A three-stage generator power supply system and design method for aviation low-voltage DC

Abstract

A three-stage generator power supply system and design method for aviation low-voltage DC, the system includes a three-stage starter generator and a starter generator controller, the three-stage starter generator includes a permanent magnet auxiliary exciter, a main exciter, a rotating rectifier tube, a main motor, and a resolver, the starter generator controller includes a MOS tube three-phase full bridge, an AC excitation power supply, a voltage regulator, an auxiliary power supply, a control circuit, a current sensor S F and S dc When starting, the starting process is operated in the maximum torque current ratio mode, driving the three-stage starter generator from standstill to the engine ignition speed. When generating electricity, the voltage regulator outputs the excitation current to adjust the main motor output three-phase AC voltage value to achieve the DC voltage V dc Voltage stabilization control; through the MOS tube three-phase full bridge to achieve the main motor output three-phase AC voltage v M To DC voltage V dc The synchronous rectification, on the other hand, realizes the voltage V dc Boost control when voltage is too low.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic circuits, and in particular relates to a three-stage generator power supply system for aviation low-voltage direct current and a design method thereof. Background Art

[0002] Manned aircraft have high reliability requirements. Motors must be able to demagnetize after a fault occurs to prevent it from spreading. They must also have an overload capacity of 1.5 times the rated current for 5 minutes and 2 times the rated current for 5 seconds during normal power generation and regulated output. They must also be able to output 3 times the short-circuit current and have minimal high-frequency ripple. For manned aircraft under 12kW, 28V low-voltage DC is typically used to power onboard equipment.

[0003] The three-stage starter-generator power supply system consists of a three-stage starter-generator and a starter-generator controller. The three-stage starter-generator is used to convert mechanical energy into variable-voltage and variable-frequency AC power. During the starting phase, the starter-generator controller provides AC excitation current to the starter-generator and converts the DC power provided by the starting power supply into variable-voltage and variable-frequency AC power to power the three-stage generator, driving the motor from a standstill to the engine ignition speed. During the generating phase, the starter-generator controller stabilizes the variable-frequency AC voltage output by the three-stage starter-generator by regulating the excitation current. This constant AC voltage is then converted into a regulated 28V DC voltage to power aircraft equipment.

[0004] Three-stage motors are commonly used in high-voltage power supply systems and generator power supply systems. However, the three-stage motor power supply system has the following shortcomings:

[0005] 1) It is widely used in high-voltage power supply systems, but is still less used in low-voltage DC power supply systems;

[0006] 2) It is widely used in generator power supply systems, and its application in starter generator power supply systems is still in the development stage.

[0007] Currently, brushless DC starter generators are widely used in low-voltage DC power systems. These systems offer high power density and simple control. However, they have the following drawbacks:

[0008] 1) The failure rate of the DC brush starter generator commutator is relatively high, especially in high-altitude operation environments;

[0009] 2) The carbon brushes of the DC brush starter generator have a short service life and need to be replaced regularly;

[0010] 3) During operation, the carbon dust dropped by the carbon brush will reduce the insulation performance of the motor.

[0011] Permanent magnet starter generator power supply systems are commonly used in the field of aviation UAVs. Permanent magnet starter generator systems have the advantages of simple motor design and high efficiency. However, permanent magnet starter generator power supply systems have the following shortcomings:

[0012] 1) The permanent magnet starter generator uses permanent magnet excitation. After a fault occurs, it is impossible to ensure the safety of the starter generator power system by demagnetizing it;

[0013] 2) During power generation, the permanent magnet starter generator cannot regulate the excitation current to stabilize the power generation voltage. The power density of the starter generator controller is low, and it is difficult to achieve a power generation capacity of more than 4kW.

[0014] 3) The power density of the permanent magnet starter generator power system has no significant advantage over the three-stage starter generator after considering the overload capacity of 1.5 times the rated current for 5 minutes and 2 times the rated current for 5 seconds.

[0015] 4) It is difficult for the permanent magnet starter generator power supply system to achieve a 3 times short-circuit current output capacity;

[0016] 5) When generating electricity, the starter generator controller needs to use high-frequency switching power supply technology to stabilize the power generation voltage. Although the output power ripple is small, the high-frequency ripple spectrum is difficult to meet the relevant standard requirements. Summary of the Invention

[0017] To solve the above technical problems, the present invention provides a three-stage generator power supply system for aviation low-voltage DC and a design method.

[0018] The present invention is achieved through the following technical solutions.

[0019] The present invention provides a three-stage generator power supply system for aviation low-voltage DC, including a three-stage starter generator and a starter generator controller. The three-stage starter generator includes a permanent magnet auxiliary exciter, a main exciter, a rotating rectifier tube, a main motor and a resolver; the starter generator controller includes a MOS tube three-phase full bridge, an AC excitation power supply, a voltage regulator, an auxiliary power supply, a control circuit, a current sensor S F With current sensor S dc The permanent magnet auxiliary excitation stator armature winding W PMG Output three-phase AC v PWM The A, B and C terminals are connected to the auxiliary power supply and the A, B and C input terminals of the voltage regulator respectively. The rotor armature winding W of the main exciter EM Output three-phase AC v EM Through the rotating rectifier and the main motor rotor excitation winding W ME Connection, stator excitation winding W of the main exciter EEThe F+ and F- terminals are connected to the AC excitation power supply output terminal and the voltage regulator output terminal, and the stator armature winding W of the main motor MM Three-phase ACv M The A, B and C terminals of the MOSFET are connected to the A, B and C terminals of the MOSFET three-phase full bridge respectively. The rotating stator output speed position signal P is connected to the control circuit. The DC bus Vdc The + and - ends of the MOSFET are connected to the DC bus V Adc + and - terminals, AC excitation power input V Bi The + and - ends of the output power input and the control circuit are connected, and the - end of the voltage regulator is connected to the DC bus V dc The - end of the MOS tube is connected to the three-phase AC current signal i ABC Connected to the control circuit, the control circuit outputs the driving signal G A Connected to the MOS tube three-phase full bridge, the control circuit outputs the drive signal G B and the switch control signal S B Connected to the AC excitation power supply, the control circuit outputs the drive signal G C and the switch control signal S C Connected to the voltage regulator, the two power outputs of the auxiliary power supply are V c1 、V c2 Connected to the control circuit, the auxiliary power supply outputs the current signal I D Connected to the control circuit, the power enable signal E output by the control circuit n Connect to the auxiliary power supply, current sensor S dc The power terminal, output signal I dc Respectively with the DC bus V dc + terminal, control circuit connection, current sensor S F The power end and output signal iF are respectively connected to the excitation winding W EE The F+ terminal of the control circuit is connected.

[0020] Furthermore, the MOS tube three-phase full bridge includes an A-phase bridge arm, a B-phase bridge arm, a C-phase bridge arm, a filter capacitor C dc , current sensor S A1 、S A2 and S A3 , driving signal G A Including G A1 , G A2 , G A3 , G A4 , G A5 With G A6 , three-phase AC current i ABC Including i A 、i B and iC The A end of the MOS tube three-phase full bridge and the A phase bridge arm upper tube Q A1 The source and lower tube Q A2 The drain connection of the A phase bridge arm upper tube Q A1 The drain and DC bus V Adc The + end of the bridge arm of phase A is connected to the lower tube Q A2 The source S and the DC bus V Adc The - end of the MOS tube three-phase full bridge is connected to the B end of the B phase bridge arm upper tube Q A3 The source S and the lower tube Q A4 The drain D is connected to the B phase bridge arm upper tube Q A3 The drain and DC bus V Adc The + end of the B-phase bridge arm is connected to the lower tube Q A4 The source and DC bus V Adc The - end of the MOS tube three-phase full bridge is connected to the C end of the C phase bridge arm upper tube Q A5 The source and lower tube Q A6 The drain connection of the C phase bridge arm upper tube Q A5 The drain and DC bus V Adc The + end of the C-phase bridge arm is connected to the lower tube Q A6 The source and DC bus V Adc - end connection, filter capacitor C Adc The two ends are connected to the DC bus V Adc The + and - terminals of the current sensor S A1 、S A2 and S A3 The power end is connected to the A, B and C terminals respectively, and the current sensor S A1 、S A2 and S A3 Respectively with the output signal i A 、i B and i C Corresponding connection, the driving signal G A1 , G A2 , G A3 , G A4 , G A5 and G A6 Respectively with Q A1 , Q A2 , Q A3 , Q A4 , Q A5 and Q A6 corresponding gate connections.

