Controllable loss minimization control method for multi-stage starter generator under controllable excitation condition

Abstract

The invention relates to the technical field of motor control, in particular to a controllable loss minimization control method of a multi-stage starter generator under a controllable excitation condition, which comprises the following steps: obtaining controllable loss of a main motor; obtaining controllable loss of the main exciter; obtaining the controllable loss of the rotary integer current converter; obtaining controllable loss of the multi-stage starter generator; and obtaining a target stator shaft magnetization current of the main motor and a target excitation voltage of the main exciter when the controllable loss of the multi-stage starter generator is minimum, and controlling the multi-stage starter generator based on the target stator shaft magnetization current and the target excitation voltage of the main exciter. The controllable loss of the multi-stage motor in the starting process of the aviation main engine is reduced, then the thermal load of the multi-stage motor is reduced, meanwhile, heat accumulation in the starting process is reduced, a starting power generation system is helped to complete the task of starting the aviation main engine, and the continuous starting capacity is improved.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, specifically to a controllable loss minimization control method for a multi-stage starting generator under controllable excitation conditions. Background Technology

[0002] Due to their stable structure and mature power generation technology, multi-stage starter generators can quickly and completely demagnetize in the event of a short-circuit fault, thus preventing fault propagation. Therefore, multi-stage motors have become an important option for achieving integrated start-up and power generation in aviation power systems. During the start-up phase, the high torque demand of the main engine causes multi-stage motors to operate under high overload, resulting in severe heat generation. Improper control methods can lead to excessive starting current, reducing motor lifespan and system reliability, and even causing start-up failure. Therefore, it is necessary to reduce the losses of multi-stage motors during the start-up phase through control methods.

[0003] Existing loss minimization control methods can reduce losses generated during motor operation. For motors operating for extended periods, this improves efficiency, while for motors operating for short periods, it primarily reduces heat generation. Based on the type of loss suppressed, these methods can be categorized into copper loss minimization control (i.e., maximum torque-to-current ratio control), iron loss minimization control, and controllable loss minimization control. Based on their underlying principles, they are mainly divided into search-based control methods, loss model-based control methods, and hybrid search control methods that combine both. Search-based control methods do not depend on motor parameters, but there is a trade-off between search speed and convergence, and they are typically used for motors operating in steady state. Loss model-based control methods, by establishing and solving a loss function, can achieve global loss minimization control.

[0004] During the startup phase, the multistage generator's task is to provide sufficient torque to the aircraft's main engine. The aircraft's main engine has a large moment of inertia, and the high torque demand during startup leads to a large stator current in the main generator, placing the multistage generator under high overload operation and causing significant heat generation during startup. Some aircraft main engines lack forced cooling devices during ground startup, resulting in poor heat dissipation. Improper control methods can lead to excessive starting current in the multistage generator, reducing generator lifespan, decreasing the reliability of the starting generator system, and even causing startup failure. Furthermore, aircraft power systems require the starting generator to be capable of starting the main engine three times consecutively. The significant heat accumulation during startup leads to higher winding temperatures during the second and third startups, increasing the difficulty of continuous startup. Therefore, it is necessary to minimize the losses of the multistage generator while ensuring the aircraft's main engine torque requirements. Current loss minimization control methods mainly focus on induction motors and permanent magnet synchronous motors; loss minimization control methods for electrically excited motors are fewer and usually only apply to single motors with constant excitation current. Compared to these motors, multi-stage motors have more heat-generating components, but at the same time, the excitation voltage of the main exciter and the stator current of the main motor are both controllable, thus having the potential to further reduce controllable losses.

[0005] Therefore, a controllable loss minimization control method for a multi-stage starting generator under controllable excitation conditions is needed to solve the above problems. Summary of the Invention

[0006] To reduce the controllable losses of multi-stage starter generators, this invention provides a control method for minimizing the controllable losses of multi-stage starter generators under controllable excitation conditions, in order to solve existing problems.

[0007] The first aspect of this invention provides a controllable loss minimization control method for a multi-stage starting generator under controllable excitation conditions. This method employs the following technical solution, including: In the rotating coordinate system of the main motor, the sum of the stator iron loss and the rotor iron loss of the main motor is taken as the heat loss of the equivalent iron loss resistance of the main motor; and the direct-axis equivalent circuit and quadrature-axis equivalent circuit of the main motor considering controllable losses are obtained. Based on the direct-axis equivalent circuit and quadrature-axis equivalent circuit of the main motor considering controllable losses, the relationship between the stator current, stator magnetizing current and iron loss current of the main motor is obtained. Based on the relationship between the stator current, stator magnetizing current and iron loss current, the controllable losses of the main motor are transformed into functions of the stator magnetizing current and excitation current of the main motor to obtain the controllable losses of the main motor. In the rotating coordinate system of the main exciter, the sum of the stator iron loss and the rotor iron loss of the main exciter is taken as the heat loss of the equivalent iron loss resistance of the main exciter; and the direct-axis equivalent circuit and quadrature-axis equivalent circuit of the main exciter considering controllable losses are obtained. Based on the three-phase full-wave uncontrolled rectifier formula, the operating characteristic formula of the rotating rectifier is obtained. Based on the direct-axis equivalent circuit and quadrature-axis equivalent circuit of the main exciter, as well as the operating characteristic formula of the rotating rectifier, the relationship between the stator current, stator magnetizing current, iron loss current and main motor excitation current of the main exciter is obtained. Based on the relationship between the stator current, stator magnetizing current, iron loss current and main motor excitation current of the main exciter, the controllable loss of the main exciter is transformed into a function of the main motor excitation current to obtain the controllable loss of the main exciter. The controllable losses of the rotary rectifier are obtained based on the excitation current of the main motor, the forward voltage drop of the diodes in the rotary rectifier, and the equivalent forward resistance. Based on the controllable losses of the main motor, the main exciter, and the rotating rectifier, the controllable losses of the multi-stage starter generator are obtained. Under the constraints of the output capabilities of the main exciter inverter and the main motor inverter, and the starting torque requirements of the aircraft main engine, the target stator of the main motor is calculated to minimize the controllable losses of the multi-stage starter generator. Shaft magnetizing current and target excitation voltage of the main exciter; Based on the target stator The shaft magnetizing current and target excitation voltage are controlled, and the multi-stage starting generator is controlled.

