A method for power extraction from an aviation two-shaft engine based on a two-winding generator

Abstract

This invention discloses a power extraction method for a dual-shaft aircraft engine based on a dual-winding generator, relating to the field of aviation power generation. The method includes: First, based on the characteristics of a dual-winding generator, the output reference power of the control-side windings of two dual-winding generators is calculated according to the power demands of various electrical loads. Then, the voltage loop of each dual-winding generator is compensated based on the generator's droop characteristics to control the generator's output power. This power is then transmitted step-by-step through the voltage and current loops, and finally output to the high-voltage and low-voltage shaft dual-winding generators via SVPWM modulation, thereby achieving proportional distribution of high and low voltage shaft power extraction from the aircraft dual-shaft engine. This method can reduce the impact of power extraction on engine stability margin and efficiency while ensuring multiple electrical energy outputs. Power transmission and distribution are achieved through a high-voltage DC bus connected in parallel to the generator control winding side.

Description

Technical Field

[0001] This invention relates to the field of aviation power generation, and in particular to a method for extracting power from a dual-shaft aircraft engine based on a dual-winding generator. Background Technology

[0002] Since the beginning of the 21st century, the increasing level of social electrification and the concept of more-electric aircraft have accelerated the process of aircraft electrification management. People are constantly trying to use electricity to replace secondary energy sources in aircraft, including hydraulic and pneumatic energy, to simplify the secondary energy system, reduce system weight, and decrease overall complexity. To provide the necessary electrical power to the increasing electrical loads on aircraft, power extraction technology for aero engines, especially for the most widely used twin-shaft engines in the aviation field, has become particularly important.

[0003] Traditional aircraft engine power extraction typically uses a three-stage brushless generator. This type of generator has high power generation efficiency and the related technology is relatively mature. However, it has the problem of complex structure and can only provide a single form of electrical energy. This means that a large number of power converters need to be installed on the aircraft to distribute the extracted power to all kinds of electrical loads on the aircraft, which increases both the cost and the overall weight of the system.

[0004] If a dual-winding induction generator is used as the target for power extraction, the dual-winding induction generator itself has a relatively simple structure and has two sets of windings that can naturally provide two forms of electrical energy, which is beneficial to simplifying the complexity of the aviation electrical system and reducing the overall weight of the system. However, it still cannot avoid the problem of reduced engine stability margin due to power extraction, which can easily lead to adverse phenomena such as surge.

[0005] In summary, while existing power extraction technologies each have their advantages, they also have certain limitations. Therefore, it is necessary to develop a new method for extracting high and low pressure shaft power suitable for aero-engines with dual shafts. Summary of the Invention

[0006] To address the aforementioned problems and technical requirements, the inventors have proposed a power extraction method for aero-engines based on a dual-winding generator. This invention comprehensively considers the impact of power extraction on aero-engines, and addresses the limitations of traditional power extraction methods in meeting the demands of various forms of electrical energy and their adverse effects on the engine. It employs a high- and low-voltage shaft power extraction method based on a dual-winding generator. The technical solution of this invention is as follows:

[0007] A method for power extraction from a dual-shaft aircraft engine based on a dual-winding generator includes the following steps:

[0008] One dual-winding generator has its power-side winding connected to the AC bus of the aero-engine, denoted as a high-voltage shaft dual-winding generator. The power-side winding of another dual-winding generator is connected to the low-voltage DC bus of the aero-engine, denoted as a low-voltage shaft dual-winding generator. The control-side windings of both dual-winding generators are connected in parallel to the high-voltage DC bus. The method for extracting power from the high and low voltage shafts of the aero-engine using these two dual-winding generators includes:

[0009] The output reference power of the control side windings of the two dual-winding generators is calculated based on the power requirements of various electrical loads.

[0010] The output reference power is combined with the droop characteristics of the dual-winding generator to compensate the voltage loop of each dual-winding generator. Then, through the step-by-step transmission of the voltage loop and current loop, the AC and DC axis voltage reference values ​​of the control side winding of the high-voltage shaft dual-winding generator and the AC and DC axis voltage reference values ​​of the control side winding of the low-voltage shaft dual-winding generator are obtained respectively.