[0021] Furthermore, the AC excitation power supply includes a diode D B1 , multiple boost DC / DC modules, filter capacitor C B , power tube QB1 , Q B2 , Q B3 and Q B4 , relay SCR, drive signal G B Including G B1 , G B2 , G B3 and G B4 ; is input by V Bi The + terminal of the diode D B1 The anode of the diode D B1 The cathodes are connected to the + terminals of multiple step-up DC / DC modules, and the input V Bi The - end of the boost DC / DC module is connected to the - end of the input of the boost DC / DC module, and the + and - ends of the output of the boost DC / DC module are connected to the DC bus V s Connect the + and - terminals of the Bi - end and DC bus V s - end connection, filter capacitor C B The two ends are respectively DC bus V s The + and - ends are connected, Q B1 The drain and DC bus V s The + end of the relay SCR is connected; the relay SCR has two switches, the input end of the first switch is connected to the Q B1 the source and Q B2 The drain connection, Q B2 The source and DC bus V s - end connection, Q B3 The drain and DC bus V s The + end of the relay SCR is connected to the input of the second switch Q B3 The source S and Q B4 The drain connection, Q B4 The source and DC bus V s - end is connected, the output end of the switch in the relay SCR is connected to the output v Bo Connection, drive signal G B1 , G B2 , G B3 and G B4 Respectively with Q B1 , Q B2 , Q B3 and Q B4 The gate connection, switch control signal S B Connect to the control terminal of relay SCR.

[0022] Furthermore, the voltage regulator includes a diode D C1 、D C2 、D C3 、D C4 、DC5 、D C6 and D C7 , power tube Q C1 , Q C2 and Q C3 , filter capacitor C C , relay GCR, drive signal G C Including G C1 ~G C3 ;A terminal and D terminal of the voltage regulator C1 Anode and D C2 The cathode of the regulator is connected to the B terminal of the D C3 Anode and D C4 The cathode of the regulator is connected to the C terminal of the D C5 Anode and D C6 Cathode connection; D C1 、D C3 and D C5 The cathode and DC bus V G The + end connection, D C2 、D C4 and D C6 The anode and DC bus V G - end connection, filter capacitor C C The two ends are respectively DC bus V G The + and - ends are connected, Q C1 The drain and DC bus V G The + end of the relay GCR is connected to the input of the first switch and Q C1 the source and Q C2 The drain connection, Q C2 The source and DC bus V G - end connection, D C7 The cathode and DC bus V G The + end of the relay GCR is connected to the input end of the second switch of D C7 Anode and Q C3 The drain connection, Q C3 The source and DC bus V G - end of the relay GCR is connected to the output v Co The + and - terminals are connected, and the driving signal G C1 , G C2 and G C3 Respectively with Q C1 , Q C2 and Q C3 The gate connection, switch control signal S C Connect to the control terminal of relay SCR.

[0023] Furthermore, the auxiliary power supply includes a diode D D1、D D2 、D D3 and D D4 , non-isolated DC / DC module, first isolated DC / DC module, second isolated DC / DC module, current sensor S D ; The + terminal of the auxiliary power supply and D D1 Anode connection, D D1 The cathode is connected to the + terminal of the non-isolated DC / DC module output, D D2 、D D3 and D D4 The anode is connected to terminals A, B and C respectively, and D D2 、D D3 and D D4 The cathode is connected to the + end of the non-isolated DC / DC module input, the - end of the auxiliary power supply is connected to the - end of the non-isolated DC / DC module input, the - end of the non-isolated DC / DC module output, the - end of the first isolated DC / DC module output, and the - end of the second isolated DC / DC module output, and the + end and - end of the non-isolated DC / DC module output are respectively connected to the + end and - end of the first isolated DC / DC module input, and the + end and - end of the second isolated DC / DC module input; and also includes two power supplies, the + end and - end of the first isolated DC / DC module output are connected to the first power supply V c1 The + and - ends of the second isolated DC / DC module are connected to the + and - ends of the second power supply V c2 The + and - terminals of the current sensor S D The power terminal and the second power supply V c2 The + terminal of the current sensor S D Output signal I D , power enable signal E n Connected to the enable terminal E of the second isolated DC / DC module input.

[0024] A design method for a three-stage generator power supply system for aviation low-voltage DC includes the following steps:

[0025] Step 1: Let the rated current be I N , ensuring that the three-stage starter generator can output 1.5I under the conditions of minimum generating speed and voltage regulation N ; Step 2: Ensure that the output voltage of the three-stage starter generator does not exceed 45V when the load current switches from 150% to 20% at the highest generating speed; Step 3: Assume that the average inductance of the main motor armature winding L = (L d +L q ) / 2, inductive reactance X at the highest generating speed max =ω max L, make 1.5I N X max<35V; Step 4: Assume that the inductive reactance of the armature winding of the main exciter at the lowest generating speed is X emin , the resistance of the main motor excitation winding at the highest operating temperature is R emax , guarantee X emin / R emax >0.5; Step 5: Assume the inductance of the main motor excitation winding is L e , the resistance at the lowest operating temperature is R emin , ensure time is always L e / R emin <50ms; Step 6: Under the condition of generator speed range and voltage regulator load from no load to maximum load, ensure that the rectified output voltage V of the permanent magnet auxiliary excitation in the three-stage starter generator is G In the range of 12V to 45V; Step 7: Assume that the frequency of the AC excitation power supply is f, and the maximum effective value of the AC excitation current of the main exciter during startup is I Fmax , the excitation inductance of the main exciter is L ee , so that 130V < 2πfL ee I Fmax <170V; Step 8: The resolver stator outputs a speed position signal P including a speed signal n and a position signal θ, wherein the position signal θ=0° corresponds to the zero-crossing point of the voltage drop section of the main motor A phase under no-load conditions; Step 9: For the DC bus V G The capacitor C C， Ensure that all energy in the main excitation winding is fed back to the capacitor C C When the capacitor C C The voltage on the control circuit is still within the allowable range; Step 10: Power the control circuit through the auxiliary power supply, power supply V c2 Used to power the power tube drive circuit in the control circuit. The power supply V c1 Used to power other circuits in the control circuit. If the power supply V c2 The output current I D When abnormal, the power enable signal E n The isolated DC / DC module 2 in the isolated power supply is prohibited from working; Step 11: During the starting process, the starter generator controller drives the three-stage starter generator from rest to the engine ignition speed; Step 12: After the engine reaches the power generation speed, it enters the power generation process. When the power generation speed and load change, the voltage regulator and MOS tube three-phase full bridge control stabilize the output DC voltage V dc .

[0026] Furthermore, the starting process in step 11 includes the following steps:

[0027] Step 1101: Output a switch control signal S via a control circuit B and S C, turn on the relay SCR switch and turn off the relay GCR switch; Step 1102: Use the boost DC / DC modules 1, 2...n in the AC excitation power supply to increase the 28V input voltage V Bi Converted to 270V voltage V s , by connecting multiple boost DC / DC modules in parallel to increase the output power; Step 1103: by the AC excitation power supply from Q B1 ~Q B4 The single-phase H-bridge provided by the control circuit provides AC excitation current to the main exciter; Step 1104: The control circuit adopts the control strategy of quasi-speed outer loop and current inner loop, and generates the driving signal G of the MOS tube three-phase full bridge through sinusoidal space vector pulse width modulation SVPWM control. A , so that the starting process works in the maximum torque current ratio mode.

[0028] Furthermore, the power generation process in step 12 includes the following steps:

[0029] Step 1201: Output a switch control signal S via a control circuit B and S C , disconnect the relay SCR switch and connect the relay GCR switch; Step 1202: adjust the output three-phase AC voltage value of the main motor through the voltage regulator output excitation current, thereby achieving the DC voltage V dc Voltage stabilization control; Step 1203: Use the MOS tube three-phase full bridge to realize the main motor output three-phase AC voltage v M To DC voltage V dc The synchronous rectification, on the other hand, realizes the voltage V dc Boost control when voltage is too low.

