakened by adding a metal shielding plate 2 between the control circuit board on which the control circuit is placed and the drive circuit board, and the conductivity and airtightness of the metal shielding plate 2 lapped with the metal shell are ensured as much as possible; The capacitive conduction coupling of common mode voltage is weakened by adding an insulating layer between the metal heat sink of the power circuit and the metal shell, and the radiation coupling of electric field is weakened by adding a metal shielding plate between the power circuit, the drive circuit and the control circuit, so that the electromagnetic interference of the high-voltage power circuit on the drive circuit and the control circuit is inhibited.

[0040] The two-stage starter system and the design method are suitable for the field of 1kV high-voltage DC power supply and starting of the power engine of the electric propulsion aircraft. Compared with the air starting mode of the engine, the auxiliary power device is saved. Compared with the electric starting based on the brush DC motor, the deficiencies of unsuitable high voltage and difficult clutch to meet the need of large torque application are overcome. Compared with the electric starting based on the brushless permanent magnet motor, the deficiency of difficult clutch to meet the need of small torque application is overcome.

[0041] The basic principles, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only preferred examples of the present application and are not intended to limit the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A two-stage starter system for an electric propulsion aircraft engine, characterized in that, The system includes a two-stage starter and a controller. The two-stage starter comprises an exciter, a rotating rectifier, a main motor, and a rotary transformer. The controller includes a diode D, a DC solid-state relay, a three-phase full-bridge converter, an AC excitation power supply, an auxiliary power supply, a drive circuit, a control circuit, and a capacitor C. u and C d The system consists of: the stator excitation windings F+ and F- terminals of the exciter connected to the AC excitation power supply output terminals * and ~ respectively; the stator armature windings A, B, and C terminals of the main motor connected to the three-phase full-bridge output terminals A, B, and C respectively; the speed and position signal P output from the rotary transformer connected to the control circuit; the negative terminal of the high-voltage DC bus connected to the negative input terminals of the auxiliary power supply, the AC excitation power supply, and the three-phase full-bridge input respectively; the positive terminal of the high-voltage DC bus connected to the positive input terminal of the auxiliary power supply and the input terminal of the DC solid-state relay via the anode and cathode of diode D respectively; the output terminal of the DC solid-state relay connected to the negative input terminals of the AC excitation power supply and the three-phase full-bridge input respectively; and the output terminal of the DC solid-state relay connected to capacitor C. u Voltage node N and capacitor C d Connected to the negative terminal of the high-voltage DC bus, voltage node N is connected to both the AC excitation power input N terminal and the three-phase full-bridge input N terminal. The auxiliary power output is connected to both the control circuit power supply terminal and the drive circuit power supply terminal. The control circuit is connected to the drive circuit, and the drive circuit outputs the drive signal G. A G B and G C It is connected to a DC solid-state relay, a three-phase full-bridge circuit, and an AC excitation power supply, respectively. The AC excitation power supply outputs an excitation current signal iF, which is connected to the control circuit. The three-phase full-bridge circuit outputs a three-phase current signal i. ABC It is connected to the control circuit.

2. The two-stage starter system for an electric propulsion aircraft engine according to claim 1, characterized in that, The DC solid-state relay includes a power transistor Q. A1 and Q A2 Resistance R A1 and R A2 It is formed by the input terminal of a DC solid-state relay and Q. A1 The emitter C is connected, Q A1 collectors E and Q A2 The emitter C is connected, Q A2 The collector E is connected to the output terminal of the DC solid-state relay, and the two ends of the resistor RA1 are connected to Q respectively. A1 The emitter C and collector E are connected, and the resistor R A2 Both ends are respectively connected to Q A2 The emitter C and collector E are connected together.