[0011] The AC and DC axis voltage setpoints of the control side windings of the high-voltage shaft and low-voltage shaft dual-winding generator are output to the high-voltage shaft and low-voltage shaft dual-winding generator through SVPWM modulation, so as to realize the proportional distribution of high and low voltage shaft power extraction from the aircraft dual-shaft engine.

[0012] A further technical solution involves calculating the output reference power of the control-side windings of the two dual-winding generators based on the power requirements of various electrical loads, including:

[0013] Considering the impact of power extraction on aero-engines with two shafts, the output reference power of the control windings of the two dual-winding generators satisfies:

[0014]

[0015] In the formula, P Lref and P Href These represent the output reference power of the control side windings of the low-voltage shaft and high-voltage shaft dual-winding generators, respectively; P represents the total power required to be output by the two dual-winding generators; k represents the proportional coefficient for power extraction from the high and low voltage shafts; P Lp and P Hp These represent the power output required by the power-side windings of the low-voltage shaft and high-voltage shaft dual-winding generators, respectively.

[0016] A further technical solution is to satisfy the following formula when considering the impact of power extraction on aero-engines:

[0017]

[0018] In the formula, P kl and P kh These represent the compressor power of the low-pressure shaft and the high-pressure shaft, respectively; Ptl and P th These represent the turbine power of the low-pressure shaft and the high-pressure shaft, respectively; P L and P H These represent the power extracted from the low-pressure shaft and the high-pressure shaft, respectively; η L and η H These represent the mechanical efficiencies of the low-pressure shaft and the high-pressure shaft, respectively.

[0019] Where, P = P L +P H P L =P Lref +P Lp P H =P Href +P Hp .

[0020] A further technical solution involves compensating the voltage loop of each dual-winding generator by combining the output reference power with the droop characteristics of the dual-winding generator, including:

[0021] The output reference power of the control side winding of the low-voltage shaft and high-voltage shaft dual-winding generator is combined with the droop characteristics of the corresponding shaft dual-winding generator and the high-voltage DC bus voltage to obtain the voltage compensation value of the low-voltage shaft and high-voltage shaft dual-winding generator.

[0022] The voltage compensation values ​​of the low-voltage shaft and high-voltage shaft dual-winding generators are respectively compensated to the power loops on the control side of the low-voltage shaft and high-voltage shaft dual-winding generators. These values ​​are then added to the values ​​obtained after the difference between the output reference power and the actual power is processed by a PI regulator to obtain the output reference voltage values ​​on the control side of the low-voltage shaft and high-voltage shaft dual-winding generators, respectively.

[0023] A further technical solution involves combining the output reference power of the control side windings of the low-voltage shaft and high-voltage shaft dual-winding generators with the droop characteristics of the corresponding shaft dual-winding generators and the high-voltage DC bus voltage to obtain the voltage compensation values ​​for the low-voltage shaft and high-voltage shaft dual-winding generators, expressed as:

[0024]

[0025] In the formula, U Lcom and U Hcom These represent the voltage compensation values ​​for the low-voltage shaft and high-voltage shaft dual-winding generators, respectively; U dc Indicates the voltage of the high-voltage DC bus; P Lref and P Href These represent the output reference power of the control side windings of the low-voltage shaft and high-voltage shaft dual-winding generators, respectively; m L and m HThese represent the droop coefficients of the low-voltage shaft dual-winding generator and the high-voltage shaft dual-winding generator, respectively. For any dual-winding generator, the droop coefficient is calculated as follows:

[0026]

[0027] In the formula, a% is the voltage regulation rate of the control side of the dual-winding generator when the output power changes by ΔP.

[0028] The further technical solution is that, after compensation, the voltage loop control strategy of the high- and low-voltage shaft dual-winding generator is as follows:

[0029] The difference between the output reference voltage and the actual output voltage on the power side is calculated, and the d-axis reference current value of the dual-winding generator is obtained after passing through a PI regulator.

[0030] The difference between the output reference voltage and the actual output voltage on the control side is calculated, and after passing through the PI regulator, the q-axis reference current value of the dual-winding generator is obtained.

[0031] A further technical solution is that, after the voltage loop, the current loop control strategy of the high- and low-voltage shaft dual-winding generator is as follows:

[0032] The difference between the reference current and the actual current on the d-axis and q-axis is calculated respectively. After passing through the PI regulator, the AC and DC axis voltage setpoints of the control side windings of the high-voltage shaft dual-winding generator and the AC and DC axis voltage setpoints of the control side windings of the low-voltage shaft dual-winding generator are obtained respectively.