[0030] Furthermore, the voltage stabilization control in step 1202 includes the following steps:

[0031] Step 12021: Generate a drive signal G for the voltage regulator in the control circuit C1 , by adopting dual-loop control to generate power tube Q C1 The driving signal G C1 In the dual-loop control, the voltage loop is the outer loop, the excitation current loop is the inner loop, and the voltage outer loop is used to make the output voltage V dc Tracking parameter voltage V ref , and generates the current inner loop reference signal I fref The inner current loop is used to make the main exciter excitation current i F Tracking reference signal I fref The current inner loop output is used to control the power tube Q C1 Drive signal G C1 Duty cycle D; Step 12022: According to the output DC current I dc, determine the voltage outer loop reference voltage V ref , assuming the rated current is I N , in I dc <2I N When V ref =28V, at I dc By 2I N to 3I N When the V ref Reduce from 28V to 0V; Step 12023: Determine the maximum excitation current I allowed by the voltage loop output according to the input speed n fmax , I fmax For speed n, 1.5I N Under the condition of dc is the excitation current corresponding to the desired regulated voltage value; Step 12024: at the input voltage V dc <40V, the driving signal G C3 =1, power tube Q C3 Constant conduction, power tube Q C2 The driving signal G C2 With power tube Q C1 The driving signal G C1 Complementary conduction allows the freewheeling current to flow through the power tube Q C2 , not Q C2 The reverse parallel diode; Step 12025: At the input voltage V dc >40V, the driving signal G C1 ~G C3 are all equal to 0, the power tube Q C1 ~Q C3 Constant off, the excitation current of the main exciter passes through the power tube Q C2 The anti-parallel diode and diode D C7 , feeding energy back to the DC bus V G To achieve rapid demagnetization.

[0032] Furthermore, the boost control in step 1203 includes the following steps:

[0033] Step 12031: According to the three-phase current i A 、i B and i C , determine the driving signal G of synchronous rectification control A1G ~G A6G , define the three-phase current i A 、i B and i C The direction of outflow from the starter generator controller is positive, I refH and I refL They are +1 / 5 and -1 / 5 of the rated current respectively. When i A>I refH When G A2G =1, otherwise G A2G =0, when i B >I refH When G A4G =1, otherwise G A4G =0, when i C >I refH When G A6G =1, otherwise G A6G =0, when i A refL When G A1G =1, otherwise G A1G =0, when i B refL When G A3G =1, otherwise G A3G =0, when i C refL When G A5G =1, otherwise G A5G =0; Step 12032: According to the DC voltage V dc , DC current I dc , determine the driving signal G for boost voltage regulation control A1O ~G A6O , define the driving signal G A2O The falling edge lag θ=180° is δ1, and the driving signal G A2O The high level pulse width is δ2, when the DC voltage V dc <24V and I dc <2I N When the active current i is increased by increasing the width of δ2 q Make the DC voltage stable at 24V, and adjust δ1 to make the reactive current i d =0, reducing δ1 corresponds to reducing the demagnetization reactive current i d , the adjustment range of δ1 is 0~60°, the adjustment range of δ2 is 0~90°, G A1O ~G A6O With the same positive pulse width, press G A2O , G A5O , G A4O , G A1O , G A6O , G A3O The boost voltage control drive signal G is formed in a 60° phase difference. A1O ~G A6O ; Step 12033: According to the driving signal G controlled by synchronous rectification A1G ~G A6G And the boost voltage control drive signal G A1O ~G​​​A6O , determine the MOS tube three-phase full-bridge drive signal G A ,

[0034] The beneficial effects of the present invention are as follows: 1. The proposed design method for a three-stage starter-generator power supply system for aviation low-voltage DC is suitable for manned aircraft with high reliability requirements. Compared with a brushless DC starter-generator power supply system, the three-stage starter-generator power supply system has higher reliability and is more convenient to maintain. Compared with a permanent magnet starter-generator power supply system, the three-stage starter-generator power supply system can be demagnetized in the event of a fault, thus providing higher safety.

[0035] 2. The common main exciter excitation winding is used during starting and generating. Compared with the method of using independent three-phase AC excitation winding during starting, the motor power density is higher;

[0036] 3. A boost DC / DC module is used in the AC excitation power supply to increase the starting power supply voltage from 28V to 270V, solving the compatibility issue of the main exciter excitation winding used during starting and power generation.

[0037] 4. Both the inverter during starting and the rectifier during power generation are implemented using MOS tube three-phase full-bridge, achieving hardware reuse for starting and power generation, overcoming the shortcoming of traditional starters that become dead weight on the aircraft after completing the starting task;

[0038] 5. By adopting SVPWM control with maximum torque-current ratio, the capacity requirement of the starting power supply is effectively reduced;

[0039] 6. When generating electricity, the digital dual-loop control of voltage outer loop and current inner loop is adopted. Compared with the combination of analog single voltage loop and current soft feedback control, the control accuracy is higher and the control parameter setting is easier;

[0040] 7. During power generation, as the output current I dc The voltage loop input parameter voltage V changes from 2 times the rated current to 3 times the rated current. ref Reducing from 28V to 0V can effectively suppress the maximum voltage during load shedding;

[0041] 8. When generating electricity, the voltage loop outputs the maximum allowable excitation current I fmax The excitation current value is limited to the operating speed n and 1.5 times the rated current, which can effectively suppress the maximum voltage during load rejection;

[0042] 9. When the voltage regulator is working normally, the freewheeling tube Q C2 Working in synchronous rectification mode, the efficiency is significantly improved compared to the diode freewheeling mode;

[0043] 10. The voltage regulator adopts an asymmetric half-bridge structure instead of the traditional Buck circuit. When the output is overvoltage, the voltage regulator can disconnect the power tube Q C3 The method can realize rapid demagnetization and faster response speed;

[0044] 11. During power generation, the MOS tube three-phase full-bridge works in synchronous rectification mode. Compared with the diode three-phase full-bridge rectification, the power tube conduction voltage drop is significantly reduced and the efficiency is significantly improved;

[0045] 12. By adopting MOS tube boost voltage regulation control, the dynamic characteristics of the three-stage starter generator system can be improved, and the maximum voltage during load rejection can be effectively suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a structural block diagram of the three-stage starter generator power supply system of the present invention;

[0047] Figure 2 This is the MOS tube three-phase full-bridge circuit diagram of the present invention;

[0048] Figure 3 The AC excitation power supply circuit diagram of the present invention;

[0049] Figure 4 is a circuit diagram of a voltage regulator of the present invention;

[0050] Figure 5 is the auxiliary power supply circuit diagram of the present invention;

[0051] Figure 6 This is a schematic diagram of the starting control principle of the present invention;

[0052] Figure 7 This is a working principle diagram of the voltage regulator of the present invention;

[0053] Figure 8 Schematic diagram of the working principle of the asymmetric half-bridge in the voltage regulator of the present invention;

[0054] Figure 9 This is a schematic diagram of the synchronous rectification drive signal generation principle of the MOS tube three-phase full bridge of the present invention;

[0055] Figure 10 This is a schematic diagram of the driving signal generation principle for the boost and voltage stabilization control of the MOS tube three-phase full bridge of the present invention;

[0056] Figure 11 This is a vector diagram of the uncontrolled rectification control and controlled rectification control of the present invention. DETAILED DESCRIPTION

[0057] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0058] This embodiment is a 6kW three-stage starter-generator power supply system, which includes a three-stage starter-generator and a starter-generator controller. When the three-stage starter-generator system is started, the starting power supply is 28V DC, and the starting torque is 25N·m (0-1000r / min) and 10N·m (1000-6000r / min). When the generator is running, the output is 28VDC, the output power is 6kW (7500r / min-13000r / min), and it has an overload capacity of 150% rated load for 5min and 200% rated load for 5s; and a short-circuit capacity of an output current of not less than 300% rated current within 5s. The application background of the embodiment is an aerial drone using a turboprop engine, and the airborne equipment uses a 28V LVDC power supply system.

