A starting controller and control method for a three-stage electrically excited synchronous motor for cryogenic starting of aircraft engines.

Abstract

This invention discloses a starting controller and control method for a three-stage electrically excited synchronous motor (EMM) designed for cryogenic starting of aero-engines. The indirect current control branch collects the armature current of the three-phase stator windings of the main generator of the three-stage EMM. By comparing the calculated effective value of the main generator's armature current with the current limit threshold within the current speed segment, it outputs an acceleration control coefficient to determine the control quantity for increasing or decreasing acceleration in the next speed control cycle of the speed closed-loop control loop. The acceleration segment control branch collects position signals from the internal position sensors of the three-stage EMM and outputs the corresponding acceleration control quantity to the speed closed-loop control loop based on the speed segment range in which the motor rotor speed is located. The acceleration control quantity and acceleration control coefficient are combined and used as the input quantity for the speed control deviation of the speed closed-loop control loop to prevent abrupt changes in the output of the speed closed-loop control loop.

Description

Technical Field

[0001] This invention relates to, but is not limited to, the field of aero-engine starting control technology, and particularly to a starting controller and control method for a three-stage electrically excited synchronous motor matched for low-temperature starting of aero-engines. Background Technology

[0002] The process of bringing an aircraft engine from a standstill (zero speed) to a speed at which it can operate independently is called engine starting. Currently, aircraft engine starting methods can be broadly categorized into air / gas turbine starter starting and electric starting. High-power aircraft engines use air / gas turbine starters, while medium- and low-power aircraft engines use direct current (DC) electric starters. With the development of aviation power supplies and power electronics technology, even high-power aircraft engines are beginning to adopt electric starting methods.

[0003] Currently, the electric starting method for high-power aero engines is based on direct torque angle closed-loop control. With this electric starting method, when the engine starts in a low-temperature environment, the starting load demand of the engine increases significantly. However, the speed closed-loop adjustment of the starting controller is not good, meaning that the engine speed rises relatively slowly during the engine starting process in a low-temperature environment. This results in a larger speed deviation between the actual speed and the target speed, leading to unsuccessful or difficult engine starting in a low-temperature environment. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned technical problems. This invention provides a starting controller and control method for a three-stage electrically excited synchronous motor that is matched for low-temperature starting of aero engines, so as to solve the problem that the existing electric starting method of high-power aero engines fails to start or has difficulty starting in low-temperature environments.

[0005] The technical solution of the present invention: The present invention provides a starting controller for a three-stage electrically excited synchronous motor that is matched for low-temperature starting of an aero-engine, comprising: an indirect current control branch, an acceleration segmented control branch, and a speed closed-loop control circuit;

[0006] The input terminal of the indirect current control branch is connected between the three-phase full-bridge inverter and the three-stage electrically excited synchronous motor, the input terminal of the acceleration segment control branch is connected to the three-stage electrically excited synchronous motor, the motor rotor speed calculated in the acceleration segment control branch is transmitted to the current limiting control module of the indirect current control branch, and the output terminals of the indirect current control branch and the acceleration segment control branch are connected in parallel to the speed closed-loop control loop.

[0007] The indirect current control branch is used to collect the armature current of the three-phase stator winding of the main generator of the three-stage electrically excited synchronous motor, calculate the effective value of the armature current of the main generator, and compare the effective value of the armature current of the main generator with the current limit threshold of the current speed segment in the current speed control loop within the current speed control cycle, and output the acceleration control coefficient, thereby determining the control amount of increasing speed or decreasing acceleration in the next speed control cycle of the speed closed loop control loop.

[0008] The acceleration segmented control branch is used to calculate the relative position and speed of the motor rotor by collecting the position signal from the internal position sensor of the three-stage electrically excited synchronous motor, and then output the acceleration control quantity corresponding to the speed segment to the speed closed-loop control loop based on the speed segment range in which the motor rotor speed is located.

[0009] The acceleration control quantity output by the acceleration segment control branch and the acceleration control coefficient output by the indirect current control branch are combined and used as the input quantity for the speed control deviation of the speed closed-loop control loop. This keeps the acceleration control quantity relatively fixed under the same motor rotor speed range, thereby preventing sudden changes in the output of the speed closed-loop control loop.

[0010] Optionally, in the starting controller of the three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine as described above, the indirect current control branch includes: a current acquisition module, a current effective value calculation module, a vector transformation module and a current limit control module connected in sequence, and the motor rotor speed calculated in the acceleration segment control branch is input to the speed input terminal of the current limit control module, and the motor rotor position is input to the vector transformation module.

[0011] The current acquisition module is connected between the three-phase full-bridge inverter and the three-stage electrically excited synchronous motor, and is used to acquire and calculate the three-phase stator winding armature current of the main generator of the three-stage synchronous motor; after being transformed by the vector inverse transformation module, the d-axis current i is output. d and q-axis current i q The effective value of the armature current of the main generator is calculated and output by the current effective value calculation module, and then transmitted to the current input terminal of the current limiting control module.

[0012] The current limiting control module is pre-configured with current limiting thresholds corresponding to various speed ranges. Based on the effective value of the armature current of the main generator in the current speed control cycle, it determines whether the next speed control cycle is to increase speed control or decrease acceleration control according to the current limiting thresholds corresponding to each speed range, and outputs the result to the speed closed-loop control loop.

[0013] Optionally, in the starting controller of the three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine as described above, the acceleration segment control branch includes: a position calculation module and the acceleration segment control branch connected to each other;

[0014] The position calculation module has its input terminal connected to a three-stage electrically excited synchronous motor, used to collect position signals from the internal position sensor of the three-stage electrically excited synchronous motor and calculate the relative position and speed of the motor rotor; the output terminal of the position calculation module is connected to the input terminal of the multi-segment acceleration control module, the position input terminal of the current limiting control module, and the input terminal of the vector transformation module, respectively.

[0015] The multi-segment acceleration control module is used to calculate the motor rotor speed based on the position calculation module, and output the acceleration control quantity corresponding to the speed segment to the speed closed-loop control loop according to the speed segment range in which the motor rotor speed is located.

[0016] Optionally, in the starting controller of the three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine as described above, the speed closed-loop control loop includes: a speed closed-loop control module;

[0017] The input terminal of the speed closed-loop control module is connected to the output terminals of the acceleration segmented control branch and the indirect current control branch, respectively. The speed control deviation after combining the acceleration control quantity and the acceleration control coefficient is used as the input, and the magnitude of the output voltage vector after speed closed-loop control is used to realize the closed-loop control of the speed of the three-stage electrically excited synchronous motor.