3. The two-stage starter system for an electric propulsion aircraft engine according to claim 1, characterized in that, The three-phase full bridge includes phases A, B, and C, and a current sensor S. A S B and S C For any x-phase bridge arm, x = A, B, or C, including power transistor Q... xuo Q xui Q xdi Q xdo diode D xu and D xd For any phase x, it is formed by the positive input of the three-phase full-bridge and Q. xuo The collector C is connected, Q xuo The emitter E is respectively with Q xui collectors C and D xu The cathode is connected, and the emitter E of Qxui is connected to Q. xdi The collector C is connected to the output x terminal of the three-phase full-bridge, Q xdi The emitter E is respectively with Q xdo collectors C and D xd Anode connection, Q xdo The emitter E is connected to the negative input of the three-phase full-bridge, and the N-terminal input of the three-phase full-bridge is connected to D. xu anode and D xd Cathode connection, current sensor S x Detect the current at the x-terminal output of the three-phase full-bridge bridge, and output the current signal i. x It is connected to the control circuit.

4. The two-stage starter system for an electric propulsion aircraft engine according to claim 1, characterized in that, The AC excitation power supply includes bridge arms 1 and 2, and a current sensor S. F For any bridge arm y, y = 1 or 2, including power transistor Q yuo Q yui Q ydi Q ydo diode D yu and D yd For any bridge arm y, it is connected to the positive input terminal of the AC excitation power supply and Q. yuo The collector C is connected, Q yuo The emitter E is respectively with Q yui collectors C and D yu Cathode connection, Q yui The emitter E is respectively with Q ydi The collector C is connected, Q ydi The emitter E is respectively with Q ydo The collector C and the anode of Dyd are connected, Q ydo The emitter E of the electrode is connected to the negative input terminal of the AC excitation power supply. The input N terminal of the AC excitation power supply is connected to the anode of Dyu and the cathode of Dyd, respectively. The output * terminal of the AC excitation power supply is connected to Q. 1ui The collector E is connected, and the output terminal of the AC excitation power supply is connected to Q. 2ui The collector E is connected to the current sensor S. F The system detects the output current at the * terminal of the AC excitation power supply, and the output excitation current signal iF is connected to the control circuit.

5. The two-stage starter system for an electric propulsion aircraft power supply engine according to claim 1, characterized in that, The auxiliary power supply includes a high-voltage input isolation power supply, an 18V-75V input isolation power supply, a 12V isolation power supply, a 5V power supply, an AC power supply, and a 5V isolation power supply. It is configured by connecting the positive and negative input terminals of the auxiliary power supply to the positive and negative input terminals of the high-voltage input isolation power supply, respectively; connecting the positive and negative output terminals of the high-voltage input isolation power supply to the positive and negative input terminals of the 18V-75V input isolation power supply, respectively; connecting the positive and negative output terminals of the 18V-75V input isolation power supply to the positive and negative input terminals of the 5V and 12V isolation power supplies, respectively; connecting the positive and negative output terminals of the 5V isolation power supply to voltage nodes 5V and DGND, respectively; connecting the positive and negative output terminals of the 12V isolation power supply to voltage nodes T12V and TGND, respectively; connecting voltage nodes T12V and TGND to the positive and negative input terminals of the 5V and AC power supplies, respectively; connecting the positive and negative output terminals of the 5V power supply to voltage nodes T5V and TGND, respectively; and connecting the two AC output terminals of the AC power supply to voltage nodes vp+ and vp-, respectively.