[0059] Figure 1 The figure shows a MOS tube three-phase full-bridge circuit diagram, a three-stage starter generator power supply system device for aviation low-voltage DC, including a three-stage starter generator and a starter generator controller. The three-stage starter generator includes a permanent magnet auxiliary exciter, a main exciter, a rotating rectifier tube, a main motor, and a resolver. The starter generator controller includes a MOS tube three-phase full-bridge, an AC excitation power supply, a voltage regulator, an auxiliary power supply, a control circuit, and a current sensor S. F and S dc ; It is composed of permanent magnet auxiliary excitation stator armature winding W PMG Output three-phase AC v PWM The A, B and C terminals of the main exciter are connected to the A, B and C input terminals of the auxiliary power supply and the voltage regulator respectively. EM Output three-phase AC v EM Through the rotating rectifier and the main motor rotor excitation winding W ME Connection, stator excitation winding W of the main exciter EE The F+ and F- terminals are connected to the AC excitation power supply output v Bo The * and ~ ends of the voltage regulator output V Co The + and - terminals of the main motor are connected to the stator armature winding W MM Three-phase ACv M The A, B and C terminals of the MOSFET are connected to the A, B and C terminals of the MOSFET three-phase full bridge respectively. The rotating stator output speed position signal P is connected to the control circuit. The DC bus V dc The + and - ends of the MOSFET are connected to the DC bus V Adc + and - terminals, AC excitation power input V Bi The + and - ends of the output power supply, the + and - ends of the output power supply, and the control circuit are connected, and the - end of the voltage regulator is connected to the DC bus V dc The - end of the MOS tube is connected to the three-phase AC current signal i ABCConnected to the control circuit, the control circuit outputs the driving signal G A Connected to the MOS tube three-phase full bridge, the control circuit outputs the drive signal G B and the switch control signal S B Connected to the AC excitation power supply, the control circuit outputs the drive signal G C and the switch control signal S C Connected to the voltage regulator, the two power outputs of the auxiliary power supply are V c1 、V c2 Connected to the control circuit, the auxiliary power supply outputs the current signal I D Connected to the control circuit, the power enable signal E output by the control circuit n Connect to the auxiliary power supply, current sensor S dc The power terminal, output signal I dc Respectively with the DC bus V dc + terminal, control circuit connection, current sensor S F The power end, output signal i F Respectively with the excitation winding W EE The F+ terminal and the control circuit are connected.

[0060] Current sensor S F The current sensor S is implemented using Allegro's ACS730KLCTR-40AB-T, which has a range of -40A to +40A. dc The HC5F800-S from LEM is used to implement the measurement, with a range of -800A to +800A. The control circuit adopts a DSP+FPGA structure, with the DSP using the TMS320F28335PGFA from TI and the FPGA using the EP3C25E114CN from Altera.

[0061] A common main exciter excitation winding is used during both starting and generating. Compared with the method of using independent three-phase AC excitation windings during starting, the motor power density is higher.

[0062] Figure 2 The MOS tube three-phase full bridge includes an A-phase bridge arm, a B-phase bridge arm, a C-phase bridge arm, and a filter capacitor C dc , current sensor S A1 、S A2 and S A3 , driving signal G A Including G A1 ~G A6 , three-phase AC current i ABC Including i A 、i B and i C ; It is connected by the A end and the A phase bridge arm upper tube QA1 The source S and the lower tube Q A2 The drain D is connected to the A phase bridge arm upper tube Q A1 The drain D and the DC bus V Adc The + end of the bridge arm of phase A is connected to the lower tube Q A2 The source S and the DC bus V Adc The - end is connected to the B end and the B end is connected to the upper tube Q of the B phase bridge arm. A3 The source S and the lower tube Q A4 The drain D is connected to the B phase bridge arm upper tube Q A3 The drain D and the DC bus V Adc The + end of the bridge arm of phase B is connected to the lower tube Q A4 The source S and the DC bus V Adc The - end is connected to the C end and the C phase bridge arm upper tube Q A5 The source S and the lower tube Q A6 The drain D is connected to the C phase bridge arm upper tube Q A5 The drain D and the DC bus V Adc The + end of the C-phase bridge arm is connected to the lower tube Q A6 The source S and the DC bus V Adc - end connection, filter capacitor C Adc The two ends are connected to the DC bus V Adc The + and - terminals of the current sensor S A1 、S A2 and S A3 The power end is connected to the A, B and C terminals respectively, and the current sensor S A1 、S A2 and S A3 Output signal i A 、i B and i C , driving signal G A1 ~G A6 Respectively with Q A1 ~Q A6 The gate G connection.

[0063] The A-phase, B-phase and C-phase bridge arms respectively use the MOS tube module MMN1000DB010B from MACMIC. It can withstand a maximum current of 1000A and an on-resistance of R on =1.7mΩ(150℃), withstand voltage 100V. Filter capacitor C Adc 100 Zhuzhou Hongda ceramic capacitors CT45-T-X5R-100V-107M are connected in parallel, with a single capacitor having a withstand voltage of 100V and a capacitance of 100μF. A1 、S A2 and S A3It is implemented using LEM's HC5F800-S, which has a range of -800A to +800A.

[0064] The inverter during starting and the rectifier during power generation are both implemented using MOS tube three-phase full-bridge, achieving hardware reuse in starting and power generation states, overcoming the shortcoming of traditional starters that become dead weight of the aircraft after completing the starting task.

[0065] Figure 3 The AC excitation power supply circuit diagram is shown. The AC excitation power supply includes a diode D B1 , step-up DC / DC modules 1, 2...n, filter capacitor C B , power tube Q B1 ~Q B4 , relay SCR, drive signal G B Including G B1 ~G B4 ; is input by V Bi The + terminal of the diode D B1 The anode of the diode D B1 The cathode of the boost DC / DC module is connected to the + terminal of the boost DC / DC module 1, 2...n, and the input V Bi The - end of the boost DC / DC module 1, 2...n is connected to the - end of the input, and the + and - ends of the output of the boost DC / DC module 1, 2...n are connected to the DC bus V s Connect the + and - terminals of the Bi - end and DC bus V s - end connection, filter capacitor C B The two ends are respectively DC bus V s The + and - ends are connected, Q B1 The drain D and the DC bus V s The + end of the relay SCR is connected to the input terminal 1A of the first switch and Q B1 The source S and Q B2 The drain D is connected to Q B2 The source S and the DC bus V s - end connection, Q B3 The drain D and the DC bus V s The + end of the relay SCR is connected to the input terminal 2A of the second switch and Q B3 The source S and Q B4 The drain D is connected to Q B4 The source S and the DC bus V s - end of the relay SCR, the output end 1Y of the first switch and the output end 2Y of the second switch are connected to the output v Bo The * end and the ~ end are connected, and the driving signal G B1 ~G B4 Respectively with QA1 ~Q A6 The gate G is connected to the switch control signal S B It is connected to the control end of the relay SCR.

[0066] The step-up DC / DC module uses Shenghua's SLBN28500H270SN, with three modules connected in parallel. A single SLBN28500H270SN module allows for a regulated input voltage range of 16 to 40 VDC, can withstand a 100 ms, 55 V transient, and delivers an output voltage of 270 V at 500 W. The SLBN28500H270SN measures 60.6 × 63.1 × 13 mm and weighs 150 g. The relay SCRs are J400-J1N from AVIC 315 Factory. The power transistor Q B1 ~Q B4 Each power tube code corresponds to two Infineon MOS tubes IPT60R050G7 connected in parallel. The single IPT60R050G7 has a current rating of 57A and a withstand voltage of 650V.

[0067] The AC excitation power supply uses a step-up DC / DC module to increase the starting power supply voltage from 28V to 270V, solving the compatibility problem of the main exciter excitation winding used during starting and power generation.