[0018] Optionally, in the starting controller of the three-stage electrically excited synchronous motor for low-temperature starting of aero-engines as described above, the speed closed-loop control loop further includes: a soft-start current closed-loop control module and a time-sharing control module.

[0019] The input terminal of the soft-start current closed-loop control module is connected to the output terminal of the current effective value calculation module, and the output terminals of the soft-start current closed-loop control module, the speed closed-loop control module, and the position calculation module are connected to the input terminal of the time-sharing control module.

[0020] The soft-start current closed-loop control module is pre-configured with a soft-start current closed-loop current limiting threshold, which is used to compare the effective value of the armature current of the main generator calculated by the current effective value calculation module with the soft-start current closed-loop current limiting threshold, and after adjusting the output voltage vector magnitude, output to the time-sharing control module to realize the current closed-loop current limiting control of the main generator.

[0021] The time-sharing control module is used to perform time-sharing control by the soft-start current closed-loop control module and the speed closed-loop control module based on the motor rotor speed transmitted by the position calculation module. The control method is as follows: when the motor rotor speed is before the soft-start switching speed, the magnitude of the voltage vector is determined by the soft-start current closed-loop control module; otherwise, the magnitude of the voltage vector is determined by the speed closed-loop control module.

[0022] Optionally, in the starting controller of the three-stage electrically excited synchronous motor for low-temperature starting of aero engines as described above, the speed closed-loop control loop further includes: a voltage vector control output module, a vector inverse conversion module, an SVPWM module, and a three-phase full-bridge inverter connected in sequence.

[0023] The input terminal of the voltage vector control output module is connected to the output terminal of the time-sharing control module, and the relative angle information between the voltage vector and the main generator rotor is input to the voltage vector control output module; the voltage vector control output module is used to perform control output according to the input voltage vector amplitude and the relative angle information between the voltage vector and the main generator rotor, and output the d-axis voltage control quantity and the q-axis voltage control quantity to the vector inverse transformation module.

[0024] The input of the vector inverse transformation module is also connected to the output of the position calculation module. It is used to obtain the α-axis voltage control quantity and β-axis voltage control quantity by inverse coordinate transformation based on the input d-axis voltage control quantity and q-axis voltage control quantity and the motor rotor position. The output is then sent to the SVPWM module. The SVPWM module controls the output of the control signals of each switching power transistor of the three-phase inverter.

[0025] Optionally, in the starting controller of the three-stage electrically excited synchronous motor for low-temperature starting of aero-engines as described above, the speed closed-loop control loop further includes: a current torque angle calculation module and a direct torque angle closed-loop control module connected to each other.

[0026] The input terminal of the current-torque angle calculation module is connected to the output terminal of the vector transformation module, and is used to calculate the d-axis current i obtained by the vector transformation module. d and q-axis current i q The tangent angles of the q-axis current and d-axis current are calculated, which are the current-torque angles of the main generator, and then output to the direct torque angle closed-loop control module.

[0027] The output of the direct torque angle closed-loop control module is connected to the voltage vector control output module. It is used to compare the input current torque angle of the main generator with the direct torque angle closed-loop target torque angle set in this control module. After adjusting the relative angle information between the output voltage vector and the main generator rotor, it is output to the voltage vector control output module to realize the closed-loop regulation of the current direct torque angle of the main generator and realize the control of the d-axis current of the main generator.

[0028] Optionally, in the starting controller of the three-stage electrically excited synchronous motor for low-temperature starting of an aircraft engine as described above,

[0029] The input terminal of the three-phase full-bridge inverter is the DC bus voltage and the isolated drive signal of each switch of the three-phase inverter. The output terminal is connected to the three-phase stator winding of the main generator of the three-stage electrically excited synchronous motor. After the rotor of the main generator is excited, the main generator is controlled to realize the motor's electric operation.

[0030] Secondly, embodiments of the present invention also provide a control method for a starter controller of a three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine, wherein the starter controller of the three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine, as described in any of the above embodiments, is used to perform start control on the three-stage electrically excited synchronous motor, the control method comprising:

[0031] The armature current of the three-phase stator winding of the main generator of the three-stage electrically excited synchronous motor is collected by the indirect current control branch. The effective value of the armature current of the main generator is calculated. In the current speed control cycle, the effective value of the armature current of the main generator is compared with the current limit threshold of the current speed segment. The acceleration control coefficient is output, thereby determining the control amount of increasing speed or decreasing acceleration in the next speed control cycle of the speed closed loop control loop.

[0032] The position signal of the internal position sensor of the three-stage electrically excited synchronous motor is collected by the acceleration segment control branch, and the relative position and speed of the motor rotor are calculated. Based on the speed range of the motor rotor, the acceleration control quantity corresponding to that speed range is output to the speed closed-loop control loop.

[0033] The acceleration control quantity output from the acceleration segment control branch and the acceleration control coefficient output from the indirect current control branch are combined and used as the input quantity for the speed control deviation of the speed closed-loop control loop. This keeps the acceleration control quantity relatively fixed under the same motor rotor speed range, thereby preventing sudden changes in the output of the speed closed-loop control loop.

[0034] Optionally, the control method for the starting controller of the three-stage electrically excited synchronous motor for low-temperature starting of an aircraft engine, as described above, specifically includes the following steps:

[0035] Step 1: Start the controller to obtain the actual value of the main generator armature current and the motor rotor position and speed through current acquisition and calculation;

[0036] Step 2: Perform vector transformation on the armature current of the three-phase main generator to obtain the d-axis current and q-axis current;

[0037] Step 3: Calculate the effective value of the armature current of the main generator using the effective value of the main generator armature current;

[0038] Step 4: Calculate the real-time torque angle of the main generator current using the armature current torque angle of the main generator;

[0039] Step 5: By comparing the current rotor speed with the soft start current closed-loop switching speed, if the current rotor speed is less than or equal to the soft start current loop switching speed, the output voltage vector amplitude is controlled by the soft start current closed-loop and the process proceeds directly to step 9; otherwise, the process proceeds to step 6.

[0040] Step 6: When the current rotor speed is greater than or equal to the soft start current loop switching speed, the current limit control threshold for this speed segment is obtained through the current limit control module. The effective value of the current armature current of the current main generator is compared with the current limit threshold for this speed segment. If the effective value of the current armature current of the current main generator is greater than the current limit threshold, it is set to deceleration control flag; otherwise, it is set to speed increase control flag.