[0008] A further technical solution of the present invention states that the controllable loss of the main motor is a function of the stator magnetizing current and the excitation current of the main motor, and can be expressed as:

[0009]

[0010]

[0011] In the formula, This indicates the controllable losses of the main motor; Indicates the stator winding resistance; Indicates the resistance of the excitation winding; This represents the equivalent iron loss resistance of the main motor; This indicates the electrical angular velocity of the main motor; stator Shaft inductance; stator Shaft inductance; Indicates the stator of the main motor Axis magnetizing current; Indicates the stator of the main motor Axis magnetizing current; Indicates the excitation current; This indicates the magnitude of the mutual inductance between the stator winding and the excitation winding of the main motor; This represents a differential operator.

[0012] A further technical solution of the present invention provides the following operating characteristic formula for the rotating rectifier:

[0013] In the formula, Indicates the transformer coefficient; Indicates the rectification factor. This represents the vector angle between the rotor voltage and rotor current of the main exciter; The excitation current of the main motor; Indicates the main exciter Shaft rotor voltage; Indicates the main exciter Shaft rotor voltage; Indicates the main exciter Shaft rotor current; Indicates the main exciter Shaft rotor current; This indicates the excitation voltage of the main motor.

[0014] A further technical solution of the present invention states that the controllable loss of the main exciter is a function of the excitation current of the main motor, and can be expressed as:

[0015] In the formula, This indicates the controllable losses of the main exciter; The equivalent resistance of the controllable loss of the main exciter; This represents the excitation current of the main motor.

[0016] A further technical solution of the present invention is that the controllable loss of the swirl converter is a function of the excitation current of the main motor, and can be expressed as:

[0017] In the formula, This indicates the controllable losses of the swirl converter; Indicates the excitation current of the main motor; This represents the forward voltage drop of the diode. This represents the equivalent on-resistance.

[0018] A further technical solution of the present invention is that the controllable loss of the multi-stage starter generator is the sum of the controllable loss of the main motor, the controllable loss of the main exciter, and the controllable loss of the rotating rectifier.

[0019] A further technical solution of the present invention is subject to the following constraints: the electromagnetic torque of the multi-stage starter generator is equal to the torque required during the starting process of the aircraft main engine; the stator voltage and stator current of the main motor are within the output capacity range of the main motor inverter; and the stator voltage and stator current of the main exciter are within the output capacity range of the main exciter inverter. These constraints can be expressed as:

[0020] In the formula, This indicates the torque required during the start-up process of an aircraft main engine; This indicates the electromagnetic torque of the main motor; This represents the electromagnetic torque of the main exciter; This indicates the electrical angular velocity of the main motor; Indicates the main motor Shaft stator flux linkage; Indicates the main motor Shaft stator flux linkage; Indicates the main exciter Shaft stator flux linkage; Indicates the main exciter Shaft stator flux linkage; This represents the magnitude of the maximum voltage vector that the main motor inverter can provide; This indicates the magnitude of the maximum voltage vector that the main exciter inverter can provide; This indicates the magnitude of the maximum current vector that the main motor inverter can provide; This represents the magnitude of the maximum current vector that the main exciter inverter can provide; corresponding to the magnitudes of the maximum voltage vector and current vector that the main motor and main exciter inverter can provide. Indicates the main motor Shaft stator current; Indicates the main motor Shaft stator current; Indicates the main exciter Shaft stator current; Indicates the main exciter Shaft stator current.

[0021] A further technical solution of the present invention, under the constraints of the output capacity of the main exciter inverter and the main motor inverter, and the starting torque required by the aircraft main engine, solves for the target stator of the main motor that minimizes the controllable losses of the multi-stage starter generator. The steps for determining the shaft magnetizing current and the target excitation voltage of the main exciter are as follows: By establishing the Lagrangian function and based on the KKT conditions, the minimum controllable loss operating point of the multi-stage motor can be obtained as the solution to the following equation:

[0022] The solution is obtained iteratively using a first-order Taylor expansion, with the initial value calculated as follows:

[0023] In the formula, This represents the iterative function used to calculate the operating point with minimum controllable loss; Represents the coefficient of the sixth term of the iterative function; Represents the coefficient of the fifth term in the iterative function; Represents the coefficient of the fourth term in the iterative function; Represents the coefficient of the cubic term in the iterative function; This represents the coefficient of the quadratic term in the iterative function; This represents the coefficient of the first-order term of the iterative function; Represents the constant term of the iterative function; This represents the constant term of the iterative function; Let represent the independent variable of the iterative function; This represents the initial value used for the iteration to calculate the operating point with minimum controllable loss; This indicates the electrical angular velocity of the main motor; stator Shaft inductance; stator Shaft inductance; Indicates the stator winding resistance; Represents the equivalent iron loss resistance; during the iteration process, the relationship between the (k+1)th operating point and the kth operating point is: Based on this, the operating point corresponding to the minimum controllable loss of the multi-stage starter generator can be obtained. This leads to the corresponding target excitation voltage of the main exciter and the target stator voltage of the main motor. Axial magnetizing current.

[0024] A second aspect of the present invention provides a controllable loss minimization control system for a multi-stage starter generator under controllable excitation conditions, comprising: The main motor controllable loss acquisition module is used to obtain the heat loss of the main motor by taking the sum of the stator iron loss and rotor iron loss of the main motor as the equivalent iron loss resistance in the rotating coordinate system of the main motor; and to obtain the direct-axis equivalent circuit and quadrature-axis equivalent circuit of the main motor considering controllable losses; based on the direct-axis equivalent circuit and quadrature-axis equivalent circuit of the main motor considering controllable losses, the module obtains the relationship between the stator current, stator magnetizing current and iron loss current of the main generator; and based on the relationship between the stator current, stator magnetizing current and iron loss current, the module transforms the controllable loss of the main motor into a function of the stator magnetizing current and excitation current of the main motor to obtain the controllable loss of the main motor. The controllable loss acquisition module for the main exciter is used to obtain the heat loss of the main exciter by taking the sum of the stator iron loss and rotor iron loss of the main exciter as the equivalent iron loss resistance in the rotating coordinate system of the main exciter; and to obtain the direct-axis equivalent circuit and quadrature-axis equivalent circuit of the main exciter considering controllable losses; based on the three-phase full-wave uncontrolled rectification formula, the operating characteristic formula of the rotating rectifier is obtained; based on the direct-axis equivalent circuit and quadrature-axis equivalent circuit of the main exciter, as well as the operating characteristic formula of the rotating rectifier, the relationship between the stator current, stator magnetizing current, iron loss current and main motor excitation current of the main exciter is obtained; based on the relationship between the stator current, stator magnetizing current, iron loss current and main motor excitation current of the main exciter, the controllable loss of the main exciter is transformed into a function of the main motor excitation current to obtain the controllable loss of the main exciter; The controllable loss acquisition module of the rotating rectifier is used to obtain the controllable loss of the rotating rectifier based on the excitation current of the main motor and the forward voltage drop and equivalent on-resistance of the diodes in the rotating rectifier. The controllable loss acquisition module for multi-stage starter generator is used to acquire the controllable loss of multi-stage starter generator based on the controllable loss of main motor, controllable loss of main exciter and controllable loss of rotating rectifier. The minimum controllable loss solution module is used to obtain the controllable losses of the multi-stage starter generator based on the controllable losses of the main motor, the main exciter, and the rotating rectifier. Under the constraints of the output capabilities of the main exciter inverter and the main motor inverter, and the starting torque requirements of the aircraft main engine, it solves for the target stator of the main motor that minimizes the controllable losses of the multi-stage starter generator. Shaft magnetizing current and target excitation voltage of main exciter

[0025] Control module, used for target stator The shaft magnetizing current and target excitation voltage are controlled, and the multi-stage starting generator is controlled.

