Adaptive impedance reshaping oscillation suppression method for airborne electrically excited power generation system

Abstract

This invention discloses an adaptive impedance reshaping oscillation suppression method for aviation electrically excited power generation systems, belonging to the field of aviation power generation system control technology. It can solve the instability and oscillation problem of power generation systems operating with constant power loads and adapt to complex operating condition changes, improving system stability and stability margin. This invention introduces a virtual admittance element into the voltage regulation control of the power generation system, equivalent to adding an admittance in parallel with the inherent impedance of the power generation system. This reshapes the output impedance of the power generation system to avoid cross-intercept oscillations with the input impedance of the constant power load, optimizing the impedance matching between the power generation system and the constant power load. Furthermore, this method can adaptively correct the virtual admittance based on the system's operating state to ensure stable operation of the power generation system under different conditions, thus effectively improving the stability and reliability of aviation electrically excited power generation systems. This invention is applicable to oscillation suppression in aviation power generation systems.

Description

Technical Field

[0001] This invention relates to the field of aviation power generation system control technology, and in particular to an adaptive impedance reshaping oscillation suppression method for aviation electrically excited power generation systems. Background Technology

[0002] The development of more electric, all-electric, and electric propulsion aircraft has led to a dramatic increase in the number and types of electrical loads in aviation electrical systems. In particular, constant power loads, mainly composed of power electronic converters and motors, are gradually replacing traditional linear loads on aircraft as the main type of airborne electrical equipment. Constant power loads exhibit strong nonlinearity during operation, and their port impedances show a "negative resistance" characteristic. This makes it difficult to match the impedance of the power generation system, causing the system to deviate from its normal operating point and generate unstable oscillations. This affects the power quality and stability of the power supply from the power generation system, which is detrimental to the safe and stable operation of the airborne electrical system.

[0003] Currently, oscillation suppression methods for aviation power generation systems are mainly divided into two types: source-side compensation and load-side compensation. Source-side compensation generally improves stability margin by increasing the output filter capacitor or parallel resistor damping element of the power generation system. This method requires the addition of extra devices to the system, reducing the system's power density. Load-side compensation introduces oscillation compensation algorithms into the load control strategy, improving the load's stability margin to avoid affecting the stability of the power generation system. Since airborne power systems have a large number of loads, this method not only requires dedicated design for each constant power load but also needs to consider the impact of multiple loads connected to the system, increasing design complexity and hindering system scalability.

[0004] Therefore, for aviation power systems, addressing the stability issues caused by constant power loads at the system's source and reshaping the impedance of the power generation system to make it more compatible with the load are key technologies that need to be mastered. Researching oscillation suppression methods for aviation power generation systems is of great significance. Among these, how to solve the instability and oscillation problems of the power generation system under constant power loads and adapt to complex operating conditions, thereby improving the system's stability and stability margin, has become a topic requiring specific research. Summary of the Invention

[0005] The embodiments of the present invention provide an adaptive impedance reshaping oscillation suppression method for an aviation electrically excited power generation system, which can solve the instability and oscillation problem of the power generation system when operating with a constant power load and adapt to complex operating condition changes, thereby improving the stability and stability margin of the system.

[0006] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0007] An adaptive impedance reshaping oscillation suppression method for an aircraft electrically excited power generation system includes:

[0008] Step 1: Acquire the output voltage u of the aviation electrically excited generator system dc And extract u through the filtering module dc The oscillation component Δu in dc ;

[0009] Step 2: Convert the oscillation component Δu dc Input the virtual admittance adaptive impedance reshaping module to calculate the output current compensation value Δi required by the power generation system to suppress oscillating components. dc ;

[0010] Step 3: Set Δi dc Input the model to the solver module and convert it into the excitation current compensation value Δi required to suppress the oscillation component. ex ;

[0011] Step 4: Adjust the excitation current compensation value Δi ex The reference value of the output excitation current of the voltage loop regulator i exb Adding them together, we obtain the excitation current reference value i containing the oscillation suppression component. exref ;

[0012] Step 5: The output of the current loop regulator generates a duty cycle signal d through a PWM stage. The duty cycle signal d is used to control the MOSFET in the excitation power circuit of the power generation system controller, thereby regulating the output voltage of the power generation system. Both the voltage loop regulator and the current loop regulator can be in the form of a PI controller.