[0041] Step 7: By determining the current rotor speed range, obtain the acceleration control quantity corresponding to that speed range through the multi-segment acceleration control module;

[0042] Step 8: Based on the acceleration control flag determined by the integrated current limiting control module and the acceleration control quantity determined by the multi-segment acceleration control module, the voltage vector amplitude is output through the adjustment of the speed closed-loop control module.

[0043] Step 9: Adjust the output voltage vector angle through the direct torque angle closed-loop control module, which is the relative angle information between the voltage vector and the main generator rotor;

[0044] Step 10: By synthesizing the voltage vector magnitude and voltage vector angle, the output is decomposed to obtain the d-axis voltage control quantity and the q-axis voltage control quantity;

[0045] Step 11: Obtain the α-axis voltage control quantity and β-axis voltage control quantity by performing inverse vector transformation on the d-axis voltage control quantity and the q-axis voltage control quantity;

[0046] Step 12: The α-axis voltage control quantity and β-axis voltage control quantity are output as control signals for the power switching transistors of the three-phase inverter through SVPWM control.

[0047] The beneficial effects of this invention are as follows: Addressing the problem of unsuccessful low-temperature starting of starter controllers during field tests of aero-engines, this invention provides a starter controller and control method for a three-stage electrically excited synchronous motor matched for low-temperature starting of aero-engines. This is essentially an improved control strategy based on indirect current limiting using a speed closed-loop system. This improved control strategy mainly includes the following three control schemes:

[0048] 1) Indirect Current Limitation Control Scheme: This control scheme designs current limit thresholds for different speed ranges based on the starting torque requirements of the engine at different speed ranges. The starting controller collects the three-phase stator winding armature current of the electrically excited synchronous motor's main generator, calculates the effective value of the main generator's armature current through transformation and decoupling, and compares the effective value of the main generator's armature current with the current limit threshold within the current speed range during the current control cycle of the speed closed-loop control. The output is the acceleration control coefficient, thereby determining the control quantity for increasing or decreasing acceleration in the next control cycle of the speed closed-loop control loop. The voltage vector amplitude is adjusted through speed closed-loop PI regulation to achieve indirect control of the main generator's armature current.

[0049] 2) Optimized control scheme for given speed closed-loop control variables: The actual motor speed is obtained by judging and collecting data. The acceleration control quantity for that speed segment is directly obtained through a multi-segment acceleration control module. This acceleration control quantity, along with the acceleration control coefficient output by the comprehensive current limiting control, is directly used as the speed control deviation input for the speed closed-loop control loop. Figure 5 The diagram shown is a schematic of the optimized speed closed-loop control. This control scheme can relatively fix the acceleration control quantity under the same motor rotor speed range. This can effectively control the output of the speed closed-loop control loop and prevent sudden changes, thereby making the speed increase of the starter controller relatively smooth and improving the robustness of the starter controller.

[0050] 3) Optimized control scheme for speed closed-loop control output: The actual motor speed is obtained by judgment and acquisition. When the motor speed is less than the soft start current closed-loop switching speed, the voltage vector amplitude control output is realized by the soft start current closed-loop to realize the motor starting from standstill to low speed. When the speed is greater than the soft start current closed-loop switching speed, the voltage vector amplitude control is realized by the speed closed-loop, thereby reducing the large torque impact generated during static start-up.

[0051] The improved control strategy provided by the embodiments of the present invention can better match the low-temperature starting characteristics of the engine without increasing the hardware output capability of the starter controller, meet the low-temperature starting requirements of the engine, and effectively solve the problem of matching starter control between the three-stage electrically excited synchronous motor and the engine system in low-temperature environment. Attached Figure Description

[0052] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0053] Figure 1 This is a schematic diagram of the existing three-stage brushless synchronous motor starting system;

[0054] Figure 2 This is a schematic diagram illustrating the principle of the starting control method for an existing three-stage electrically excited synchronous motor for aviation based on direct torque angle closed-loop control.

[0055] Figure 3 This is a schematic diagram of the speed closed-loop control following curve for the existing three-stage electrically excited synchronous motor in aviation under low temperature conditions.

[0056] Figure 4 A schematic diagram of the circuit structure of a starting controller for a three-stage electrically excited synchronous motor that is matched for low-temperature starting of an aero-engine, provided in an embodiment of the present invention;

[0057] Figure 5 This is a schematic diagram of the speed closed-loop control following of the starting controller of the three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine, as provided in an embodiment of the present invention.

[0058] Figure 6 A hardware circuit block diagram of a starting controller for a three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine, provided in an embodiment of the present invention;

[0059] Figure 7 The present invention also provides a flowchart of a control method for a starting controller of a three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine;

[0060] Figure 8 This is a schematic diagram illustrating the principle of the segmented current limiting scheme under current limiting control in the starter controller provided in an embodiment of the present invention.

[0061] Figure 9 The waveforms of excitation current and main generator armature current during low-temperature starting are shown in the traditional starting control scheme.

[0062] Figure 10The waveforms of excitation current and main generator armature current during the low-temperature start-up process of the starter controller provided in this embodiment of the invention are shown. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

[0064] As explained in the background section, high-power aero engines have begun to adopt electric starting methods. The starting process of an aero engine is relatively complex. Previous research has enabled the implementation of a three-stage electrically excited synchronous motor high-power AC starting control method, such as... Figure 1 The diagram shows the structure of an existing three-stage brushless synchronous motor starting system. Structurally, the three-stage electrically excited synchronous motor consists of four parts: a permanent magnet motor, an exciter, a rotating rectifier, and a main generator. The permanent magnet motor rotor, exciter rotor, main generator rotor, and rotating rectifier are coaxially mounted. The permanent magnet motor does not participate in the motor starting process; the starting controller mainly consists of exciter control and main generator control drives. Based on preliminary engineering tests, a three-stage electrically excited synchronous motor starting control method is currently used, which can meet the basic starting requirements of high-power aero-engines. Figure 2 The diagram shows the principle of the starting control method for a three-stage electrically excited synchronous motor in aviation based on direct torque angle closed-loop control. This starting control method involves directly controlling the magnitude of the voltage vector through a speed closed-loop PI regulator and adjusting the relative position of the voltage vector with the main generator rotor through a current closed-loop PI regulator, thereby controlling the torque angle of the main generator. This directly determines the output voltage vector of the starting controller. Then, a switching signal for the three-phase full-bridge inverter is generated via space vector modulation (SVPWM) to control the three-phase full-bridge inverter to drive the main generator output, thus achieving the starting control of the three-stage electrically excited synchronous motor. The advantages of this starting control method are that it requires fewer control targets, effectively reduces electromagnetic disturbances from the exciter to the main generator, and optimizes the load-carrying capacity and speed regulation performance of traditional vector control under high-speed, heavy-load conditions.