[0068] Figure 4 The voltage regulator circuit diagram is shown. The voltage regulator includes a diode D C1 ~D C7 , power tube Q C1 ~Q C3 , filter capacitor C C , relay GCR, drive signal G C Including G C1 ~G C3 ; It is composed of A end and D C1 Anode and D C2 The cathode is connected to the B terminal and the D C3 Anode and D C4 The cathode is connected to the C terminal and the D C5 Anode and D C6 Cathode connection, D C1 、D C3 and D C5 The cathode and DC bus V G The + end connection, D C2 、D C4 and D C6 The anode and DC bus V G - end connection, filter capacitor C C The two ends are respectively DC bus V G The + and - ends are connected, Q C1The drain D and the DC bus V G The + end of the relay GCR is connected to the input terminal 1A of the first switch and Q C1 The source S and Q C2 The drain D is connected to Q C2 The source S and the DC bus V G - end connection, D C7 The cathode and DC bus V G The + end of the relay GCR is connected to the input terminal 2A of the second switch and D C7 Anode and Q C3 The drain D is connected to Q C3 The source S and the DC bus V G - end of the relay GCR, the output end 1Y of the first switch and the output end 2Y of the second switch are connected to the output v Co The + and - terminals are connected, and the driving signal G C1 ~G C3 Respectively with Q C1 ~Q C3 The gate G is connected to the switch control signal S C It is connected to the control end of the relay SCR.

[0069] Diode D C1 ~D C6 MBRB20200CT is selected, with a withstand voltage of 200V, a current of 20A, and a conduction voltage drop of 0.7V. Capacitor C C The ceramic capacitor CT45-T-X5R-100V-107M is used in parallel, with a withstand voltage of 100V and a single capacitance of 100μF. C1 ~Q C3 The automotive power tube IAUT300N10S5N015 from Infineon is selected, which has a withstand voltage of 100V, a current of 300A, and an on-resistance of 1.5mΩ. C7 The reverse parallel diode of the power tube IAUT300N10S5N015 is used. The relay GCR uses the 315 factory J400-J1N.

[0070] Figure 5 The auxiliary power supply circuit diagram is shown, and the auxiliary power supply includes a diode D D1 ~D D4 , non-isolated DC / DC module, isolated DC / DC module 1, isolated DC / DC module 2, current sensor S D ; is composed of + terminal and D D1 Anode connection, D D1 The cathode is connected to the + terminal of the non-isolated DC / DC module output, D D2 、D D3 and DD4 The anode is connected to terminals A, B and C respectively, and D D2 、D D3 and D D4 The cathode is connected to the + end of the non-isolated DC / DC module input, the - end is connected to the - end of the non-isolated DC / DC module input, the - end of the non-isolated DC / DC module output, the - end of the isolated DC / DC module 1 output, and the - end of the isolated DC / DC module 2 output. The + end and - end of the non-isolated DC / DC module output are respectively connected to the + end and - end of the isolated DC / DC module 1 input, and the + end and - end of the isolated DC / DC module 2 input. The + end and - end of the isolated DC / DC module 1 output are connected to the first power supply V c1 The + and - ends of the DC / DC module 2 are connected to isolate the + and - ends of the DC / DC module 2 output from the second power supply V c2 The + and - terminals of the current sensor S D The power terminal and power supply V c2 The + terminal of the current sensor S D Output signal I D , power enable signal E n It is connected to the enable terminal E of the isolated DC / DC module 2 input.

[0071] Diode D D1 ~D D4 MBRB20200CT is selected, with a withstand voltage of 200V, a current of 20A, and a conduction voltage drop of 0.7V. The non-isolated DC / DC module uses Sichuan Shenghua's NSL28U2K4H60SN, with an effective input voltage range of 9 to 60V and an output voltage of 30V. Isolated DC / DC module 1 and isolated DC / DC module 2 use Sichuan Shenghua's power modules SAY2410H05S and SD24100H12S to generate a 5V power supply V. c1 and 12V power supply V c2 . Current sensor S D It is implemented using Allegro's ACS724LLCTR-05AB-T, with a range of -5A to +5A.

[0072] A design method for a three-stage starter-generator power supply system for aviation low-voltage DC includes the following steps:

[0073] Step 1: Let the rated current be I N , ensuring that the three-stage starter generator can output 1.5I under the conditions of minimum generating speed and voltage regulation N ;

[0074] Step 2: Ensure that the output voltage of the three-stage starter generator does not exceed 45V when the load current is switched from 150% to 20% at the highest generating speed;

[0075] Step 3: Assume the average inductance of the main motor armature winding L = (L d +L q ) / 2, inductive reactance X at the highest generating speed max =ω max L, make 1.5I N X max <35V;

[0076] Step 4: Assume the inductive reactance of the main exciter armature winding at the lowest generating speed is X emin , the resistance of the main motor excitation winding at the highest operating temperature is R emax , guarantee X emin / R emax >0.5;

[0077] Step 5: Let the inductance of the main motor excitation winding be L e , the resistance at the lowest operating temperature is R emin , ensure time is always L e / R emin <50ms;

[0078] Step 6: Under the condition of the generator speed range and the voltage regulator load from no load to maximum load, ensure that the rectified output voltage V of the permanent magnet auxiliary excitation in the three-stage starter generator is G In the range of 12V~45V;

[0079] Step 7: Assume that the frequency of the AC excitation power supply is f, and the maximum effective value of the AC excitation current of the main exciter during startup is I Fmax , the excitation inductance of the main exciter is L ee , so that 130V < 2πfL ee I Fmax <170V;

[0080] Step 8: The resolver stator outputs a speed position signal P including a speed signal n and a position signal θ. The position signal θ=0° corresponds to the zero-crossing point of the voltage drop section of the main motor phase A under no-load conditions.

[0081] Step 9: For the DC bus V in the voltage regulator G The capacitor C C , ensuring that all energy in the main excitation winding is fed back to the capacitor C C When the capacitor C C The voltage on the MOSFET is still within the allowable range;

[0082] Step 10: Use the auxiliary power supply to power the control circuit. The power supply V c2 Used to power the power tube drive circuit in the control circuit. The power supply V c1 Used to power other circuits in the control circuit. If the power supply Vc2 The output current I D When abnormal, the power enable signal E n The isolated DC / DC module 2 in the isolated power supply is prohibited from operating;

[0083] Step 11: During the starting process, the starter generator controller drives the three-stage starter generator from rest to the engine ignition speed;

[0084] Step 12: After the engine reaches the power generation speed, it enters the power generation process. When the power generation speed and load change, the voltage regulator and MOS tube three-phase full bridge control stabilize the output DC voltage V dc .

[0085] Combine Figure 6 The starting control principle diagram shown in FIG. 1 illustrates the starting process control described in step 11, which includes the following steps:

[0086] Step 1101: Output a switch control signal S via a control circuit B and S C , turn on the relay SCR switch and turn off the relay GCR switch;

[0087] Step 1102: The 28V input voltage V is increased by the step-up DC / DC modules 1, 2, ... n in the AC excitation power supply. Bi Converted to 270V voltage V s , by connecting multiple boost DC / DC modules in parallel to increase output power;

[0088] Step 1103: Q in the AC excitation power supply B1 ~Q B4 The single-phase H-bridge provided by the circuit provides AC excitation current to the main exciter;

[0089] Step 1104: The control circuit adopts a quasi-speed outer loop and current inner loop control strategy, and generates a driving signal G for the MOS tube three-phase full bridge through sinusoidal space vector pulse width modulation (SVPWM) control. A , so that the starting process works in the maximum torque current ratio mode.

[0090] When using the maximum torque / current ratio control, i d with I ref The relationship between is shown in formula (1), i q The expression is shown in formula (2).

[0091]

[0092] Where, U0 is the effective value of the phase voltage under no-load.

[0093]

[0094] By adopting SVPWM control with maximum torque-to-current ratio, the capacity requirement of the starting power supply is effectively reduced.

[0095] The power generation process control described in step 12 includes the following steps:

[0096] Step 1201: Outputting switch control signals SB and SC via the control circuit to turn off the relay SCR switch and turn on the relay GCR switch;

[0097] Step 1202: Regulating the output three-phase AC voltage of the main motor by outputting an excitation current through the voltage regulator, thereby achieving voltage stabilization control of the DC voltage Vdc;

[0098] Step 1203: A three-phase full-bridge MOS tube is used to realize synchronous rectification of the three-phase AC voltage vM output by the main motor to the DC voltage Vdc, and to realize boost control when the voltage Vdc is too low.