[0013] Specifically, the aviation electrically excited power generation system includes: an electrically excited brushless synchronous generator, a three-phase bridge diode rectifier circuit, an output capacitor, and a power generation voltage regulation unit. The electrically excited brushless synchronous generator consists of a permanent magnet auxiliary exciter, a main exciter, a rotating rectifier, and a main generator. The power generation voltage regulation unit consists of a sampling and signal conditioning module, a microprocessor module, and an excitation power module. The program for the adaptive impedance reshaping oscillation suppression method is loaded into the microprocessor module.

[0014] In step one, the filtering module is a bandpass filter with a transfer function G. BPF (s) is represented as: Where ω0 is the center frequency, Q is the quality factor, and s is the differential operator. u is extracted through the filtering module. dc The oscillation component Δu in dc The method is as follows: .

[0015] Step two includes: setting Δu dcThe virtual admittance adaptive impedance reshaping module is used to obtain the output current compensation value Δi of the power generation system. dc Among them, the virtual admittance adaptive impedance reshaping module Y adap (s) consists of a virtual admittance part Y(s) and an admittance adaptive adjustment part δ(s); the transfer function of the admittance adaptive adjustment part δ(s) is: T is the sampling period; γ represents the voltage correction coefficient. R and C represent virtual resistance and virtual capacitance, respectively; .

[0016] In the preferred embodiment, the value of γ is equal to the target ripple of the output voltage, u. ~ref 1 / 6; 1mΩ≤R≤10mΩ, C dc ≤C≤2C dc C dc This represents the filter capacitor.

[0017] The model solution module includes the main generator characteristic calculation unit C(s) and the main exciter characteristic coefficient K. if C (s) is used to calculate the excitation compensation value Δi of the main generator. mex Compensation value Δi for the output current of the power generation system dc The ratio is expressed as: L md The armature inductance of the main generator, ω e The electric angular velocity of the main generator, P L Let be the load power of the electrically excited synchronous generator, and s be the differential operator;

[0018] Δi dc Input the model solver module and output the excitation current compensation value Δi. ex , is represented as: K if Equal to the excitation current compensation value Δi ex With the excitation compensation value Δi of the main generator mex The ratio is related to the design of the electrically excited brushless synchronous generator itself, and its range is generally 3.0 ≤ K. if ≤4.5.

[0019] The adaptive impedance reshaping oscillation suppression method for aviation electrically excited power generation systems provided in this invention introduces a virtual admittance element into the voltage regulation control of the power generation system. This is equivalent to adding an admittance in parallel with the inherent impedance of the power generation system, thereby reshaping the output impedance of the power generation system to avoid cross-intersection oscillations with the input impedance of the constant power load. This optimizes the impedance matching between the power generation system and the constant power load. At the same time, this method can adaptively correct the virtual admittance based on the system's operating state to meet the stable operation of the power generation system under different operating conditions. Therefore, this method can effectively improve the stability and reliability of aviation electrically excited power generation systems. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments 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.

[0021] Figure 1 A schematic diagram of the structure of an aviation electrically excited DC power generation system provided in an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the power generation voltage regulation unit architecture provided in an embodiment of the present invention.

[0023] Figure 3 A block diagram of the adaptive impedance reshaping oscillation suppression method provided in an embodiment of the present invention.

[0024] Figure 4 The voltage simulation waveform of the power generation system under variable load conditions is provided in the embodiment of the present invention.

[0025] Figure 5 The system voltage simulation waveform diagram when the impedance reshaping oscillation suppression method provided in the embodiment of the present invention is enabled.

[0026] Figure 6 The voltage simulation waveform diagram of the power generation system under variable load conditions using the adaptive impedance reshaping oscillation suppression method is provided in the embodiment of the present invention. Detailed Implementation

[0027] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Embodiments of the present invention will be described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in the specification of the present invention means the presence of features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say that an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0028] This invention provides an adaptive impedance reshaping oscillation suppression method for an airborne electrically excited power generation system. The oscillation suppression method is used in an airborne electrically excited power generation system, which consists of an electrically excited brushless synchronous generator, a three-phase bridge diode rectifier circuit, an output capacitor, and a power generation voltage regulation unit, such as... Figure 1 As shown.