[0065] In existing starting control strategies for electrically excited synchronous motors based on direct torque angle control, the speed closed-loop employs a multi-segment acceleration starting control method. Specifically, based on the engine's starting characteristics, the engine is segmented at different speeds, and the acceleration at each stage within that speed range is determined through calculation and experimentation. This is then used to adjust the voltage vector amplitude output at different speeds through speed closed-loop control, achieving speed closed-loop control during the motor's starting process. The shortcomings of this existing control strategy are: when the engine starts in low-temperature environments, the starting load demand increases significantly, but the speed closed-loop adjustment of the starting controller is not very responsive, resulting in a relatively slow speed increase during engine starting in low-temperature environments. This leads to a larger speed deviation between the actual speed and the target speed. Figure 3 The figure shows a schematic diagram of the speed closed-loop control following curve of the existing three-stage electrically excited synchronous motor starting control at low temperatures. It can be seen that as the deviation between the actual speed and the target speed of the speed closed-loop control gradually increases, the amplitude of the voltage vector output by the PI regulation will gradually increase, and through the main generator control drive output, the armature current output of the three-phase main generator will increase, which can easily trigger the overcurrent protection of the starting controller and terminate the start-up.

[0066] To address the aforementioned problems, this invention provides a starting controller and control method for a three-stage electrically excited synchronous motor that is compatible with the low-temperature starting of an aero-engine. By studying the matching design problem between the starting controller of the three-stage electrically excited synchronous motor and the starting of an aero-engine in a low-temperature environment, a starting control scheme for the electrically excited synchronous motor based on indirect current limiting of speed closed loop is proposed to solve the problem of unsuccessful or difficult starting of the engine in a low-temperature environment.

[0067] The present invention provides the following specific embodiments, which can be combined with each other. For the same or similar concepts or processes, they may not be described again in some embodiments.

[0068] Figure 4 This is a schematic diagram of the circuit structure of a starting controller for a three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine, provided as an embodiment of the present invention. Figure 4 As shown in the embodiment of the present invention, the main structure of the starting controller for a three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine includes: an indirect current control branch, an acceleration segmented control branch, and a speed closed-loop control circuit.

[0069] like Figure 4In the structure of the starting controller for the three-stage electrically excited synchronous motor shown, the input terminal of the indirect current control branch is connected between the three-phase full-bridge inverter and the three-stage electrically excited synchronous motor, the input terminal of the acceleration segment control branch is connected to the three-stage electrically excited synchronous motor, the motor rotor speed calculated in the acceleration segment control branch is transmitted to the current limiting control module of the indirect current control branch, and the output terminals of the indirect current control branch and the acceleration segment control branch are connected in parallel to the speed closed-loop control loop.

[0070] The indirect current control branch in this embodiment of the invention is used to collect the armature current of the three-phase stator winding of the main generator of the three-stage electrically excited synchronous motor, calculate the effective value of the armature current of the main generator, and compare the effective value of the armature current of the main generator with the current limit threshold of the current speed segment in the current speed control loop within the current speed control cycle, and output the acceleration control coefficient, thereby determining the control amount of increasing speed or decreasing acceleration in the next speed control cycle of the speed closed loop control loop.

[0071] The acceleration segmented control branch in this embodiment of the invention is used to calculate the relative position and speed of the motor rotor by collecting the position signal of the internal position sensor of the three-stage electrically excited synchronous motor, and then output the acceleration control quantity corresponding to the speed segment to the speed closed-loop control loop based on the speed segment range in which the motor rotor speed is located.

[0072] In this embodiment of the invention, the acceleration control quantity output by the acceleration segment control branch and the acceleration control coefficient output by the indirect current control branch are combined and used as the input quantity for the speed control deviation of the speed closed-loop control loop, so as to relatively fix the acceleration control quantity under the same motor rotor speed range, thereby preventing the output of the speed closed-loop control loop from changing abruptly.

[0073] Based on the analysis and research of existing starter controllers for electrically excited synchronous motors (EMS) based on direct torque angle control, this invention proposes a starter controller for a three-stage EMS that is compatible with the low-temperature starting of aero-engines. This is essentially an improved control scheme for an EMS based on indirect current limiting using a speed closed-loop control. The main approach involves designing current limiting thresholds and acceleration control quantities for different engine speed ranges based on the starting torque requirements of the engine at different speed ranges, building upon speed closed-loop control. The starter controller collects the armature current of the three-phase main generator and calculates the effective value of the main generator's armature current through transformation and decoupling. Within the current control cycle of the speed closed loop, the main generator's armature current is compared with the current limiting control threshold to directly determine whether the next control cycle of the speed closed loop will involve increasing speed or decreasing acceleration. This allows for indirect control of the main generator's armature current by adjusting the amplitude of the output control voltage vector. The control scheme provided by this invention can better match the low-temperature starting characteristics of the engine and meet the engine's low-temperature starting requirements without increasing the hardware output capability of the starter controller.

[0074] The following describes the various control schemes in the starting controller of the three-stage electrically excited synchronous motor provided in the embodiments of the present invention.

[0075] (1) Indirect current control branch:

[0076] like Figure 4 As shown, the indirect current control branch includes: a current acquisition module, a current effective value calculation module, a vector transformation module, and a current limit control module connected in sequence; in addition, the motor rotor speed calculated in the acceleration segmented control branch is input to the speed input terminal of the current limit control module, and the motor rotor position is input to the vector transformation module.

[0077] The current acquisition module is connected between the three-phase full-bridge inverter and the three-stage electrically excited synchronous motor. It is used to acquire and calculate the three-phase stator winding armature current of the main generator of the three-stage synchronous motor. After being transformed by the vector inverse conversion module, the d-axis current i is output. d and q-axis current i q The effective value of the armature current of the main generator is calculated and output by the current effective value calculation module, and then transmitted to the current input terminal of the current limiting control module.

[0078] The current limiting control module is pre-configured with current limiting thresholds for various speed ranges. Based on the effective value of the main generator's armature current within the current speed control cycle, it determines whether the next speed control cycle should be either speed increase control or acceleration decrease control, and outputs this information to the speed closed-loop control loop. For example... Figure 8The diagram shown is a schematic diagram of the segmented current limiting scheme under current limiting control in the starter controller provided in an embodiment of the present invention.

[0079] (2) Acceleration segmented control branch:

[0080] like Figure 4 As shown, the acceleration segmented control branch includes: a position calculation module and the acceleration segmented control branch connected together.