[0026] A third aspect of the present invention provides a storage medium including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of a controllable loss minimization control method for a multi-stage starting generator under controllable excitation conditions according to the present invention.

[0027] The beneficial effects of this invention are: This invention proposes a method for minimizing the controllable losses of a multi-stage starter generator under controllable excitation conditions. By defining the controllable losses of the main motor, the main exciter, and the rotating rectifier, the controllable losses of the multi-stage starter generator are obtained. Under the constraints of the output capabilities of the main exciter inverter and the main motor inverter, as well as the starting torque requirement of the aircraft main engine, the target stator of the main motor is obtained by solving for the minimum controllable losses of the multi-stage starter generator. Shaft magnetizing current and target excitation voltage of main exciter, based on target stator By controlling the shaft magnetizing current and target excitation voltage, the multi-stage motor can ensure that the multi-stage starter generator provides the torque required by the aircraft main engine while minimizing controllable losses. This reduces the controllable losses of the multi-stage motor during the aircraft main engine start-up process, thereby reducing the thermal load on the multi-stage motor and minimizing heat accumulation during startup. This helps the starter generator system complete the task of starting the aircraft main engine and improves the ability to start continuously. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart illustrating an embodiment of the controllable loss minimization control method for a multi-stage starting generator under controllable excitation conditions according to the present invention. Figure 2 This is a schematic diagram of the specific process of a controllable loss minimization control method for a multi-stage starting generator under controllable excitation conditions according to the present invention. Figure 3 This is a schematic diagram of a multi-stage starting and generating system based on a two-phase main exciter in an embodiment of the present invention; Figure 4 This is a schematic diagram of the direct-axis equivalent circuit and quadrature-axis equivalent circuit of the main motor considering controllable losses in an embodiment of the present invention; Figure 5 This is a schematic diagram of the direct-axis equivalent circuit and quadrature-axis equivalent circuit of the main exciter considering controllable losses in an embodiment of the present invention; Figure 6 This is a graph showing the correlation function of the minimum controllable loss operating point in an embodiment of the present invention. Figure 7 The diagram shows the control effect of different methods during steady-state operation of a multi-stage motor in the embodiments of the present invention. Figure 8This is a comparison chart showing the control effects of the method (CELMC) of this invention embodiment and the existing controllable loss minimization control method (UELMC) during the startup process. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] This invention provides an embodiment of a controllable loss minimization control method for a multi-stage starting generator under controllable excitation conditions. The embodiment uses... Figure 3 The following is an example of a typical multi-stage starting and generating system based on a two-phase main exciter. This invention is also applicable to multi-stage starting and generating systems based on a three-phase main exciter. Specifically... Figure 3 The system shown is as follows: Figure 1 and Figure 2 As shown, the specific steps of the method for minimizing the controllable losses of a multi-stage starting generator under controllable excitation conditions are as follows: S1. Obtain the controllable losses of the main motor; Specifically, in the rotating coordinate system of the main motor, the sum of the stator iron loss and rotor iron loss of the main motor is taken as the heat loss of the equivalent iron loss resistance of the main motor; and the direct-axis equivalent circuit and quadrature-axis equivalent circuit of the main motor considering controllable losses are obtained; based on the direct-axis equivalent circuit and quadrature-axis equivalent circuit of the main motor considering controllable losses, the relationship between the stator current, stator magnetizing current and iron loss current of the main motor is obtained; based on the relationship between the stator current, stator magnetizing current and iron loss current, the controllable losses of the main motor are transformed into functions of the stator magnetizing current and excitation current of the main motor to obtain the controllable losses of the main motor.

[0032] The basic expression for the controllable losses of the main motor is:

[0033] In the formula, This indicates the controllable losses of the main motor; This indicates the stator copper loss of the main motor; This indicates the rotor copper loss of the main motor; This indicates the iron loss of the main motor; Indicates the stator winding resistance; Indicates the resistance of the excitation winding; Represents the equivalent iron loss resistance; Indicates the main motor Shaft stator current; Indicates the main motor Shaft stator current; Indicates the excitation current; express Shaft iron loss current; express Shaft iron loss current.

[0034] The controllable losses of the aforementioned basic main motor are functions of the stator current, excitation current, and iron loss current. The task of the multi-stage motor during startup is to generate the electromagnetic torque required by the aircraft main engine, and the stator magnetizing current and excitation current are directly related to this electromagnetic torque. Loss minimization control aims to control the multi-stage motor and reduce its losses while meeting the torque requirements of the aircraft main engine. The aforementioned basic controllable loss function of the main motor does not directly reflect the stator magnetizing current, and therefore cannot be directly applied to the control strategy. Therefore, it is necessary to express the stator current and iron loss current of the main motor in terms of the stator magnetizing current, thereby transforming the basic controllable loss function into a function of the stator magnetizing current and excitation current. Thus, this embodiment uses the main motor stator magnetizing current and excitation current as controlled variables. In subsequent stages, it is possible to find the combination of main motor stator magnetizing current and excitation current that minimizes the controllable loss function value among combinations of main motor stator magnetizing current and excitation current that produce the same electromagnetic torque.

[0035] In this embodiment, in the synchronous rotating orthogonal coordinate system of the main motor, the sum of the stator iron loss and rotor iron loss of the main motor is equivalent to the equivalent iron loss resistance of the main motor. The heat loss, considering the controllable losses of the main motor direct shaft ( (axis) equivalent circuit such as Figure 4 (a) shows the intersection axis ( (axis) equivalent circuit such as Figure 4 As shown in (b), the relationship between the stator current, stator magnetizing current, and iron loss current of the main motor can be obtained. Furthermore, the controllable losses of the main motor can be transformed into a function of the stator magnetizing current and excitation current. Therefore, the expression for the controllable losses of the main motor in this embodiment is:

[0036] In the formula, This indicates the controllable losses of the main motor; Indicates the stator winding resistance; Indicates the resistance of the excitation winding; This represents the equivalent iron loss resistance of the main motor; This indicates the electrical angular velocity of the main motor; stator Shaft inductance; stator Shaft inductance; Indicates the stator of the main motor Axis magnetizing current; Indicates the stator of the main motor Axis magnetizing current; Indicates the excitation current; This indicates the magnitude of the mutual inductance between the stator winding and the excitation winding of the main motor; This represents a differential operator.