[0099] Combine Figure 7 The working principle diagram of the voltage regulator is shown in the figure and Figure 8 The working principle diagram of the asymmetric half-bridge in the voltage regulator shown in FIG. 1 illustrates the voltage regulation control of the voltage regulator in step 1202 in step 12, which includes the following steps:

[0100] Step 12021: Generate a drive signal G for the voltage regulator in the control circuit C1 , by adopting dual-loop control to generate power tube Q C1 The driving signal G C1 In the dual-loop control, the voltage loop is the outer loop, the excitation current loop is the inner loop, and the voltage outer loop is used to make the output voltage V dc Tracking parameter voltage V ref , and generates the current inner loop reference signal I fref The inner current loop is used to make the main exciter excitation current i F Tracking reference signal I fref The current inner loop output is used to control the power tube Q C1 Drive signal G C1 Duty cycle D;

[0101] Step 12022: According to the output DC current I dc , determine the voltage outer loop reference voltage V ref , assuming the rated current is I N , in I dc <2I N When V ref =28V, at I dc By 2I N to 3I N When the Vref Reduce from 28V to 0V;

[0102] Step 12023: Determine the maximum excitation current I allowed by the voltage loop output based on the input speed n fmax , I fmax For speed n, 1.5I N Under the condition of dc is the excitation current corresponding to the desired regulated voltage value;

[0103] Step 12024: At the input voltage V dc <40V, the driving signal G C3 =1, power tube Q C3 Constant conduction, power tube Q C2 The driving signal G C2 With power tube Q C1 The driving signal G C1 Complementary conduction allows the freewheeling current to flow through the power tube Q C2 , not Q C2 The reverse parallel diode;

[0104] Step 12025: At the input voltage V dc >40V, the driving signal G C1 ~G C3 are all equal to 0, the power tube Q C1 ~Q C3 Constant off, the excitation current of the main exciter passes through the power tube Q C2 The anti-parallel diode and diode DC7 feed energy back to the DC bus V G To achieve rapid demagnetization.

[0105] The digital dual-loop control with voltage outer loop and current inner loop has higher control accuracy and easier control parameter adjustment than the combination of analog single voltage loop and current soft feedback control.

[0106] With the output current I dc The voltage loop input parameter voltage V changes from 2 times the rated current to 3 times the rated current. ref Reducing from 28V to 0V can effectively suppress the maximum voltage during load shedding.

[0107] The maximum excitation current I allowed by the voltage loop output fmax Limiting the excitation current value at the operating speed n and 1.5 times the rated current can effectively suppress the maximum voltage during load rejection.

[0108] When the voltage regulator is working normally, the freewheeling tube Q C2 Working in synchronous rectification mode, the efficiency is significantly improved compared to the diode freewheeling mode.

[0109] The voltage regulator uses an asymmetric half-bridge structure instead of the traditional Buck circuit. When the output is overvoltage, the voltage regulator can disconnect the power tube Q C3 way to achieve rapid demagnetization and faster response speed.

[0110] Combine Figure 9 The schematic diagram of the synchronous rectification drive signal generation of the MOS tube three-phase full bridge is shown in the figure and Figure 10 The schematic diagram of the boost stabilization control driving signal generation principle of the MOS tube three-phase full-bridge is shown, which illustrates the MOS tube three-phase full-bridge boost control described in step 1203 in step 12, including the following steps:

[0111] Step 12031: According to the three-phase current i A 、i B and i C , determine the driving signal G of synchronous rectification control A1G ~G A6G , define the three-phase current i A 、i B and i C The direction of outflow from the starter generator controller is positive, I refH and I refL They are +1 / 5 and -1 / 5 of the rated current respectively. When i A >I refH When G A2G =1, otherwise G A2G =0, when i B >I refH When G A4G =1, otherwise G A4G =0, when i C >I refH When G A6G =1, otherwise G A6G =0, when i A refL When G A1G =1, otherwise G A1G =0, when i B refL When G A3G =1, otherwise G A3G =0, when i C refL When G A5G =1, otherwise G A5G =0;

[0112] Step 12032: According to the DC voltage V dc , DC current I dc , determine the driving signal G for boost voltage regulation control A1O ~G A6O , define the driving signal G​​​A2O The falling edge lag θ=180° is δ1, and the driving signal G A2O The high level pulse width is δ2, when the DC voltage V dc <24V and I dc <2I N When the active current i is increased by increasing the width of δ2 q Make the DC voltage stable at 24V, and adjust δ1 to make the reactive current i d =0, reducing δ1 corresponds to reducing the demagnetization reactive current i d , the adjustment range of δ1 is 0~60°, the adjustment range of δ2 is 0~90°, G A1O ~G A6O With the same positive pulse width, press G A2O , G A5O , G A4O , G A1O , G A6O , G A3O The boost voltage control drive signal G is formed in a 60° phase difference. A1O ~G A6O ;

[0113] Step 12033: According to the driving signal G controlled by synchronous rectification A1G ~G A6G And the boost voltage control drive signal G A1O ~G A6O , determine the MOS tube three-phase full-bridge drive signal G A ,

[0114] During power generation, the MOS tube three-phase full-bridge operates in synchronous rectification mode. Compared with the diode three-phase full-bridge rectification, the power tube conduction voltage drop is significantly reduced and the efficiency is significantly improved.

[0115] Figure 11 The vector diagram of uncontrolled rectifier control and controlled rectifier control is shown in Figure 2. Figure 11 The uncontrolled rectifier phasor diagram explains the reasons for the output voltage overshoot. It is mainly caused by two reasons. On the one hand, the energy stored in the motor's main armature inductance is released to the bus. The armature winding inductance stores 1 / 2·LI s 2 This is the reason for the first voltage spike. On the other hand, in order to overcome the voltage drop on the armature winding inductance of the main motor under heavy load ( Figure 11 In the uncontrolled rectifier phasor diagram, I d1 X d and I q1 X q1 caused) and armature current Is1 Medium-weak magnetic current i d1 The back EMF drop caused by the component ( Figure 11 In the uncontrolled rectifier phasor diagram, I d1 X d caused by the increase of the excitation current, which makes the excitation current too high, and the corresponding back electromotive force under no-load is large (such as Figure 11 E in the uncontrolled rectifier phasor diagram 01 After the load is dumped, the voltage drop across the armature winding inductance of the main motor is significantly reduced, and the armature reaction that forms the weakening magnetic effect is also low. The excessive back EMF is directly transmitted to the output end. At the same time, due to the large electromechanical constant of the main motor, the excitation current of the main motor cannot be restored quickly; this is the reason for the second voltage spike.

[0116] When the boost voltage regulation control is adopted, combined with Figure 11 The controlled rectifier phasor diagram explains the principle of voltage stabilization. s Becomes Advanced U s , so that the current phasor I s2 and no-load back EMF 02 The phases are opposite. At this time, the armature current i s2 There is no weak magnetic component i d2 , output voltage amplitude |U s | is higher than the no-load back EMF amplitude |E 02 |, and the output voltage amplitude under uncontrolled rectification |U s | is lower than the no-load back EMF amplitude |E 01 |Compared to the same output voltage amplitude |U s |The corresponding no-load back electromotive force |E 02 |E is significantly smaller than that under uncontrolled rectification 01 |. At the same time, the phase current I s2 All components are active current components I q2 , and I under uncontrolled rectification q1 Equal, and there is no longer any power-free current component I during uncontrolled rectification d1 , so the amplitude of the armature winding current |I s2 | is also significantly lower than |I when no rectification is controlled s1 |.

[0117] For the first peak, due to Less than Therefore, the first peak is smaller under controlled rectification; for the second peak, due to the no-load back EMF |E 02 |E is significantly smaller than that under uncontrolled rectification 01 |, so the second peak under controllable adjustment is also smaller.

[0118] In sudden loading situations, heavy loads require a large excitation current. On the one hand, the armature winding inductance limits the current rise time, causing the first voltage dip. On the other hand, the main motor's excitation current takes time to rise, causing the second voltage dip. With controlled rectification, when the output voltage is detected to be below a certain value, the controlled rectification control is activated to boost the voltage. Because the boost voltage regulation control has a fast response time of 1 / 6 of the electrical frequency cycle, it compensates for both voltage dips.