[0081] The position calculation module has its input end connected to a three-stage electrically excited synchronous motor to collect position signals from the internal position sensor of the three-stage electrically excited synchronous motor and calculate the relative position and speed of the motor rotor. The output end of the position calculation module is connected to the input end of the multi-segment acceleration control module, the position input end of the current limiting control module, and the input end of the vector transformation module.

[0082] The multi-segment acceleration control module is used to calculate the motor rotor speed based on the position calculation module, and output the acceleration control quantity corresponding to the speed segment to the speed closed-loop control loop according to the speed segment range in which the motor rotor speed is located.

[0083] (3) Speed ​​closed-loop control loop:

[0084] like Figure 4 As shown, the speed closed-loop control loop includes: a speed closed-loop control module, a time-sharing control module, a voltage vector control output module, a vector inverse conversion module, an SVPWM module, and a three-phase full-bridge inverter connected in sequence; in addition, it also includes: a soft-start current closed-loop control module, a current torque angle calculation module, and a direct torque angle closed-loop control module connected to it.

[0085] On the one hand, the speed closed-loop control form of the speed closed-loop control circuit is as follows: the input terminal of the speed closed-loop control module is connected to the output terminal of the acceleration segment control branch and the indirect current control branch respectively. The speed control deviation after the acceleration control quantity and acceleration control coefficient are combined is used as the input. The magnitude of the output voltage vector after speed closed-loop control is used to realize the closed-loop control of the speed of the three-stage electrically excited synchronous motor.

[0086] On the other hand, the speed closed-loop control loop also has a current closed-loop control form, specifically: the input terminal of the soft-start current closed-loop control module is connected to the output terminal of the current effective value calculation module, and the output terminals of the soft-start current closed-loop control module, the speed closed-loop control module, and the position calculation module are connected to the input terminal of the time-sharing control module.

[0087] The soft-start current closed-loop control module is pre-configured with a soft-start current closed-loop current limiting threshold. This threshold is used to compare the effective value of the main generator's armature current calculated by the current effective value calculation module with the soft-start current closed-loop current limiting threshold. The output voltage vector is then adjusted and output to the time-sharing control module to achieve current closed-loop current limiting control of the main generator.

[0088] Based on the aforementioned speed closed-loop control and current closed-loop current limiting control, output mode optimization control is achieved through a time-sharing control module. Specifically, the time-sharing control module performs time-sharing control based on the motor rotor speed transmitted by the position calculation module, using the soft-start current closed-loop control module and the speed closed-loop control module. The control method is as follows: when the motor rotor speed is before the soft-start speed switching, the voltage vector amplitude is determined by the soft-start current closed-loop control module; otherwise, the voltage vector amplitude is determined by the speed closed-loop control module.

[0089] The speed closed-loop control loop outputs the voltage vector amplitude through the time-sharing control module, and then, via the voltage vector control output module, vector inverse conversion module, and SVPWM module, outputs the control signals for each power switch of the three-phase inverter. The specific method is as follows:

[0090] The input terminal of the voltage vector control output module is connected to the output terminal of the time-sharing control module, and the relative angle information between the voltage vector and the main generator rotor is input to the voltage vector control output module. This voltage vector control output module is used to perform control output based on the input voltage vector amplitude and the relative angle information between the voltage vector and the main generator rotor, and output the d-axis voltage control quantity and the q-axis voltage control quantity to the vector inverse transformation module.

[0091] The input of the vector inverse transformation module is also connected to the output of the position calculation module. It is used to obtain the α-axis voltage control quantity and β-axis voltage control quantity by inverse coordinate transformation based on the input d-axis voltage control quantity and q-axis voltage control quantity and the motor rotor position. The output is then sent to the SVPWM module. The SVPWM module controls the output of the control signals for each power switch of the three-phase inverter.

[0092] It should be noted that the relative angle information between the voltage vector input to the voltage vector control output module and the main generator rotor is generated by the connected current torque angle calculation module and direct torque angle closed-loop control module. Specifically, the input terminal of the current torque angle calculation module is connected to the output terminal of the vector transformation module, used to calculate the d-axis current i obtained by the vector transformation module. d and q-axis current i q The tangent angles of the q-axis current and d-axis current are calculated, which are the current-torque angles of the main generator, and then output to the direct torque angle closed-loop control module.

[0093] In addition, the output of the direct torque angle closed-loop control module is connected to the voltage vector control output module. It is used to compare the input current torque angle of the main generator with the direct torque angle closed-loop target torque angle set in this control module. After adjusting the relative angle information between the output voltage vector and the main generator rotor, it is output to the voltage vector control output module to realize the direct torque angle closed-loop regulation of the main generator current and realize the control of the d-axis current of the main generator.

[0094] The input of the three-phase full-bridge inverter is the DC bus voltage and the isolated drive signals of each switch of the three-phase inverter. The output is connected to the three-phase stator winding of the main generator of the three-stage electrically excited synchronous motor. After the rotor of the main generator is excited, the main generator is controlled to realize the motor's electric operation.

[0095] like Figure 4 The diagram shown illustrates the following process of the speed closed-loop control of the three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine, using the starting controller provided in this embodiment of the invention. Compared to... Figure 3 The tracking effect between the actual speed and the target speed is significantly improved.

[0096] To address the issue of unsuccessful low-temperature starting of the starter controller during field testing of an aero-engine, this invention provides a three-stage electrically excited synchronous motor starter controller and its control method for low-temperature starting of an aero-engine. This is essentially an improved control strategy based on indirect current limiting using a speed closed-loop control. This improved control strategy mainly includes the following three control schemes:

[0097] 1) Indirect Current Limitation Control Scheme: This control scheme designs current limit thresholds for different speed ranges based on the starting torque requirements of the engine at different speed ranges. The starting controller collects the three-phase stator winding armature current of the electrically excited synchronous motor's main generator, calculates the effective value of the main generator's armature current through transformation and decoupling, and compares the effective value of the main generator's armature current with the current limit threshold within the current speed range during the current control cycle of the speed closed-loop control. The output is the acceleration control coefficient, thereby determining the control quantity for increasing or decreasing acceleration in the next control cycle of the speed closed-loop control loop. The voltage vector amplitude is adjusted through speed closed-loop PI regulation to achieve indirect control of the main generator's armature current.