[0037] S2. Obtain the controllable losses of the main exciter; Specifically, in the rotating coordinate system of the main exciter, the sum of the stator iron loss and rotor iron loss of the main exciter is taken as the heat loss of the equivalent iron loss resistance of the main exciter; and the direct-axis equivalent circuit and quadrature-axis equivalent circuit of the main exciter considering controllable losses are obtained; according to the three-phase full-wave uncontrolled rectification formula, the operating characteristic formula of the rotating rectifier is obtained; according to the direct-axis equivalent circuit and quadrature-axis equivalent circuit of the main exciter, as well as the operating characteristic formula of the rotating rectifier, the relationship between the stator current, stator magnetizing current, iron loss current and main motor excitation current of the main exciter is obtained; based on the relationship between the stator current, stator magnetizing current, iron loss current and main motor excitation current of the main exciter, the controllable losses of the main exciter are transformed into a function of the main motor excitation current to obtain the controllable losses of the main exciter.

[0038] The expression for the controllable losses of the basic main exciter is:

[0039] In the formula, This indicates the controllable losses of the main exciter; This indicates the stator copper loss of the main exciter; This indicates the rotor copper loss of the main exciter; This indicates the iron loss of the main exciter motor; Indicates the resistance of the excitation winding; Indicates the armature winding resistance; Represents the equivalent iron loss resistance; Indicates the main exciter Shaft stator current; Indicates the main exciter Shaft stator current; Indicates the main exciter Shaft rotor current; Indicates the main exciter Shaft rotor current; express Shaft iron loss current; express Shaft iron loss current.

[0040] In S1, the stator magnetizing current and excitation current of the main motor have been selected as controlled variables. The basic controllable losses of the main exciter described above are functions of the stator current, rotor current, and iron loss current of the main exciter, but do not include the selected controlled variables; therefore, they cannot be directly applied to the control strategy. During startup, the core function of the main exciter is to provide excitation current to the main motor in conjunction with the rotating rectifier. Therefore, it is necessary to express the stator current, rotor current, and iron loss current of the main exciter using the excitation current of the main motor, thereby transforming the basic controllable loss function of the main exciter into a function of the excitation current of the main motor.

[0041] Therefore, in this embodiment, the ratio of the amplitude of the main exciter's excitation voltage to the main motor's excitation current is first defined as the equivalent resistance of the excitation system. Based on the multi-stage motor rotor-side current estimation algorithm, the main motor excitation current during startup can be obtained. This can then be combined with the amplitude of the main exciter's excitation voltage to... Perform the calculation.

[0042]

[0043] In the formula, Indicates the amplitude of the main exciter's excitation voltage; This represents the equivalent resistance of the excitation system; This represents the excitation current of the main motor.

[0044] For example, in one specific embodiment, based on the three-phase full-wave uncontrolled rectifier formula, ignoring the effects of parasitic resistance and capacitance, the operating characteristic formula of the rotating rectifier is as follows:

[0045] In the formula, Indicates the transformer coefficient; Indicates the rectification factor. This represents the vector angle between the rotor voltage and rotor current of the main exciter; Indicates the excitation current of the main motor; Indicates the main exciter Shaft rotor voltage; This represents the q-axis rotor voltage of the main exciter; Indicates the main exciter Shaft rotor current; Indicates the main exciter Shaft rotor current; This indicates the excitation voltage of the main motor.

[0046] For example, in one specific embodiment, in an orthogonal coordinate system that rotates synchronously with the excitation magnetic field of the main exciter, the sum of the stator iron loss and rotor iron loss of the main exciter is equivalent to the equivalent iron loss resistance of the main exciter. The heat loss, considering the controllable losses of the direct shaft of the main exciter ( (axis) equivalent circuit such as Figure 5 (a) shows the intersection axis ( (axis) equivalent circuit such as Figure 5 As shown in (b). Based on the equivalent circuits of the direct-axis and quadrature-axis main exciter and the operating characteristic formulas of the rotating rectifier, the relationships between the stator current, stator magnetizing current, iron loss current, and excitation current of the main exciter can be obtained. Furthermore, the controllable losses of the main exciter can be transformed into a function of the excitation current of the main motor. Therefore, the expression for the controllable loss function of the main exciter is:

[0047] In the formula, This indicates the controllable losses of the main exciter; This represents the excitation current of the main motor; The derived coefficient is defined as the equivalent resistance of the controllable loss of the main exciter. It is calculated using the inductance, resistance, and electrical angular velocity of the main exciter, as well as the transformer coefficient and rectification coefficient of the rotating rectifier. Its expression is as follows:

[0048] In the formula, This represents the equivalent resistance of the controllable losses of the main exciter; Indicates the resistance of the excitation winding; Indicates the armature winding resistance; This represents the equivalent iron loss resistance of the main exciter; This represents the equivalent resistance of the excitation system; Indicates the first intermediate quantity; Indicates the second intermediate quantity; Indicates the third intermediate quantity; Indicates the fourth intermediate quantity; Indicates the fifth intermediate quantity; Indicates the sixth intermediate quantity; Indicates the seventh intermediate quantity; Indicates the eighth intermediate quantity; This represents the ninth intermediate quantity. These intermediate quantities are only related to the inductance, resistance, and electrical angular velocity of the main exciter.

[0049] The intermediate quantity expression is as follows:

[0050] In the formula, The electric angular velocity of the excitation magnetic field of the main exciter; The electric angular velocity of the main exciter rotor; The self-inductance of the excitation winding; This is the self-inductance of the armature winding; This represents the amplitude of the mutual inductance between the excitation winding and the armature winding; , , , , , , , All are intermediate values.

[0051] S3. Obtain the controllable losses of the swirl converter; Specifically, the controllable losses of the rotating rectifier are obtained based on the excitation current, the forward voltage drop of the diodes in the rotating rectifier, and the equivalent on-resistance. In this embodiment, the expression for the controllable losses of the rotating rectifier is:

[0052] In the formula, This indicates the controllable losses of the swirl converter; Indicates the excitation current of the main motor; This represents the forward voltage drop of the diode. This represents the equivalent on-resistance.