[0033] A further technical solution is that the method of outputting the AC and DC axis voltage setpoints of the control side windings of the high-voltage shaft and low-voltage shaft dual-winding generator to the high-voltage shaft and low-voltage shaft dual-winding generator via SVPWM modulation is the same. For any dual-winding generator, this method includes:

[0034] By combining the rotor position information of the dual-winding generator, the inverse Park transformation is performed on the AC and DC axis voltage setpoints to determine the three-phase voltage setpoints of the dual-winding generator in the three-phase stationary coordinate system. Then, the control signals of the corresponding power switches of the three-phase bridge arms are obtained through SVPWM modulation.

[0035] The beneficial technical effects of this invention are:

[0036] This method, based on the characteristics of a dual-winding generator, first calculates the output reference power of the generator's control winding according to the power demands of various electrical loads in the system. Then, it compensates for the generator's voltage loop by incorporating the generator's droop characteristics to control the generator's output power. Finally, it utilizes a high-voltage DC bus connected in parallel to the high- and low-voltage shaft dual-winding generator control windings to achieve power transfer and distribution. This method can reduce the impact of power extraction on engine stability margin and efficiency while ensuring diverse electrical energy outputs. Attached Figure Description

[0037] Figure 1 This is a block diagram of the power extraction method for aero-engines based on a dual-winding generator provided in this application.

[0038] Figure 2 This is the control block diagram of the voltage compensation circuit provided in this application.

[0039] Figure 3 This is the power-voltage curve of the dual-winding generator provided in this application. Detailed Implementation

[0040] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0041] Please refer to Figure 1 As shown, one embodiment of this application provides a method for power extraction from a dual-shaft aircraft engine based on a dual-winding generator. This method utilizes two dual-winding generators as power extraction devices for the high-voltage and low-voltage shafts of the aircraft engine. The two dual-winding generators are connected as follows: the power-side winding of one generator is connected to the AC bus of the aircraft engine (denoted as the high-voltage shaft dual-winding generator), and the power-side winding of the other generator is connected to the low-voltage DC bus of the aircraft engine (denoted as the low-voltage shaft dual-winding generator). The control-side windings of the two generators are connected in parallel to the high-voltage DC bus. While outputting multiple forms of electrical energy, the power extraction ratio of the high-voltage and low-voltage shafts is controlled by a power controller. The method for power extraction from the high and low-voltage shafts of the aircraft engine using the two dual-winding generators is integrated into the power controller. The method specifically includes the following steps:

[0042] Step 1: Calculate the output reference power of the control side windings of the two dual-winding generators based on the power requirements of various electrical loads. First, considering the impact of power extraction on the aircraft twin-shaft engine, the following formula should be satisfied:

[0043]

[0044] In the formula, P kl and P kh These represent the compressor power of the low-pressure shaft and the high-pressure shaft, respectively; P tl and Pth These represent the turbine power of the low-pressure shaft and the high-pressure shaft, respectively; P L and P H These represent the power extracted from the low-pressure shaft and the high-pressure shaft, respectively; η L and η H These represent the mechanical efficiencies of the low-pressure shaft and the high-pressure shaft, respectively.

[0045] The multi-stage turbine guide vanes used in aircraft twin-shaft engines generally operate under critical or supercritical conditions, at which point the turbine power ratio P of the high-pressure and low-pressure shafts is... tl / P th Approximately constant, when extracting power, it is necessary to ensure that the power extracted from the high and low pressure shafts maintains a certain proportion in order to reduce the impact of the extracted power on the power of the high and low pressure shaft compressors. Therefore, the output reference power of the control side windings of the two dual-winding generators satisfies:

[0046]

[0047] In the formula, P Lref and P Href These represent the output reference power of the control side windings of the low-voltage shaft and high-voltage shaft dual-winding generator, respectively; k represents the proportionality coefficient of the power extracted from the high and low voltage shafts, which is adjusted by the power controller to ensure that the extracted power is proportional; P Lp and P Hp Let P and P' represent the power output required by the power-side windings of the low-voltage shaft and high-voltage shaft dual-winding generators, respectively; P represents the total power output required by the two dual-winding generators, and P = P'''''''''''''''''''''''''''''''''''" '"' ... L +P H P L =P Lref +P Lp P H =P Href +P Hp .