[0098] 2) Optimized control scheme for given speed closed-loop control variables: The actual motor speed is obtained by judging and collecting data. The acceleration control quantity for that speed segment is directly obtained through a multi-segment acceleration control module. This acceleration control quantity, along with the acceleration control coefficient output by the comprehensive current limiting control, is directly used as the speed control deviation input for the speed closed-loop control loop. Figure 5 The diagram shown is a speed closed-loop control following schematic of a starter controller for a three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine, provided by an embodiment of the present invention. This control scheme can relatively fix the acceleration control quantity under the same motor rotor speed range, thus effectively controlling the output of the speed closed-loop control loop and preventing sudden changes. This results in a relatively smooth output increase in the speed of the starter controller, improving the robustness of the starter controller.

[0099] 3) Optimized control scheme for speed closed-loop control output: The actual motor speed is obtained by judgment and acquisition. When the motor speed is less than the soft start current closed-loop switching speed, the voltage vector amplitude control output is realized by the soft start current closed-loop to realize the motor starting from standstill to low speed. When the speed is greater than the soft start current closed-loop switching speed, the voltage vector amplitude control is realized by the speed closed-loop, thereby reducing the large torque impact generated during static start-up.

[0100] The improved control strategy provided by the embodiments of the present invention can better match the low-temperature starting characteristics of the engine without increasing the hardware output capability of the starter controller, meet the low-temperature starting requirements of the engine, and effectively solve the problem of matching starter control between the three-stage electrically excited synchronous motor and the engine system in low-temperature environment.

[0101] like Figure 6 The diagram shown is a hardware circuit block diagram of a starter controller for a three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine, provided in an embodiment of the present invention. The hardware circuit of this starter controller includes: a rectifier circuit, a soft-start circuit, a support filter circuit, a three-phase full-bridge inverter, a single-phase H-bridge inverter, a boost power supply, an integrated power supply, an input conditioning circuit, an output conditioning circuit, an isolation drive circuit, a position calculation circuit, a current acquisition circuit, a communication circuit, and a control circuit.

[0102] The rectifier circuit, soft-start circuit, and support filter circuit connected in sequence are used to internally rectify and filter the input three-phase AC power supply to output a stable DC bus voltage, which is then output to the input of the boost power supply and the power supply of the three-phase full-bridge inverter, respectively.

[0103] The input of the three-phase full-bridge inverter is the rectified and filtered DC bus voltage and the control signal of the isolated drive circuit. The output is connected to the three-phase stator winding of the main generator of the three-stage electrically excited synchronous motor. After the rotor of the main generator is excited, the main generator is controlled to realize the motor's electric operation.

[0104] The input of the single-phase H-bridge inverter is the high-voltage output of the boost power supply and the control signal of the isolated drive circuit. The output is connected to the stator single-phase winding of the three-stage electrically excited synchronous motor exciter to realize the rotor excitation control of the main generator in the starting state.

[0105] The integrated power supply receives an external control power supply as its input and outputs a multi-channel control power supply, used to power the internal modules of the starter controller.

[0106] The input terminal of the input conditioning circuit receives external input commands, which are then conditioned internally and input to the control circuit for identification of input commands and status.

[0107] The output conditioning circuit takes the control commands output by the control circuit and outputs them to external related devices via the drive isolation circuit, thereby realizing logic conversion control and status feedback.

[0108] The input terminal of the isolation drive circuit is the drive control signal output by the control circuit. After isolation and amplification, it is output to the single-phase H-bridge inverter and the three-phase full-bridge inverter to realize the excitation of the exciter and the power drive output of the stator winding of the main generator.

[0109] The position calculation circuit obtains the rotor position and speed by applying an excitation signal to the excitation winding of the rotary transformer inside the motor and receiving the position signal from the output winding of the rotary transformer.

[0110] The current acquisition circuit collects and conditions the three-phase stator armature current of the main generator during the startup process, and then inputs it to the control circuit for the calculation of the effective value of the main generator armature current and the current torque angle.

[0111] The communication circuit takes the communication information input from the control circuit, isolates it through the driver, and outputs it to the host computer to realize information interaction.

[0112] The control circuit realizes the integrated control unit of the starter controller, completes the acquisition and processing of input and output signals and control output, and implements the control strategy and control algorithm.

[0113] Based on the above embodiments of the present invention, a starting controller for a three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine is provided, such as... Figure 7 The diagram shows a flowchart of a control method for a starter controller of a three-stage electrically excited synchronous motor for cryogenic starting of an aircraft engine, as provided in an embodiment of the present invention. The starter controller of the three-stage electrically excited synchronous motor for cryogenic starting of an aircraft engine, provided in any of the above embodiments, is used to perform start control on the three-stage electrically excited synchronous motor. The control method includes:

[0114] Step 1: First, start the controller to obtain the actual value of the main generator armature current and the motor rotor position and speed through current acquisition and calculation;

[0115] Step 2: Perform vector transformation on the armature current of the three-phase main generator to obtain the d-axis current and q-axis current;

[0116] Step 3: Calculate the effective value of the armature current of the main generator using the effective value of the main generator armature current;

[0117] Step 4: Calculate the real-time torque angle of the main generator current using the armature current torque angle of the main generator;

[0118] Step 5: By comparing the current rotor speed with the soft start current closed-loop switching speed, if the current rotor speed is less than or equal to the soft start current loop switching speed, the output voltage vector amplitude is controlled by the soft start current closed-loop and the process proceeds directly to step 9; otherwise, the process proceeds to step 6.

[0119] Step 6: When the current rotor speed is greater than or equal to the soft start current loop switching speed, the current limit control threshold for this speed segment is obtained through the current limit control module. The effective value of the current armature current of the current main generator is compared with the current limit threshold for this speed segment. If the effective value of the current armature current of the current main generator is greater than the current limit threshold, it is set to deceleration control flag; otherwise, it is set to speed increase control flag.

[0120] Step 7: By determining the current rotor speed range, obtain the acceleration control quantity corresponding to that speed range through the multi-segment acceleration control module;

[0121] Step 8: Based on the acceleration control flag determined by the integrated current limiting control module and the acceleration control quantity determined by the multi-segment acceleration control module, the voltage vector amplitude is output through the adjustment of the speed closed-loop control module.

[0122] Step 9: Adjust the output voltage vector angle through the direct torque angle closed-loop control module, which is the relative angle information between the voltage vector and the main generator rotor;

[0123] Step 10: By synthesizing the voltage vector magnitude and voltage vector angle, the output is decomposed to obtain the d-axis voltage control quantity and the q-axis voltage control quantity;

[0124] Step 11: Obtain the α-axis voltage control quantity and β-axis voltage control quantity by performing inverse vector transformation on the d-axis voltage control quantity and the q-axis voltage control quantity;

[0125] Step 12: The α-axis voltage control quantity and β-axis voltage control quantity are output as control signals for the power switching transistors of the three-phase inverter through SVPWM control.