6. The two-stage starter system for an electric propulsion aircraft power supply engine according to claim 5, characterized in that, The high-voltage input isolation power supply includes a main power supply circuit and a power supply drive circuit. The main power supply circuit includes a capacitor C. au and C ad LLC full-bridge 1, LLC full-bridge 2, for any LLC full-bridge z, z=1 or 2, including power transistor Q z1 ~Q z4 diode D z1 ~D z5 Capacitor C z1 ~C z3 Transformer T z1 The power supply drive circuit includes a hysteresis comparator circuit, resistors R1 and R2, capacitor C1, a 15V Zener diode Z1, an NPN transistor Q1, a P-channel MOSFET Q2, a dual-channel PWM circuit, and a transformer T. For the main power supply circuit, the positive and negative input terminals of the high-voltage input isolation power supply are connected to the positive and negative input terminals of the main power supply circuit, respectively. The positive and negative output terminals of the high-voltage input isolation power supply are also connected to the positive and negative input terminals of the main power supply circuit, respectively. The positive input terminal of the main power supply circuit is connected to the capacitor C. au Voltage node N a Capacitor C ad The LLC full-bridge 1 is connected to the negative input of the main power supply circuit. The positive and negative inputs of LLC full-bridge 1 are connected to the positive input of the main power supply circuit and voltage node Na, respectively. The positive and negative inputs of LLC full-bridge 2 are connected to the voltage node Na and negative input of the main power supply circuit, respectively. The positive and negative outputs of the main power supply are connected to the positive and negative outputs of LLC full-bridge 1 and LLC full-bridge 2, respectively. For any LLC full-bridge z, the positive input of LLC full-bridge z is connected to Q... z1 and Q z3 The collector C is connected, and the negative input of the LLC full-bridge z is connected to Q respectively. z2 and Q z4 The emitter E is connected, Q z1 The emitters E and Q z2 The collector C is connected, Q z3 The emitters E and Q z4 The collector C is connected, Q z1 The emitter E passes through capacitor C z1 Inductor L z1 Transformer T z1 The primary windings N1 and Q z3 The emitter E is connected, and the transformer T is connected. z1 One end of the secondary winding N2 is connected to D z1 anode and D z2 Cathode connection, transformer T z1 The other end of the secondary winding N2 is connected to D z3 anode and D z4 The cathode connection is such that the positive output of the LLC full-bridge z is connected to D. z1 cathode and D z3 The cathode connection is such that the negative output of the LLC full-bridge z is connected to D. z2 anode and D z4 The anode connection, capacitor C z2 The two ends are connected to the positive and negative output terminals of the LLC full-bridge circuit, respectively, and the transformer T... z1 One end of the auxiliary winding N3 is connected to D z5 anode, D z5 Cathode, voltage node V s Capacitor C z3 respectively with T z1 The other end of the auxiliary winding N3 is connected to the negative input terminal of the main power supply circuit; for the power drive circuit section, the positive input terminal of the high-voltage input isolation power supply is connected to the voltage node V via resistor R1. c Capacitor C1 is connected to the negative input terminal of the high-voltage input isolation power supply. The negative input terminal of the high-voltage input isolation power supply is connected to the anode of Z1 and the negative power supply terminal GND of the dual-channel PWM circuit, respectively. Voltage node V c The source (S) and drain (D) of Q2 are connected to the positive power supply V of the dual-channel PWM circuit. cc Connection, V c The voltage node V is connected to the gate G of Q2 via a hysteresis comparator circuit. s The collector C and emitter E of Q1 are connected to the positive power supply V of the dual-path PWM circuit. cc Connection, voltage node V s Resistor R2 is connected to the base B of Q1 and the cathode of Z1 respectively. The two ends of the primary winding N1 of transformer T are connected to the drive output G of the dual-channel PWM circuit respectively. A and G B Terminal connection, the in-phase winding N of transformer T 21 N 22 N 23 and N 24 Output drive signal G respectively 11 G 14 G 24 and G 24 Drive signal G 11 G 14 G 24 and G 24 respectively with Q 11 Q 14 Q 24 and Q 24 Connection, the reverse winding N of transformer T 31 N 32 N 33 and N 34 Output drive signal G respectively 12 G 13 G 22 and G 23 Drive signal G 12 G 13 G 22 and G 23 respectively with Q 12 Q 13 Q 22 and Q 23 Connection constitutes.

7. The two-stage starter system for an electric propulsion aircraft power supply engine according to any one of claims 1 and 4, characterized in that, The driving circuit includes an input stage, an intermediate stage, and an output stage. The input stage's power supply terminal is connected to voltage nodes 5V and DGND; the intermediate stage's DC power supply terminal is connected to voltage nodes T5V and TGND; and the intermediate stage's AC power supply terminal is connected to voltage nodes vp+ and vp-. The output stage driving signal G... A G B and G C The required isolation power supply V for any j-channel drive signal j It is formed by the AC power supply terminals vp+ and vp- through transformer T dj 1. Rectifier bridge D dj With isolated power supply V j Connection constitutes.