[0053] S4. Obtain the controllable losses of a multi-stage starter generator; Specifically, based on the controllable losses of the main motor, the main exciter, and the rotating rectifier, the controllable losses of the multi-stage starter generator are obtained. Since the current has been unified in the previous steps, the obtained controllable losses of the multi-stage starter generator are functions of the main motor stator magnetizing current and the excitation current.

[0054] For example, in one specific embodiment, the sum of the controllable losses of the main motor, the controllable losses of the main exciter, and the controllable losses of the rotating rectifier is taken as the controllable losses of the multi-stage starter generator, wherein the expression for the controllable losses of the multi-stage starter generator is:

[0055] S5. Obtain the target stator of the main motor when the controllable losses of the multi-stage starter generator are minimized. Shaft magnetizing current and target excitation voltage of the main exciter; Specifically, under the constraints of the output capacity of the main exciter inverter and the main motor inverter, as well as the starting torque required by the aircraft main engine, we solve for the target stator of the main motor that minimizes the controllable losses of the multi-stage starter generator. Shaft magnetizing current and target excitation voltage of main exciter.

[0056] For example, in one specific embodiment, the constraint is:

[0057] In the formula, This indicates the torque required during the start-up process of an aircraft main engine; This indicates the electromagnetic torque of the main motor; This represents the electromagnetic torque of the main exciter; This indicates the electrical angular velocity of the main motor; Indicates the main motor Shaft stator flux linkage; Indicates the main motor Shaft stator flux linkage; Indicates the main exciter Shaft stator flux linkage; Indicates the main exciter Shaft stator flux linkage; This represents the magnitude of the maximum voltage vector that the main motor inverter can provide; This indicates the magnitude of the maximum voltage vector that the main exciter inverter can provide; This indicates the magnitude of the maximum current vector that the main motor inverter can provide; This represents the magnitude of the maximum current vector that the main exciter inverter can provide; corresponding to the magnitudes of the maximum voltage vector and current vector that the main motor and main exciter inverter can provide. Indicates the main motor Shaft stator current; Indicates the main motor Shaft stator current; Indicates the main exciter Shaft stator current; Indicates the main exciter Shaft stator current.

[0058] Among them, the electromagnetic torque of the main motor It can be represented as:

[0059] In the formula, and The stator flux linkage of the main motor The number of pole pairs of the main motor.

[0060] Among them, the electromagnetic torque of the main exciter It can be represented as:

[0061] In the formula, and The rotor flux linkage of the main exciter. The number of pole pairs of the main exciter. The coefficients obtained from the derivation are defined as the equivalent inductance of the main exciter.

[0062]

[0063] To find the target stator of the main motor that minimizes the controllable losses of a multi-stage starter generator under constraints. The shaft magnetizing current and the target excitation voltage of the main exciter (defined as the motor operating at the point of minimum controllable loss) are used to establish the following Lagrangian functions based on mathematical optimization methods:

[0064] In the formula, For Lagrange multipliers with equality constraints, For the Lagrange multipliers constrained by the first inequality, For the Lagrange multipliers constrained by the second inequality, For the Lagrange multipliers constrained by the third inequality, For the Lagrange multipliers constrained by the fourth inequality.

[0065] According to the KKT conditions in the optimization methods branch of applied mathematics, the constraint expression for the minimum controllable loss operating point is:

[0066] In the formula, , , , All are intermediate values, and the expressions for the intermediate values ​​are:

[0067] In the formula, , , , , All are intermediate quantities; For equality-bound Lagrange multipliers.

[0068] Based on the constraints satisfied by the minimum controllable loss operating point, the solution to the following equation for the minimum controllable loss operating point of a multi-stage motor can be derived:

[0069] In the formula, the intermediate quantities satisfy the expression:

[0070] The univariate sixth-degree equation satisfied by the minimum controllable loss operating point of the aforementioned multi-stage motor can be solved iteratively. Considering that the univariate sixth-degree equation usually has multiple solutions, but not every solution is a reasonable operating point, a graphical method can be used for troubleshooting.

[0071] For ease of explanation, a function is defined. The minimum controllable loss operating point of the multi-stage motor is given by equation [equation missing]. The solution.

[0072] In acquiring Based on the function expression, the graph of the function can be plotted, and the intersection points of the graph with the x-axis can be observed. These intersection points satisfy... Therefore, this is a possible solution for the minimum controllable loss operating point of a multi-stage motor.

[0073] Furthermore, referring to the constraints satisfied by the minimum controllable loss operating point obtained from the KKT conditions, the main motor excitation current corresponding to the minimum controllable loss operating point satisfies the following set of equations:

[0074] For ease of explanation, a function is defined. and Then the main motor excitation current corresponding to the minimum controllable loss operating point satisfies .

[0075]

[0076] In acquiring and Based on the function expressions, we can plot the graphs of two functions and then observe their intersection points, which satisfy... Therefore, this is a possible solution for the minimum controllable loss operating point of a multi-stage motor. That is, since the minimum controllable loss operating point of a multi-stage motor satisfies... And satisfied Therefore, it can be accessed through , and The graph is used to comprehensively judge the possible solutions for the minimum controllable loss operating point of a multi-stage motor.

[0077] It should be noted that in obtaining , and In the case of an expression, a numeric calculator can be used to iterate through the independent variable x and calculate the values ​​corresponding to different x. , and The function value is used to quickly obtain possible solutions for the minimum controllable loss operating point. Then, based on the sign and order of magnitude of the main motor excitation current and main exciter voltage amplitude corresponding to these operating points, the possible solutions are filtered to obtain the true minimum controllable loss operating point. However, the processors of commonly used motor controllers do not possess the fast computing power of digital computers. Therefore, the traversal solution method cannot quickly obtain the true minimum controllable loss operating point within a control cycle. Thus, it is still necessary to directly provide a method for calculating the true minimum controllable loss operating point. The key is to select a suitable initial value for iteration, which ensures that the operating point obtained after iterative calculation is the true minimum controllable loss operating point. This initial value is used... The expression for the initial value of the iteration is:

[0078] The following example illustrates the use of the formula calculated above. As an initial value for iteration, it can make the iteration results converge to the true minimum controllable loss operating point.

[0079] For the multi-stage motor used as an example, when the multi-stage motor is operating in steady state at 2000 r / min and 150 Nm, the function is plotted. , and The graphic, and according to The intersection points with the x-axis are used to filter the main motor excitation current, the sign and order of magnitude of the main exciter excitation voltage amplitude, and the points where they intersect the x-axis, thus obtaining the true minimum controllable loss operating point, defined as point P. Function , and The graph of point P and its surrounding area is as follows: Figure 6 As shown. Point Q is the spurious minimum controllable loss operating point adjacent to point P, meaning that although it satisfies... , However, the main motor excitation current or main exciter excitation voltage corresponding to point Q is not within the normal operating range of the motor.