[0126] Figure 9 The waveforms of excitation current and main generator armature current during low-temperature starting are shown in the traditional starting control scheme. Figure 10 The waveforms of excitation current and main generator armature current during the low-temperature start-up process of the starter controller provided in this embodiment of the invention are shown.

[0127] This invention proposes an indirect current limiting control strategy based on a speed closed-loop control. This strategy requires comprehensive consideration of the starter controller's maximum hardware output capability, meeting the torque output requirements of the starting system, and setting appropriate current limiting control threshold parameters. This ensures that the starting system maintains a relatively large torque output before successful engine ignition, guaranteeing that the torque output of the starting system covers the entire engine starting speed range's torque curve throughout the entire starting process. The segmented current limiting design scheme under current limiting control is as follows: Figure 8 As shown, under the premise of ensuring the reliable output capability of the starter controller, the current limiting control threshold parameters and corresponding speed switching points can be adaptively adjusted according to the engine's starting needs in all environments, thus solving the engine's low-temperature starting matching design problem. The improved starter control strategy proposed in this invention has been verified through low-temperature ground starting in field flight tests, showing good improvement results. Specifically, the starter controller outputs the starting excitation current and main generator armature current in the low-temperature environment as the engine completes the starting excitation current and main generator armature current outputs, as shown in the diagram. Figure 9 and Figure 10 As shown, the improved starter controller can indirectly limit the main generator armature current output to near the current limit control threshold when starting the engine in a lower temperature environment.

[0128] In summary, the three-stage electrically excited synchronous motor starting control method for matching the low-temperature start of aero-engines proposed in this invention is actually an improved control strategy based on indirect current limiting of speed closed loop. It can fully meet the low-temperature start requirements of the engine and effectively solve the matching start control problem of the three-stage electrically excited synchronous motor with the engine system in low-temperature environment.

[0129] While the embodiments disclosed in this invention are as described above, they are merely illustrative of the embodiments to facilitate understanding of the invention and are not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A starting controller for a three-stage electrically excited synchronous motor for low-temperature starting of an aircraft engine, characterized in that, include: Indirect current control branch, acceleration segmented control branch, speed closed-loop control circuit; The input terminal of the indirect current control branch is connected between the three-phase full-bridge inverter and the three-stage electrically excited synchronous motor, the input terminal of the acceleration segment control branch is connected to the three-stage electrically excited synchronous motor, the motor rotor speed calculated in the acceleration segment control branch is transmitted to the current limiting control module of the indirect current control branch, and the output terminals of the indirect current control branch and the acceleration segment control branch are connected in parallel to the speed closed-loop control loop. The indirect current control branch is used to collect the armature current of the three-phase stator winding of the main generator of the three-stage electrically excited synchronous motor, calculate the effective value of the armature current of the main generator, and compare the effective value of the armature current of the main generator with the current limit threshold of the current speed segment in the current speed control loop within the current speed control cycle, and output the acceleration control coefficient, thereby determining the control amount of increasing speed or decreasing acceleration in the next speed control cycle of the speed closed loop control loop. The acceleration segmented control branch is used to calculate the relative position and speed of the motor rotor by collecting the position signal from the internal position sensor of the three-stage electrically excited synchronous motor, and then output the acceleration control quantity corresponding to the speed segment to the speed closed-loop control loop based on the speed segment range in which the motor rotor speed is located. The acceleration control quantity output by the acceleration segment control branch and the acceleration control coefficient output by the indirect current control branch are combined and used as the input quantity for the speed control deviation of the speed closed-loop control loop. This keeps the acceleration control quantity relatively fixed under the same motor rotor speed range, thereby preventing sudden changes in the output of the speed closed-loop control loop.

2. The starting controller for a three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine as described in claim 1, characterized in that, The indirect current control branch includes: a current acquisition module, a current effective value calculation module, a vector transformation module and a current limit control module connected in sequence, and the motor rotor speed calculated in the acceleration segmented control branch is input to the speed input terminal of the current limit control module, and the motor rotor position is input to the vector transformation module; The current acquisition module is connected between the three-phase full-bridge inverter and the three-stage electrically excited synchronous motor, and is used to acquire and calculate the three-phase stator winding armature current of the main generator of the three-stage synchronous motor; after being transformed by the vector inverse transformation module, the d-axis current i is output. d and q-axis current i q The effective value of the armature current of the main generator is calculated and output by the current effective value calculation module, and then transmitted to the current input terminal of the current limiting control module. The current limiting control module is pre-configured with current limiting thresholds corresponding to various speed ranges. Based on the effective value of the armature current of the main generator in the current speed control cycle, it determines whether the next speed control cycle is to increase speed control or decrease acceleration control according to the current limiting thresholds corresponding to each speed range, and outputs the result to the speed closed-loop control loop.

3. The starting controller for a three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine as described in claim 2, characterized in that, The acceleration segmented control branch includes: a position calculation module and the acceleration segmented control branch connected together; The position calculation module has its input terminal connected to a three-stage electrically excited synchronous motor, used to collect position signals from the internal position sensor of the three-stage electrically excited synchronous motor and calculate the relative position and speed of the motor rotor; the output terminal of the position calculation module is connected to the input terminal of the multi-segment acceleration control module, the position input terminal of the current limiting control module, and the input terminal of the vector transformation module, respectively. The multi-segment acceleration control module is used to calculate the motor rotor speed based on the position calculation module, and output the acceleration control quantity corresponding to the speed segment to the speed closed-loop control loop according to the speed segment range in which the motor rotor speed is located.

4. The starting controller for a three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine as described in claim 3, characterized in that, The speed closed-loop control loop includes: a speed closed-loop control module; The input terminal of the speed closed-loop control module is connected to the output terminals of the acceleration segmented control branch and the indirect current control branch, respectively. The speed control deviation after combining the acceleration control quantity and the acceleration control coefficient is used as the input, and the magnitude of the output voltage vector after speed closed-loop control is used to realize the closed-loop control of the speed of the three-stage electrically excited synchronous motor.