[0048] Step 2: Compensate the voltage loop of each dual-winding generator by combining the output reference power with the droop characteristics of the dual-winding generator. The control block diagram is as follows: Figure 2 As shown, the output reference power P of the control side winding of the low-voltage shaft and high-voltage shaft dual-winding generator is... Lref and P Href Combining the droop characteristics of the corresponding shaft dual-winding generator and the high-voltage DC bus voltage U dc The voltage compensation values ​​for the dual-winding generator with low-voltage shaft and high-voltage shaft are obtained and expressed as follows:

[0049]

[0050] In the formula, U Lcom and U HcomThese represent the voltage compensation values ​​for the low-voltage shaft and high-voltage shaft dual-winding generators, respectively; m L and m H These represent the droop coefficients of the low-voltage shaft dual-winding generator and the high-voltage shaft dual-winding generator, respectively. For any dual-winding generator, the droop coefficient is calculated as follows:

[0051]

[0052] In the formula, a% is the voltage regulation rate of the control side of the dual-winding generator when the output power changes by ΔP.

[0053] The voltage compensation value U of the low-voltage shaft and high-voltage shaft dual-winding generator Lcom and U Hcom The difference between the output reference power and the actual power (i.e., P) is compensated separately on the control-side power loops of the low-voltage shaft and high-voltage shaft dual-winding generators. Lref With P Lc The difference, P Href With P Hc The difference between the two voltages (the power and voltage) is summed after passing through the PI regulator. This is equivalent to vertically shifting the generator's power-voltage curve. Figure 3 As shown, at the DC bus voltage U dc Under unchanged conditions, when a specific power output from the generator is required, voltage compensation shifts the curve upward by m·P2, changing the generator's operating point from 1 to 2. Alternatively, when a specific power absorption by the generator is required, voltage compensation shifts the curve downward by m·P3, changing the generator's operating point from 1 to 3. The compensated voltage serves as the output reference voltage value U on the control side of the low-voltage shaft and high-voltage shaft dual-winding generator. Lref and U Href .

[0054] Step 3: Output reference voltage value U Lref and U Href Then, through the step-by-step transmission of voltage and current loops, the AC and DC axis voltage setpoints u of the control side windings of the high-voltage shaft dual-winding generator are obtained respectively. dH * and u qH * The AC and DC axis voltage setpoint u of the control side winding of the low-voltage shaft dual-winding generator dL * and u qL * .

[0055] Specifically, calculate the difference between the output reference voltage and the actual output voltage on the power side of the two dual-winding generators (i.e., U). Hpref and U Hp The difference, U Lpref and U LpThe difference between the two currents (i and d) is used to obtain the d-axis reference current values ​​i for the two dual-winding generators after passing through a PI regulator. dH * and i dL * Simultaneously calculate the difference between the output reference voltage and the actual output voltage on the control side of both dual-winding generators (i.e., U). Href and U dc The difference, U Lref and U dc The difference between the two currents (i and q) is used to obtain the q-axis reference current value i of the two dual-winding generators after passing through a PI regulator. qH * and i qL * Then calculate the difference between the reference current and the actual current on the d-axis and q-axis respectively (i.e., i... dH * and i dH The difference, i qH * and i qH The difference, i qL * and i qL The difference, i dL * and i dL The difference between the two values ​​(i and ii) is used to obtain the AC and DC axis voltage setpoints u of the control side windings of the high-voltage shaft dual-winding generator after passing through a PI regulator. dH * and u qH * And the AC and DC axis voltage setpoint u of the control side winding of the low-voltage shaft dual-winding generator. dL * and u qL * .

[0056] Step 4: The AC and DC axis voltage setpoints of the control windings of the high-voltage and low-voltage shaft dual-winding generators are output to the high-voltage and low-voltage shaft dual-winding generators via SVPWM modulation to achieve proportional distribution of high and low voltage shaft power extraction from the aircraft dual-shaft engine. Specifically, for any dual-winding generator, the AC and DC axis voltage setpoints are subjected to inverse Park transformation based on its rotor position information to determine the three-phase voltage setpoints of the dual-winding generator in the three-phase stationary coordinate system. Then, the control signals for the corresponding power switches of the three-phase bridge arms are obtained through SVPWM modulation.