[0029] The electrically excited brushless synchronous generator consists of a permanent magnet auxiliary exciter, a main exciter, a rotating rectifier, and a main generator. The permanent magnet auxiliary exciter is a permanent magnet synchronous generator, the main exciter is a rotating armature type electrically excited synchronous generator, the rotating rectifier is a three-phase bridge diode rectifier circuit, and the main generator is a rotating magnetic pole type electrically excited synchronous generator. The three generators and the rotating rectifier are coaxially mounted and connected sequentially.

[0030] The generator voltage regulation unit consists of a sampling and signal conditioning module, a microprocessor module, and an excitation power module. For example... Figure 2As shown in the figure. The sampling and signal conditioning module includes voltage and current sensors, speed sensors, and signal conditioning circuits; the microprocessor module is a digital computing circuit based on a DSP chip; and the excitation power module includes a rectifier circuit and an asymmetrical half-bridge circuit.

[0031] The adaptive impedance reshaping control method is loaded into the microprocessor module, such as... Figure 3 As shown, the following is a detailed explanation, including the following steps:

[0032] Step 1: Collect the output voltage u of the power generation system dc And extract u through the filtering module dc The oscillation component Δu in dc Specifically, it is a bandpass filter G BPF (s) is implemented, and its transfer function can be expressed as: Where ω0 is the center frequency, which should be set near the oscillation frequency in practical applications; Q is the quality factor, with a value of ω0 / BW, and BW is the bandwidth, which should be determined in conjunction with the oscillation frequency range under all operating conditions of the power generation system in practical applications, generally ranging from 20 to 60 Hz to ensure the wide-range adaptability of the bandpass filter. The extracted oscillation component Δu dc Its absolute value should be taken, which can be expressed as: .

[0033] Step 2: Convert the output voltage oscillation component Δu dc The virtual admittance adaptive impedance reshaping module is used to obtain the output current compensation value Δi of the power generation system. dc Virtual admittance adaptive impedance reshaping module Y adap Specifically, (s) consists of the virtual admittance Y(s) and the admittance adaptive adjustment part δ(s). The transfer function of the virtual admittance Y(s) can be expressed as: In this diagram, R and C represent the virtual resistance and capacitance, respectively. Considering the actual power of the electrically excited synchronous generator, the virtual resistance R typically ranges from 1 to 10 mΩ; the value of the virtual resistance can be increased as the actual power increases. The virtual capacitance C is generally taken from the value of the filter capacitor C0. dc 1 to 2 times the size;

[0034] The admittance adaptive correction part δ(s) is achieved by adjusting the oscillation component Δu. dc The transfer function can be expressed as follows: (The RMS value is calculated and then multiplied by the voltage correction factor γ.) Where T is the sampling period, and the magnitude of the voltage correction coefficient is taken as the output voltage target ripple u. ~ref 1 / 6 of.

[0035] Step 3: Output current compensation value Δi dc The excitation current compensation value Δi is obtained through the model solving module.ex The model solution module consists of the main generator characteristic solution unit C(s) and the main exciter characteristic coefficient K. if The main generator characteristic calculation unit C(s) is responsible for calculating the main generator excitation compensation value Δi. mex Compensation value Δi for the output current of the power generation system dc The ratio of can be expressed as: , where L md The armature inductance of the main generator, ω e The electric angular velocity of the main generator, P L The load power of the electrically excited synchronous generator; the exciter characteristic coefficient K. if The excitation current compensation value Δi ex With the excitation compensation value Δi of the main generator mex The ratio is related to the design of the electrically excited brushless synchronous generator itself, and its range is generally 3.0~4.5.

[0036] Step 4: Excitation current compensation value Δi ex The excitation current reference value i output by the voltage loop regulator exb By adding them together, we can obtain the excitation current reference value i containing the oscillation suppression component. exref As reference values ​​for the current loop regulator, both the voltage loop regulator and the current loop regulator are selected as PI regulators.

[0037] Step 5: The output of the current loop regulator generates a duty cycle signal d through the PWM stage to control the MOSFET of the excitation power circuit in the generator system controller, thereby regulating the output voltage of the electrically excited generator system and suppressing the oscillation of the system output voltage.

[0038] The following explanation will be illustrated with examples, including simulations. Figure 4-6 This is a schematic diagram of the simulation results provided by the present invention.