5. The starting controller for a three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine as described in claim 4, characterized in that, The speed closed-loop control loop also includes: a soft-start current closed-loop control module and a time-sharing control module; The input terminal of the soft-start current closed-loop control module is connected to the output terminal of the current effective value calculation module, and the output terminals of the soft-start current closed-loop control module, the speed closed-loop control module, and the position calculation module are connected to the input terminal of the time-sharing control module. The soft-start current closed-loop control module is pre-configured with a soft-start current closed-loop current limiting threshold, which is used to compare the effective value of the armature current of the main generator calculated by the current effective value calculation module with the soft-start current closed-loop current limiting threshold, and after adjusting the output voltage vector magnitude, output to the time-sharing control module to realize the current closed-loop current limiting control of the main generator. The time-sharing control module is used to perform time-sharing control by the soft-start current closed-loop control module and the speed closed-loop control module based on the motor rotor speed transmitted by the position calculation module. The control method is as follows: when the motor rotor speed is before the soft-start switching speed, the magnitude of the voltage vector is determined by the soft-start current closed-loop control module; otherwise, the magnitude of the voltage vector is determined by the speed closed-loop control module.

6. The starting controller for a three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine as described in claim 5, characterized in that, The speed closed-loop control circuit further includes: a voltage vector control output module, a vector inverse conversion module, an SVPWM module, and a three-phase full-bridge inverter connected in sequence; The input terminal of the voltage vector control output module is connected to the output terminal of the time-sharing control module, and the relative angle information between the voltage vector and the main generator rotor is input to the voltage vector control output module; the voltage vector control output module is used to perform control output according to the input voltage vector amplitude and the relative angle information between the voltage vector and the main generator rotor, and output the d-axis voltage control quantity and the q-axis voltage control quantity to the vector inverse transformation module. The input of the vector inverse transformation module is also connected to the output of the position calculation module. It is used to obtain the α-axis voltage control quantity and β-axis voltage control quantity by inverse coordinate transformation based on the input d-axis voltage control quantity and q-axis voltage control quantity and the motor rotor position. The output is then sent to the SVPWM module. The SVPWM module controls the output of the control signals of each switching power transistor of the three-phase inverter.

7. The starting controller for a three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine as described in claim 6, characterized in that, The speed closed-loop control loop further includes: a current torque angle calculation module and a direct torque angle closed-loop control module connected to each other; The input terminal of the current-torque angle calculation module is connected to the output terminal of the vector transformation module, and is used to calculate the d-axis current i obtained by the vector transformation module. d and q-axis current i q The tangent angles of the q-axis current and d-axis current are calculated, which are the current-torque angles of the main generator, and then output to the direct torque angle closed-loop control module. The output of the direct torque angle closed-loop control module is connected to the voltage vector control output module. It is used to compare the input current torque angle of the main generator with the direct torque angle closed-loop target torque angle set in this control module. After adjusting the relative angle information between the output voltage vector and the main generator rotor, it is output to the voltage vector control output module to realize the closed-loop regulation of the current direct torque angle of the main generator and realize the control of the d-axis current of the main generator.

8. The starting controller for a three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine as described in claim 6, characterized in that, The input terminal of the three-phase full-bridge inverter is the DC bus voltage and the isolated drive signal of each switch of the three-phase inverter. The output terminal is connected to the three-phase stator winding of the main generator of the three-stage electrically excited synchronous motor. After the rotor of the main generator is excited, the main generator is controlled to realize the motor's electric operation.

9. A control method for a starting controller of a three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine, characterized in that, The starting controller of the three-stage electrically excited synchronous motor, as described in any one of claims 1 to 8, is used to perform starting control on the three-stage electrically excited synchronous motor, the control method comprising: The armature current of the three-phase stator winding of the main generator of the three-stage electrically excited synchronous motor is collected by the indirect current control branch. The effective value of the armature current of the main generator is calculated. In the current speed control cycle, the effective value of the armature current of the main generator is compared with the current limit threshold of the current speed segment. The acceleration control coefficient is output, thereby determining the control amount of increasing speed or decreasing acceleration in the next speed control cycle of the speed closed loop control loop. The position signal of the internal position sensor of the three-stage electrically excited synchronous motor is collected by the acceleration segment control branch, and the relative position and speed of the motor rotor are calculated. Based on the speed range of the motor rotor, the acceleration control quantity corresponding to that speed range is output to the speed closed-loop control loop. The acceleration control quantity output from the acceleration segment control branch and the acceleration control coefficient output from the indirect current control branch are combined and used as the input quantity for the speed control deviation of the speed closed-loop control loop. This keeps the acceleration control quantity relatively fixed under the same motor rotor speed range, thereby preventing sudden changes in the output of the speed closed-loop control loop.

10. The control method for the starting controller of the three-stage electrically excited synchronous motor for low-temperature starting of an aero-engine according to claim 9, characterized in that, Specifically, the steps include the following: Step 1: Start the controller to obtain the actual value of the main generator armature current and the motor rotor position and speed through current acquisition and calculation; Step 2: Perform vector transformation on the armature current of the three-phase main generator to obtain the d-axis current and q-axis current; Step 3: Calculate the effective value of the armature current of the main generator using the effective value of the main generator armature current; Step 4: Calculate the real-time torque angle of the main generator current using the armature current torque angle of the main generator; Step 5: By comparing the current rotor speed with the soft start current closed-loop switching speed, if the current rotor speed is less than or equal to the soft start current loop switching speed, the output voltage vector amplitude is controlled by the soft start current closed-loop and the process proceeds directly to step 9; otherwise, the process proceeds to step 6. Step 6: When the current rotor speed is greater than or equal to the soft start current loop switching speed, the current limit control threshold for this speed segment is obtained through the current limit control module. The effective value of the current armature current of the current main generator is compared with the current limit threshold for this speed segment. If the effective value of the current armature current of the current main generator is greater than the current limit threshold, it is set to deceleration control flag; otherwise, it is set to speed increase control flag. Step 7: By determining the current rotor speed range, obtain the acceleration control quantity corresponding to that speed range through the multi-segment acceleration control module; Step 8: Based on the acceleration control flag determined by the integrated current limiting control module and the acceleration control quantity determined by the multi-segment acceleration control module, the voltage vector amplitude is output through the adjustment of the speed closed-loop control module. Step 9: Adjust the output voltage vector angle through the direct torque angle closed-loop control module, which is the relative angle information between the voltage vector and the main generator rotor; Step 10: By synthesizing the voltage vector magnitude and voltage vector angle, the output is decomposed to obtain the d-axis voltage control quantity and the q-axis voltage control quantity; Step 11: Obtain the α-axis voltage control quantity and β-axis voltage control quantity by performing inverse vector transformation on the d-axis voltage control quantity and the q-axis voltage control quantity; Step 12: The α-axis voltage control quantity and β-axis voltage control quantity are output as control signals for the power switching transistors of the three-phase inverter through SVPWM control.

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