[0119] By adopting MOS tube boost and voltage regulation control, the dynamic characteristics of the three-stage starter-generator system can be improved, and the maximum voltage during load rejection can be effectively suppressed. The design method for a three-stage starter-generator power supply system for aviation low-voltage DC power supply proposed in this invention is suitable for manned aircraft with high reliability requirements. Compared with DC brushless starter-generator power supply systems, the three-stage starter-generator power supply system has higher reliability and easier maintenance. Compared with permanent magnet starter-generator power supply systems, the three-stage starter-generator power supply system can be demagnetized in the event of a fault, providing greater safety.

Claims

1. A design method for a three-stage generator power supply system for aviation low-voltage DC. The three-stage generator power supply system includes a three-stage starter generator and a starter generator controller. The three-stage starter generator includes a permanent magnet auxiliary exciter, a main exciter, a rotating rectifier tube, a main motor and a resolver; the starter generator controller includes a MOS tube three-phase full bridge, an AC excitation power supply, a voltage regulator, an auxiliary power supply, a control circuit, a current sensor S F With current sensor S dc The stator armature winding W of the permanent magnet auxiliary exciter PMG Output three-phase AC v PMG The A, B and C terminals are connected to the auxiliary power supply and the A, B and C input terminals of the voltage regulator respectively. The rotor armature winding W of the main exciter EM Output three-phase AC v EM Through the rotating rectifier and the main motor rotor excitation winding W ME Connection, stator excitation winding W of the main exciter EE The F+ and F- terminals are connected to the AC excitation power supply output terminal and the voltage regulator output terminal, and the stator armature winding W of the main motor MM Three-phase ACv M The A, B and C terminals of the MOSFET are connected to the A, B and C terminals of the MOSFET three-phase full bridge respectively. The rotating stator output speed position signal P is connected to the control circuit. The DC bus V dc The + and - ends of the MOSFET are connected to the DC bus V Adc + and - terminals, AC excitation power input V Bi The + and - ends of the output power input and the control circuit are connected, and the - end of the voltage regulator is connected to the DC bus V dc The - end of the MOS tube is connected to the three-phase AC current signal i ABC Connected to the control circuit, the control circuit outputs the driving signal G A Connected to the MOS tube three-phase full bridge, the control circuit outputs the drive signal G B and the switch control signal S B Connected to the AC excitation power supply, the control circuit outputs the drive signal G C and the switch control signal S C Connected to the voltage regulator, the two power outputs of the auxiliary power supply are V c1 、V c2 Connected to the control circuit, the auxiliary power supply outputs the current signal I D Connected to the control circuit, the power enable signal E output by the control circuit n Connect to the auxiliary power supply, current sensor S dc The power terminal, output signal I dc Respectively with the DC bus V dc + terminal, control circuit connection, current sensor S F The power end, output signal i F Respectively with the excitation winding W EE F+ terminal and control circuit connection; The MOS tube three-phase full bridge includes an A-phase bridge arm, a B-phase bridge arm, a C-phase bridge arm, and a filter capacitor C Adc , current sensor S A1 、S A2 and S A3 , driving signal G A Including G A1 , G A2 , G A3 , G A4 , G A5 With G A6 , three-phase AC current i ABC Including i A 、i B and i C The A end of the MOS tube three-phase full bridge and the A phase bridge arm upper tube Q A1 The source and lower tube Q A2 The drain connection of the A phase bridge arm upper tube Q A1 The drain and DC bus V Adc The + end of the bridge arm of phase A is connected to the lower tube Q A2 The source S and the DC bus V Adc The - end of the MOS tube three-phase full bridge is connected to the B end of the B phase bridge arm upper tube Q A3 The source S and the lower tube Q A4 The drain D is connected to the B phase bridge arm upper tube Q A3 The drain and DC bus V Adc The + end of the bridge arm of phase B is connected to the lower tube Q A4 The source and DC bus V Adc The - end of the MOS tube three-phase full bridge is connected to the C end of the C phase bridge arm upper tube Q A5 The source and lower tube Q A6 The drain connection of the C phase bridge arm upper tube Q A5 The drain and DC bus V Adc The + end of the C-phase bridge arm is connected to the lower tube Q A6 The source and DC bus V Adc - end connection, filter capacitor C Adc The two ends are connected to the DC bus V Adc The + and - terminals of the current sensor S A1 、S A2 and S A3 The power end is connected to the A, B and C terminals respectively, and the current sensor S A1 、S A2 and S A3 Respectively with the output signal i A 、i B and i C Corresponding connection, the driving signal G A1 , G A2 , G A3 , G A4 , G A5 and G A6 Respectively with Q A1 , Q A2 , Q A3 , Q A4 , Q A5 and Q A6 corresponding gate connections; The AC excitation power supply includes a diode D B1 , multiple boost DC / DC modules, filter capacitor C B , power tube Q B1 , Q B2 , Q B3 and Q B4 , relay SCR, drive signal G B Including G B1 , G B2 , G B3 and G B4 ; is input by V Bi The + terminal of the diode D B1 The anode of the diode D B1 The cathodes are connected to the + terminals of multiple step-up DC / DC modules, and the input V Bi The - end of the boost DC / DC module is connected to the - end of the input of the boost DC / DC module, and the + and - ends of the output of the boost DC / DC module are connected to the DC bus V s Connect the + and - terminals of the Bi - end and DC bus V s - end connection, filter capacitor C B The two ends are respectively DC bus V s The + and - ends are connected, Q B1 The drain and DC bus V s The + end of the relay SCR is connected; the relay SCR has two switches, the input end of the first switch is connected to the Q B1 The source and Q B2 The drain connection, Q B2 The source and DC bus V s - end connection, Q B3 The drain and DC bus V s The + end of the relay SCR is connected to the input of the second switch Q B3 The source S and Q B4 The drain connection, Q B4 The source and DC bus V s - end is connected, the output end of the switch in the relay SCR is connected to the output v Bo Connection, drive signal G B1 , G B2 , G B3 and G B4 Respectively with Q B1 , Q B2 , Q B3 and Q B4 The gate connection, switch control signal S B Connect to the control terminal of relay SCR; The voltage regulator includes a diode D C1 、D C2 、D C3 、D C4 、D C5 、D C6 and D C7 , power tube Q C1 , Q C2 and Q C3 , filter capacitor C C , relay GCR, drive signal G C Including G C1 ~G C3 ;A terminal and D terminal of the voltage regulator C1 Anode and D C2 The cathode of the regulator is connected to the B terminal of the D C3 Anode and D C4 The cathode of the regulator is connected to the C terminal of the D C5 Anode and D C6 Cathode connection; D C1 、D C3 and D C5 The cathode and DC bus V G The + end connection, D C2 、D C4 and D C6 The anode and DC bus V G - end connection, filter capacitor C C The two ends are respectively DC bus V G The + and - ends are connected, Q C1 The drain and DC bus V G The + end of the relay GCR is connected to the input of the first switch and Q C1 The source and Q C2 The drain connection, Q C2 The source and DC bus V G - end connection, D C7 The cathode and DC bus V G The + end of the relay GCR is connected to the input end of the second switch of D C7 Anode and Q C3 The drain connection, Q C3 The source and DC bus V G - end of the relay GCR is connected to the output V co The + and - terminals are connected, and the driving signal G C1 , G C2 and G C3 Respectively with Q C1 , Q C2 and Q C3 The gate connection, switch control signal S C Connect to the control terminal of relay SCR; The auxiliary power supply includes a diode D D1 、D D2 、D D3 and D D4 , non-isolated DC / DC module, first isolated DC / DC module, second isolated DC / DC module, current sensor S D ; The + terminal of the auxiliary power supply and D D1 Anode connection, D D1 The cathode is connected to the + terminal of the non-isolated DC / DC module output, D D2 、D D3 and D D4 The anode is connected to terminals A, B and C respectively, and D D2 、D D3 and D D4 The cathode is connected to the + end of the non-isolated DC / DC module input, the - end of the auxiliary power supply is connected to the - end of the non-isolated DC / DC module input, the - end of the non-isolated DC / DC module output, the - end of the first isolated DC / DC module output, and the - end of the second isolated DC / DC module output, and the + end and - end of the non-isolated DC / DC module output are respectively connected to the + end and - end of the first isolated DC / DC module input, and the + end and - end of the second isolated DC / DC module input; and also includes two power supplies, the + end and - end of the first isolated DC / DC module output are connected to the first power supply V c1 The + and - ends of the second isolated DC / DC module are connected to the + and - ends of the second power supply V c2 The + and - terminals of the current sensor S D The power terminal and the second power supply V c2 The + terminal of the current sensor S D Output signal I D , power enable signal E n Connected to the enable terminal E of the second isolated DC / DC module input; It is characterized by The following steps are involved: Step 1: Let the rated current be I N , ensuring that the three-stage starter generator can output 1.5I under the conditions of minimum generating speed and voltage regulation N ; Step 2: Ensure that the output voltage of the three-stage starter generator does not exceed 45V when the load current is switched from 150% to 20% at the highest generating speed; Step 3: Assume the average inductance of the main motor armature winding L = (L d +L q ) / 2, inductive reactance X at the highest generating speed max =ω max L, make 1.5I N X max <35V; Step 4: Assume the inductive reactance of the main exciter armature winding at the lowest generating speed is X emin , the resistance of the main motor excitation winding at the highest operating temperature is R emax , guarantee X emin / R emax >0.5; Step 5: Let the inductance of the main motor excitation winding be L e , the resistance at the lowest operating temperature is R emin , ensuring the time constant L e / R emin <50ms; Step 6: Under the condition of the generator speed range and the voltage regulator load from no load to maximum load, ensure that the rectified output voltage V of the permanent magnet auxiliary excitation in the three-stage starter generator is G In the range of 12V~45V; Step 7: Assume that the frequency of the AC excitation power supply is f, and the maximum effective value of the AC excitation current of the main exciter during startup is I Fmax , the excitation inductance of the main exciter is L ee , so that 130V < 2πfL ee I Fmax <170V; Step 8: The resolver stator outputs a speed position signal P including a speed signal n and a position signal θ. The position signal θ=0° corresponds to the zero-crossing point of the voltage drop section of the main motor phase A under no-load conditions. Step 9: For the DC bus V in the voltage regulator G The capacitor C C， Ensure that all energy in the main excitation winding is fed back to the capacitor C C When the capacitor C C The voltage on the MOSFET is still within the allowable range; Step 10: Use the auxiliary power supply to power the control circuit. The power supply V c2 Used to power the power tube drive circuit in the control circuit. The power supply V c1 Used to power other circuits in the control circuit. If the power supply V c2 The output current I D When abnormal, the power enable signal E n The isolated DC / DC module 2 in the isolated power supply is prohibited from operating; Step 11: During the starting process, the starter generator controller drives the three-stage starter generator from rest to the engine ignition speed; Step 12: After the engine reaches the power generation speed, it enters the power generation process. When the power generation speed and load change, the voltage regulator and MOS tube three-phase full bridge control stabilize the output DC voltage V dc .