8. The design method of a two-stage starter system for an electric propulsion aircraft engine according to any one of claims 1-7, characterized in that, Includes the following steps: 1-1: By adding diode D between the positive terminal of the high-voltage DC bus and the input terminal of the DC solid-state relay, damage to the controller can be prevented when the positive and negative terminals of the external high-voltage DC bus are reversed. 1-2: Upon power-up, firstly, the resistor R in the DC solid-state relay... A1 and R A2 To give capacitor C u and C d Charging is used to suppress the inrush current during power-on, which is achieved by using the power transistor Q in the DC solid-state relay. A1 and Q A2 Resistors R are connected in parallel at both ends. A1 and R A2 , making Q A1 and Q A2 The voltages are roughly equal. Then, when the voltage at the output terminal of the DC solid-state relay is charged to be close to that at the input terminal, Q is closed. A1 and Q A2 ; 1-3: Through the design of the high-voltage input isolation power supply in the auxiliary power supply, the 800V~1200V high-voltage DC input is converted into an isolated 40V~60V low-voltage DC; 1-4: For the drive circuit, the input stage, intermediate stage and output stage are magnetically isolated. By connecting the DC power supply terminal TGND of the intermediate stage to the voltage node N, the requirement of the isolation voltage level of the drive circuit is reduced. 1-5: The AC excitation power supply and each arm of the three-phase full bridge adopt a three-level bridge arm circuit and control to ensure that the voltage of the two series power transistors is roughly equal, and to ensure that the AC excitation power supply and the three-phase full bridge can withstand high-voltage DC power supply of 800V to 1200V. 1-6: During the starting process, the controller drives the two-stage starter motor to pull the engine from standstill to ignition speed, provides AC excitation current to the exciter through AC excitation power supply, and provides three-phase current to the main motor through three-phase full bridge; 1-7: Through the structural design of the controller, electromagnetic interference from the high-voltage power circuit to the drive circuit and control circuit is suppressed.

9. The design method of a two-stage starter system for an electric propulsion aircraft power supply engine according to claim 8, characterized in that, The high-voltage input isolation power supply design includes the following steps: 2-1: By adopting a circuit structure in which the primary windings of LLC full-bridge 1 and LLC full-bridge 2 are connected in series and the secondary windings are connected in parallel, the input voltages that LLC full-bridge 1 and LLC full-bridge 2 withstand are approximately equal. 2-2: When Q2 is turned off, the hysteresis comparator circuit requires a voltage V. c Q2 needs a voltage of >18V to turn on, and Q2 needs a voltage of <12V to turn off when Q2 is on. 2-3: Capacitor C1 is slowly charged through resistor R1. When voltage V... c When the voltage is >18V, Q2 conducts, supplying power to the dual-path PWM circuit. The main power supply circuit enters normal operation, and the auxiliary winding N3 in LLC full-bridge 1 and LLC full-bridge 2 outputs power V after it starts working. s To achieve self-powered operation of the dual-channel PWM circuit; 2-4: By reasonably selecting the capacitance of capacitor C1, the energy stored in capacitor C1 when it decreases from 18V to 12V is sufficient to support the dual-path PWM circuit to enter the state powered by power supply Vs; In the three-level bridge arm circuit, for any k channels, k = x or y, x = A, B, or C, and y = 1 or 2, the three-level bridge arm control includes the following steps: Compared to Q kuo Q kui Turn on first, then turn off; Compared to Q kuo Q kui Turn on first, then turn off; The structural design of the controller includes the following steps: 3-1: The power circuit, including the AC excitation power supply and the three-phase full bridge, is fixed on the metal heat sink. The capacitive conduction coupling of the common mode voltage is weakened by adding an insulating layer between the metal heat sink and the metal casing. 3-2: By adding a metal shielding plate 1 between the drive circuit board where the drive circuit is placed and the power circuit, the radiation coupling of the electric field is weakened, and the conductivity and airtightness of the metal shielding plate 1 and the metal shell are ensured as much as possible. 3-3: By adding a metal shielding plate 2 between the control circuit board and the drive circuit board where the control circuit is placed, the radiation coupling of the electric field is weakened, and the conductivity and airtightness of the metal shielding plate 2 and the metal shell are ensured as much as possible. 3-4: The internal structure of the metal casing, from bottom to top, consists of the insulation layer, metal heat sink, power circuit, metal shielding plate 1, drive circuit board, metal shielding plate 2, and control circuit board.

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