[0080] by Figure 6 Taking the region shown as an example, to obtain the true minimum controllable loss operating point P, iteration must begin to the left of point P. If the initial value of the iteration is to the right of point Q, the iteration result will converge to point Q, a false minimum controllable loss operating point. However, if the initial value of the iteration is between point P and point Q, the iteration result also has the possibility of converging to point Q. As can be seen from the graph, to the left of point P, as... The decrease, It will approach the horizontal coordinate axis infinitely. Therefore, we can choose one that satisfies... And the working point N, located to the left of point P, is used as the initial value for iteration; when obtaining the initial value for iteration... Based on this, iterative processes can be performed using Taylor series expansion to gradually approach the working point from point N to point P. Specifically, at point N... A first-order Taylor expansion yields... Solving for the given information yields the following results: This is the first iteration calculation. This corresponds to the working point after the first iteration. The relationship between the (k+1)th working point and the kth working point is as follows: Based on this, iterative steps can be taken to obtain the minimum controllable loss operating point of the multi-stage motor. .

[0081] For the multi-stage motor used as an example, when the multi-stage motor is operating in steady state at 2000 r / min and 150 Nm, the iterative calculation results are shown in Table 1.

[0082] Table 1

[0083] It can be seen that the minimum loss operating point P can be obtained after approximately five iterations of calculation. Then, the x corresponding to point P is substituted into... The expression can be used to obtain the main motor excitation current corresponding to point P, and then substitute it into... The target excitation voltage of the main exciter corresponding to point P can be obtained, and then substituted into... The target stator of the main motor corresponding to point P can be obtained. Axial magnetizing current.

[0084] S6, Based on target stator Shaft magnetizing current and target excitation voltage are used to control multi-stage motors; Specifically, based on the target stator The shaft magnetizing current and target excitation voltage are used to control a multi-stage motor.

[0085] The reference excitation voltage is set according to the target excitation voltage of the main exciter corresponding to the minimum controllable loss operating point, and the target stator voltage of the main motor is set according to the minimum controllable loss operating point. The direct-axis magnetizing current sets the reference current for the direct-axis current loop PI regulator. Based on the principle of vector control, the output of the speed loop PI regulator is the stator quadrature-axis magnetizing current corresponding to the minimum loss operating point. The inverters of the main motor and the main exciter drive the multi-stage motor to follow the minimum controllable loss operating point, thereby achieving controllable loss minimization control of the multi-stage motor during the start-up phase.

[0086] The following description, in conjunction with the accompanying drawings and experimental data, illustrates this embodiment: When multi-stage motors are used When the control method operates steadily at 900 r / min and 30 Nm, the control method is switched from [presumably a control method] at 10 s. The method was switched to the copper loss minimization control method. At 20 seconds, the control method was switched from the copper loss minimization control method to the controllable loss minimization control method under uncontrolled excitation conditions. At 30 seconds, the control method was switched from the controllable loss minimization control method under uncontrolled excitation conditions to the method of this invention. The experimental results are as follows. Figure 7 As shown. Among them, Figure 7 (a) A schematic diagram of the stator direct-axis current, quadrature-axis current and the effective value of the stator current vector of the main motor; Figure 7 (b) A schematic diagram of the effective value of the excitation voltage of the main exciter; Figure 7 (c) A schematic diagram of the stator input power of the main exciter; Figure 7 (d) A schematic diagram of the stator input power of the main motor and the multi-stage motor, wherein the stator input power of the multi-stage motor is the sum of the stator input power of the main exciter and the stator input power of the main motor; from Figure 7 (b) It can be seen that when the excitation voltage of the main exciter is also treated as a controllable variable, the method of the present invention increases the excitation voltage of the main motor from 60V to 79V. Figure 7 (c) It can be seen that the change in the excitation voltage of the main exciter leads to an increase in the stator input power of the main exciter. Furthermore, due to… Figure 7 (a) It can be seen that the stator current of the main motor also changes accordingly, such as Figure 7 (d) It can be seen that the stator input power of the main motor decreases, and the stator input power of the multi-stage motor also decreases. Since the motor speed and torque remain constant, the decrease in the stator input power of the multi-stage motor indicates a reduction in the controllable losses of the multi-stage motor. Therefore, it can be seen that the multi-stage motor has a greater ability to reduce controllable losses. The control method, the copper loss minimization control method, the controllable loss minimization control method under uncontrolled excitation conditions, and the method of the present invention are successively enhanced, that is, the present invention can more effectively reduce the controllable loss of multi-stage starter generators.

[0087] The starting process of a multi-stage motor was controlled using the Uncontrolled Loss Minimization Control (UELMC) method under uncontrolled excitation conditions and the method of this invention (CELMC). The experimental results are as follows: Figure 8 As shown. Figure 8 (a) is a schematic diagram of the effective values ​​of the main motor stator direct-axis current, quadrature-axis current and stator current vector corresponding to the UELMC method and the CELMC method; Figure 8 (b) is a schematic diagram of the effective values ​​of the excitation voltage of the main exciter corresponding to the UELMC method and the CELMC method; Figure 8(c) is a schematic diagram of the stator input power of the main exciter corresponding to the UELMC and CELMC methods. Figure 8 (b) It can be seen that the UELMC method does not control the excitation voltage of the main exciter, therefore the excitation voltage of the main exciter remains constant, while the CELMC method continuously adjusts the excitation voltage of the main exciter as the speed and torque change. Because the excitation voltage of the main exciter changes, the stator current of the main motor also exhibits a linear relationship. Figure 8 The change is shown in (a). From Figure 8 (c) It can be seen that, at the same moment during the startup process (i.e., under the same speed and torque conditions), the method of the present invention requires less stator input power for the multi-stage motor. When the two methods are used for control during startup, the energy provided by the inverter to the multi-stage motor is approximately 96.0 kJ and 92.9 kJ, respectively, indicating that the method of the present invention can effectively reduce controllable losses during startup.