[0039] Figure 4 The waveform of the generator system's output voltage is presented as the constant power load power in the system is gradually increased. It can be seen that when the constant power load reaches a certain level, the system's output voltage begins to oscillate. Impedance reshaping control methods are enabled under system oscillation conditions, such as... Figure 5 As shown, the system transitions from oscillation to stable operation, meaning the large fluctuations in output voltage disappear. Simultaneously, the control method can adapt to varying load conditions, such as... Figure 6 As shown, adaptive and stable operation can be achieved under various load conditions, verifying the effectiveness of the invented active damper.

[0040] In practical applications, this embodiment first acquires the output voltage of the power generation system and extracts its oscillation component through a filtering module. Then, both are input into a virtual admittance module to obtain the output current compensation value of the power generation system. This value is then converted into an excitation current compensation value through a model solving module. Subsequently, this value is added to the output of the voltage loop to update the excitation current command, ultimately achieving oscillation suppression of the electrically excited power generation system. This invention solves the problem of unstable oscillation in the power generation system caused by constant power loads in aviation power systems. By introducing virtual admittance into the voltage regulation control to reshape the output impedance of the power generation system, and by adaptively correcting the virtual admittance based on the system's operating status, it meets the stable operation requirements of the power generation system under different operating conditions, improving the stability and reliability of the aviation electrically excited power generation system.

[0041] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The above descriptions are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An adaptive impedance reshaping oscillation suppression method for an aircraft electrically excited power generation system, characterized in that, include: Step 1: Acquire the output voltage u of the aviation electrically excited generator system dc And extract u through the filtering module dc The oscillating component Δu in dc ; Step 2: Convert the oscillation component Δu dc Input the virtual admittance adaptive impedance reshaping module to calculate the output current compensation value Δi required by the power generation system to suppress oscillating components. dc ; Step 3: Set Δi dc Input the model to the solver module and convert it into the excitation current compensation value Δi required to suppress the oscillation component. ex ; Step 4: Adjust the excitation current compensation value Δi ex The reference value of the output excitation current of the voltage loop regulator i exb Adding them together, we obtain the excitation current reference value i containing the oscillation suppression component. exref ; Step 5: The output of the current loop regulator generates a duty cycle signal d through the PWM stage. Here, d is used to control the MOSFET of the excitation power circuit in the generator system controller, thereby regulating the output voltage of the generator system. In step two, the virtual admittance adaptive impedance reshaping module Y... adap (s) consists of a virtual admittance component Y(s) and an admittance adaptive adjustment component δ(s); The transfer function of the admittance adaptive adjustment component δ(s) is: T is the sampling period; γ represents the voltage correction coefficient; R and C represent virtual resistance and virtual capacitance, respectively; .

2. The method according to claim 1, characterized in that, The aviation electrically excited power generation system includes: an electrically excited brushless synchronous generator, a three-phase bridge diode rectifier circuit, an output capacitor, and a power generation voltage regulation unit; The electrically excited brushless synchronous generator consists of a permanent magnet auxiliary exciter, a main exciter, a rotating rectifier, and a main generator. The power generation voltage regulation unit consists of a sampling and signal conditioning module, a microprocessor module, and an excitation power module.

3. The method according to claim 1, characterized in that, In step one, the filtering module is a bandpass filter, wherein the transfer function G BPF (s) is represented as: , where ω0 is the center frequency, Q is the quality factor, and s is the differential operator.

4. The method according to claim 3, characterized in that, u is extracted through the filtering module. dc The oscillating component Δu in dc The method is as follows: .

5. The method according to claim 1, characterized in that, γ equals the target ripple of the output voltage u ~ref 1 / 6; 1mΩ≤R≤10mΩ, C dc ≤C≤2C dc C dc This represents the filter capacitor.

6. The method according to claim 1, characterized in that, The model solving module includes the main generator characteristic calculation unit C(s) and the main exciter characteristic coefficient K. if C(s) is used to calculate the excitation compensation value Δi of the main generator. mex Compensation value Δi for the output current of the power generation system dc The ratio is expressed as: L md The armature inductance of the main generator, ω e The electric angular velocity of the main generator, P L The load power of the electrically excited synchronous generator is denoted by s, where s is the differential operator; the excitation current compensation value is... .

7. The method according to claim 6, characterized in that, 3.0≤K if ≤4.5。

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