2. The design method of the aviation low-voltage DC three-stage generator power supply system according to claim 1, characterized in that: The step 11 starting process includes the following steps: Step 1101: Output a switch control signal S via a control circuit B and S C , turn on the relay SCR switch and turn off the relay GCR switch; Step 1102: The 28V input voltage V is increased by the step-up DC / DC modules 1, 2, ... n in the AC excitation power supply. Bi Converted to 270V voltage V s , by connecting multiple boost DC / DC modules in parallel to increase output power; Step 1103: Q in the AC excitation power supply B1 ~Q B4 The single-phase H-bridge provided by the circuit provides AC excitation current to the main exciter; Step 1104: The control circuit adopts a quasi-speed outer loop and current inner loop control strategy, and generates a driving signal G for the MOS tube three-phase full bridge through sinusoidal space vector pulse width modulation (SVPWM) control. A , so that the starting process works in the maximum torque current ratio mode.

3. The design method of the aviation low-voltage DC three-stage generator power supply system according to claim 1, characterized in that: The power generation process in step 12 includes the following steps: Step 1201: Output a switch control signal S via a control circuit B and S C , disconnect the relay SCR switch and connect the relay GCR switch; Step 1202: The voltage regulator outputs the excitation current to adjust the output three-phase AC voltage of the main motor, thereby achieving the DC voltage V dc Voltage stabilization control; Step 1203: Use the MOS tube three-phase full bridge to realize the main motor output three-phase AC voltage v M To DC voltage V dc The synchronous rectification, on the other hand, realizes the voltage V dc Boost control when voltage is too low.

4. The design method of the aviation low-voltage DC three-stage generator power supply system according to claim 3, characterized in that: The voltage stabilization control described in step 1202 includes the following steps: Step 12021: Generate a drive signal G for the voltage regulator in the control circuit C1 , by adopting dual-loop control to generate power tube Q C1 The driving signal G C1 In the dual-loop control, the voltage loop is the outer loop, the excitation current loop is the inner loop, and the voltage outer loop is used to make the output voltage V dc Tracking parameter voltage V ref , and generates the current inner loop reference signal I fref The inner current loop is used to make the main exciter excitation current i F Tracking reference signal I fref The current inner loop output is used to control the power tube Q C1 Drive signal G C1 Duty cycle D; Step 12022: According to the output DC current I dc , determine the voltage outer loop reference voltage V ref , assuming the rated current is I N , in I dc <2I N When V ref =28V, at I dc By 2I N to 3I N When the V ref Reduce from 28V to 0V; Step 12023: Determine the maximum excitation current I allowed by the voltage loop output based on the input speed n fmax , I fmax For speed n, 1.5I N Under the condition of dc is the excitation current corresponding to the desired regulated voltage value; Step 12024: At the input voltage V dc <40V, the driving signal G C3 =1, power tube Q C3 Constant conduction, power tube Q C2 The driving signal G C2 With power tube Q C1 The driving signal G C1 Complementary conduction allows the freewheeling current to flow through the power tube Q C2 , not Q C2 The reverse parallel diode; Step 12025: At the input voltage V dc >40V, the driving signal G C1 ~G C3 are all equal to 0, the power tube Q C1 ~Q C3 Constant off, the excitation current of the main exciter passes through the power tube Q C2 The anti-parallel diode and diode D C7 , feeding energy back to the DC bus V G To achieve rapid demagnetization.

5. The design method of the aviation low-voltage DC three-stage generator power supply system according to claim 3, characterized in that: The boost control in step 1203 includes the following steps: Step 12031: According to the three-phase current i A 、i B and i C , determine the driving signal G of synchronous rectification control A1G ~G A6G , define the three-phase current i A 、i B and i C The direction of outflow from the starter generator controller is positive, I refH and I refL They are +1 / 5 and -1 / 5 of the rated current respectively. When i A >I refH When G A2G =1, otherwise G A2G =0, when i B >I refH When G A4G =1, otherwise G A4G =0, when i C >I refH When G A6G =1, otherwise G A6G =0, when i A refL When G A1G =1, otherwise G A1G =0, when i B refL When G A3G =1, otherwise G A3G =0, when i C refL When G A5G =1, otherwise G A5G =0;​​​ Step 12032: According to the DC voltage V dc , DC current I dc , determine the driving signal G for boost voltage regulation control A1O ~G A6O , define the driving signal G A2O The falling edge lag θ=180° is δ1, and the driving signal G A2O The high level pulse width is δ2, when the DC voltage V dc <24V and I dc <2I N When the active current i is increased by increasing the width of δ2 q Make the DC voltage stable at 24V, and adjust δ1 to make the reactive current i d =0, reducing δ1 corresponds to reducing the demagnetization reactive current i d , the adjustment range of δ1 is 0~60°, the adjustment range of δ2 is 0~90°, G A1O ~G A6O With the same positive pulse width, press G A2O , G A5O , G A4O , G A1O , G A6O , G A3O The boost voltage control drive signal G is formed in a 60° phase difference. A1O ~G A6O ; Step 12033: According to the driving signal G controlled by synchronous rectification A1G ~G A6G And the boost voltage control drive signal G A1O ~G A6O , determine the MOS tube three-phase full-bridge drive signal G A ,

Images