[0088] This embodiment also provides a controllable loss minimization control system for a multi-stage starter generator under controllable excitation conditions, including: a controllable loss acquisition module for the main motor, a controllable loss acquisition module for the main exciter, a controllable loss acquisition module for the rectifier, a controllable loss acquisition module for the multi-stage starter generator, and a control module. The controllable loss acquisition module for the main motor is used to take the sum of the stator iron loss and rotor iron loss of the main motor as the heat loss of the equivalent iron loss resistance of the main motor in the rotating coordinate system of the main motor; and to acquire the direct-axis equivalent circuit and quadrature-axis equivalent circuit of the main motor considering controllable losses; based on the direct-axis of the main motor considering controllable losses... Equivalent circuits and quadrature-axis equivalent circuits are used to obtain the relationship between the stator current, stator magnetizing current, and iron loss current of the main generator. Based on this relationship, the controllable losses of the main generator are transformed into functions of the stator magnetizing current and excitation current to obtain the controllable losses of the main generator. The controllable loss acquisition module of the main exciter is used to take the sum of the stator iron loss and rotor iron loss of the main exciter as the heat loss of the equivalent iron loss resistance of the main exciter in the rotating coordinate system of the main exciter. It also obtains the direct-axis equivalent circuit and quadrature-axis equivalent circuit of the main exciter considering the controllable losses. According to the three-phase full-wave uncontrolled rectification formula, the controllable losses are obtained. The operating characteristic formula of the rotating rectifier is used. Based on the direct-axis and quadrature-axis equivalent circuits of the main exciter, and the operating characteristic formula of the rotating rectifier, the relationship between the stator current, stator magnetizing current, iron loss current, and main motor excitation current of the main exciter is obtained. Based on this relationship, the controllable losses of the main exciter are transformed into a function of the main motor excitation current to obtain the controllable losses of the main exciter. The controllable loss acquisition module of the rotating rectifier is used to obtain the controllable losses based on the main motor excitation current and the forward voltage drop and equivalent on-resistance of the diodes in the rotating rectifier. The controllable losses of the rotating rectifier are calculated. A module for obtaining the controllable losses of the multi-stage starter generator is used to obtain the controllable losses of the multi-stage starter generator based on the controllable losses of the main motor, the main exciter, and the rotating rectifier. A module for solving for the minimum controllable losses is used to obtain the controllable losses of the multi-stage starter generator based on the controllable losses of the main motor, the main exciter, and the rotating rectifier. Under the constraints of the output capabilities of the main exciter inverter and the main motor inverter, and the starting torque requirement of the aircraft main engine, the target stator of the main motor is solved to minimize the controllable losses of the multi-stage starter generator. Shaft magnetizing current and target excitation voltage of main exciter The control module is used for target stator The shaft magnetizing current and target excitation voltage are controlled, and the multi-stage starting generator is controlled.

[0089] This embodiment also provides a storage medium, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, it implements the steps of the controllable loss minimization control method for a multi-stage starting generator under controllable excitation conditions according to the present invention.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A controllable loss minimization control method for a multi-stage starting generator under controllable excitation conditions, characterized by, Comprise: In the rotating coordinate system of the main motor, the sum of the stator iron loss and the rotor iron loss of the main motor is taken as the heat loss of the equivalent iron loss resistance of the main motor; and the direct-axis equivalent circuit and the quadrature-axis equivalent circuit of the main motor considering the controllable loss are obtained; Based on the direct-axis equivalent circuit and the quadrature-axis equivalent circuit of the main motor considering the controllable loss, the relationship among the stator current, the stator magnetizing current and the iron loss current of the main motor is obtained, and the controllable loss of the main motor is converted into a function about the stator magnetizing current and the excitation current of the main motor to obtain the controllable loss of the main motor; In the rotating coordinate system of the main excitation motor, the sum of the stator iron loss and the rotor iron loss of the main excitation motor is taken as the heat loss of the equivalent iron loss resistance of the main excitation motor; and the direct-axis equivalent circuit and the quadrature-axis equivalent circuit of the main excitation motor considering the controllable loss are obtained; According to the three-phase full-wave uncontrolled rectification formula, the working characteristic formula of the rotary rectifier is obtained, and according to the direct-axis equivalent circuit and the quadrature-axis equivalent circuit of the main excitation motor and the working characteristic formula of the rotary rectifier, the relationship among the stator current, the stator magnetizing current, the iron loss current and the excitation current of the main motor of the main excitation motor is obtained; Based on the relationship among the stator current, the stator magnetizing current, the iron loss current and the excitation current of the main motor of the main excitation motor, the controllable loss of the main excitation motor is converted into a function about the excitation current of the main motor to obtain the controllable loss of the main excitation motor; According to the excitation current and the conduction voltage drop and the equivalent conduction resistance of the diode in the rotary rectifier, the controllable loss of the rotary rectifier is obtained; According to the controllable loss of the main motor, the controllable loss of the main excitation machine and the controllable loss of the rotary rectifier, the controllable loss of the multi-stage starting generator is obtained; under the constraint conditions of the output capacity of the main excitation machine inverter and the main motor inverter and the starting demand torque of the aero-engine, the target stator magnetization current of the shaft and the target excitation voltage of the main excitation machine are solved when the controllable loss of the multi-stage starting generator is minimum. Target stator based The shaft magnetizing current and the target field voltage are controlled and a multi-stage starter-generator is controlled.

2. A controllable loss minimization control method of a multi-stage starting generator under controllable excitation conditions according to claim 1, characterized in that, The controllable loss of the main motor is a function of the stator magnetizing current and the excitation current of the main motor, and can be expressed as: wherein represents the controllable losses of the main electric machine; represents the stator winding resistance; represents the field winding resistance; represents the equivalent iron loss resistance of the main electric machine; represents the electrical angular velocity of the main electric machine; represents the stator axial inductance; represents the stator axial inductance; represents the stator axial magnetizing current; represents the stator axial magnetizing current; represents the field current; represents the amplitude of the mutual inductance between the main electric machine stator winding and the field winding; represents the differential operator.

3. A controllable loss minimization control method of a multi-stage starting generator under controllable excitation conditions according to claim 1, characterized in that, The working characteristic formula of the rotary rectifier is: wherein represents a voltage coefficient of the main motor; represents a rectification coefficient, represents a vector angle of the rotor voltage and the rotor current of the main exciter; represents an excitation current of the main motor; represents a voltage coefficient of the main exciter; represents a voltage coefficient of the main exciter; represents a voltage coefficient of the main exciter; represents a voltage coefficient of the main exciter; represents a current coefficient of the main exciter; represents a current coefficient of the main exciter; represents a current coefficient of the main exciter; represents a current coefficient of the main exciter; represents an excitation voltage of the main motor.

4. A controllable loss minimization control method of a multi-stage starting generator under controllable excitation conditions according to claim 1, characterized in that, The controllable loss of the main excitation motor is a function of the excitation current of the main motor, and can be expressed as: wherein represents the controllable losses of the main exciter; is the equivalent resistance of the controllable losses of the main exciter; represents the field current of the main motor.

5. A controllable loss minimization control method of a multi-stage starting generator under controllable excitation conditions according to claim 1, characterized in that, The controllable loss of the rotary rectifier is a function of the excitation current of the main motor, and can be expressed as: wherein represents the controllable losses of the rotary electrical machine; represents the main electrical machine excitation current; represents the diode conduction voltage drop, represents the equivalent conduction resistance.

6. A controllable loss minimization control method of a multi-stage starting generator under controllable excitation conditions according to claim 1, characterized in that, The controllable loss of the multi-stage starting generator is the sum of the controllable loss of the main motor, the controllable loss of the main excitation motor and the controllable loss of the rotary rectifier.

7. A controllable loss minimization control method of a multi-stage starting generator under controllable excitation conditions according to claim 1, characterized in that, The constraint condition is that the electromagnetic torque of the multi-stage starting generator is equal to the required torque in the starting process of the aero-engine main engine; the stator voltage and the stator current of the main motor are within the output capability range of the main motor inverter; and the stator voltage and the stator current of the main excitation motor are within the output capability range of the main excitation motor inverter, i.e. the expression of the constraint condition is: wherein represents the demanded torque during the starting process of the main engine of the aircraft; represents the electromagnetic torque of the main electric machine; represents the electromagnetic torque of the main exciter machine; represents the electrical angular speed of the main electric machine; represents the electrical angular speed of the main electric machine represents the axial stator flux of the main electric machine; represents the electrical angular speed of the main electric machine represents the axial stator flux of the main electric machine; represents the electrical angular speed of the main exciter machine represents the axial stator flux of the main exciter machine; represents the electrical angular speed of the main exciter machine represents the axial stator flux of the main exciter machine; represents the amplitude of the maximum voltage vector that the main electric machine inverter can provide; represents the amplitude of the maximum voltage vector that the main exciter machine inverter can provide; represents the amplitude of the maximum current vector that the main electric machine inverter can provide; represents the amplitude of the maximum current vector that the main exciter machine inverter can provide; corresponds to the amplitudes of the maximum voltage and current vectors that the main electric and exciter machine inverters can provide; represents the electrical angular speed of the main electric machine represents the axial stator current of the main electric machine; represents the electrical angular speed of the main electric machine represents the axial stator current of the main electric machine; represents the electrical angular speed of the main exciter machine represents the axial stator current of the main exciter machine; represents the electrical angular speed of the main exciter machine represents the axial stator current of the main exciter machine.

8. A controllable loss minimization control method of a multi-stage starting generator under controllable excitation conditions according to claim 1, characterized in that, Under the constraints of the output capability of the main exciter inverter and the main motor inverter and the starting demand torque of the aeroengine, the target stator current of the main motor is solved to minimize the controllable loss of the multi-stage starting generator The steps of the shaft magnetizing current and the target excitation voltage of the main exciter are: By establishing the Lagrange function and according to the KKT condition, the minimum controllable loss working point of the multi-stage motor is the solution of the following equation: The calculation iteration initial value is obtained by first-order Taylor expansion: wherein represents an iteration function for calculating the minimum controllable loss operating point; represents the sixth order coefficient of the iteration function; represents the fifth order coefficient of the iteration function; represents the fourth order coefficient of the iteration function; represents the third order coefficient of the iteration function; represents the second order coefficient of the iteration function; represents the first order coefficient of the iteration function; represents the constant term of the iteration function; represents the independent variable of the iteration function; represents the iteration initial value for calculating the minimum controllable loss operating point; represents the electrical angular velocity of the main motor; represents the stator axial inductance; represents the stator axial inductance; represents the stator winding resistance; represents the equivalent iron loss resistance; the relationship between the k+1th operating point and the kth operating point in the iteration process is , according to which the corresponding of the multi-stage starting generator at the minimum controllable loss can be obtained, and further the target field voltage of the corresponding main field motor and the target stator axial magnetization current of the main motor are obtained.

9. A controllable loss minimization control system for a multi-stage starting generator under controllable field conditions, characterized by, Comprise: The controllable loss obtaining module of the main motor is configured to, in a rotating coordinate system of the main motor, take the sum of the stator iron loss and the rotor iron loss of the main motor as a heat loss of an equivalent iron loss resistance of the main motor, and obtain a direct-axis equivalent circuit and a quadrature-axis equivalent circuit of the main motor considering the controllable loss; based on the direct-axis equivalent circuit and the quadrature-axis equivalent circuit of the main motor considering the controllable loss, the controllable loss of the main motor is obtained by converting the controllable loss of the main motor into a function about the stator magnetization current and the excitation current of the main motor based on the relationship among the stator current, the stator magnetization current and the iron loss current of the main motor; The controllable loss obtaining module of the main excitation motor is configured to, in a rotating coordinate system of the main excitation motor, take the sum of the stator iron loss and the rotor iron loss of the main excitation motor as a heat loss of an equivalent iron loss resistance of the main excitation motor, and obtain a direct-axis equivalent circuit and a quadrature-axis equivalent circuit of the main excitation motor considering the controllable loss; according to a three-phase full-wave uncontrolled rectification formula, a working characteristic formula of the rotary rectifier is obtained, and according to the direct-axis equivalent circuit and the quadrature-axis equivalent circuit of the main excitation motor and the working characteristic formula of the rotary rectifier, the relationship among the stator current, the stator magnetization current, the iron loss current of the main excitation motor and the excitation current of the main motor is obtained; The controllable loss of the main excitation motor is obtained by converting the controllable loss of the main excitation motor into a function about the excitation current of the main motor based on the relationship among the stator current, the stator magnetization current, the iron loss current of the main excitation motor and the excitation current of the main motor; The controllable loss obtaining module of the rotary rectifier is configured to obtain the controllable loss of the rotary rectifier according to the excitation current of the main motor and the conduction voltage drop and the equivalent conduction resistance of the diode in the rotary rectifier; The controllable loss obtaining module of the multi-stage starting generator is configured to obtain the controllable loss of the multi-stage starting generator according to the controllable loss of the main motor, the controllable loss of the main excitation motor and the controllable loss of the rotary rectifier; The minimum controllable loss solving module is configured to obtain the controllable loss of the multi-stage starting generator according to the controllable loss of the main motor, the controllable loss of the main exciter and the controllable loss of the rotary rectifier; and to solve the target stator voltage of the main motor under the constraint conditions of the output capability of the main exciter inverter and the main motor inverter and the starting demand torque of the aeroengine, so that the controllable loss of the multi-stage starting generator is minimum The shaft magnetization current and the target excitation voltage of the main exciter. A control module is configured to determine a target stator magnetizing current and a target field voltage based on the target stator magnetizing current and a target field voltage based on the target stator 10. A storage medium, characterized by The computer program is executed by the processor to implement the steps of the method in any one of claims 1-8.

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