[0057] The above descriptions are merely preferred embodiments of this application, and the present invention is not limited to the above embodiments. It is understood that other improvements and variations directly derived or conceived by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.

Claims

1. A method for power extraction from a dual-shaft aircraft engine based on a dual-winding generator, characterized in that, One dual-winding generator has its power-side winding connected to the AC bus of the aero-engine, denoted as a high-voltage shaft dual-winding generator. The power-side winding of another dual-winding generator is connected to the low-voltage DC bus of the aero-engine, denoted as a low-voltage shaft dual-winding generator. The control-side windings of both dual-winding generators are connected in parallel to the high-voltage DC bus. The method for extracting power from the high and low voltage shafts of the aero-engine using these two dual-winding generators includes: The output reference power of the control side windings of the two dual-winding generators is calculated based on the power requirements of various electrical loads. The output reference power is combined with the droop characteristics of the dual-winding generator to compensate the voltage loop of each dual-winding generator. Then, through the step-by-step transmission of the voltage loop and the current loop, the AC and DC axis voltage reference values ​​of the control side winding of the high-voltage shaft dual-winding generator and the AC and DC axis voltage reference values ​​of the control side winding of the low-voltage shaft dual-winding generator are obtained respectively. The AC and DC axis voltage setpoints of the control side windings of the high-voltage shaft and low-voltage shaft dual-winding generator are output to the high-voltage shaft and low-voltage shaft dual-winding generator through SVPWM modulation, so as to realize the proportional distribution of high and low voltage shaft power extraction from the aircraft dual-shaft engine.

2. The method for power extraction from a dual-shaft aircraft engine based on a dual-winding generator according to claim 1, characterized in that, The calculation of the output reference power of the control side windings of the two dual-winding generators based on the power requirements of various electrical loads includes: Considering the impact of power extraction on aero-engines with two shafts, the output reference power of the control windings of the two dual-winding generators satisfies: In the formula, P Lref and P Href These represent the output reference power of the control side windings of the low-voltage shaft and high-voltage shaft dual-winding generators, respectively; P represents the total power required to be output by the two dual-winding generators; k represents the proportional coefficient for power extraction from the high and low voltage shafts; P Lp and P Hp These represent the power output required by the power-side windings of the low-voltage shaft and high-voltage shaft dual-winding generators, respectively.

3. The method for power extraction from a dual-shaft aircraft engine based on a dual-winding generator according to claim 2, characterized in that, When considering the impact of power extraction on aero-twin engines, the following formula is satisfied: In the formula, P kl and P kh These represent the compressor power of the low-pressure shaft and the high-pressure shaft, respectively; P tl and P th These represent the turbine power of the low-pressure shaft and the high-pressure shaft, respectively; P L and P H These represent the power extracted from the low-pressure shaft and the high-pressure shaft, respectively. η L and η H These represent the mechanical efficiencies of the low-pressure shaft and the high-pressure shaft, respectively. Where, P = P L +P H P L =P Lref +P Lp P H =P Href +P Hp .

4. The method for extracting power from a dual-shaft aircraft engine based on a dual-winding generator according to claim 1, characterized in that, The output reference power, combined with the droop characteristics of the dual-winding generator, compensates the voltage loop of each dual-winding generator, including: The output reference power of the control side winding of the low-voltage shaft and high-voltage shaft dual-winding generator is combined with the droop characteristics of the corresponding shaft dual-winding generator and the high-voltage DC bus voltage to obtain the voltage compensation value of the low-voltage shaft and high-voltage shaft dual-winding generator. The voltage compensation values ​​of the low-voltage shaft and high-voltage shaft dual-winding generators are respectively compensated to the power loops on the control side of the low-voltage shaft and high-voltage shaft dual-winding generators. These values ​​are then added to the values ​​obtained after the difference between the output reference power and the actual power is passed through a PI regulator to obtain the output reference voltage values ​​on the control side of the low-voltage shaft and high-voltage shaft dual-winding generators, respectively.

5. The method for extracting power from a dual-shaft aircraft engine based on a dual-winding generator according to claim 4, characterized in that, The output reference power of the control side winding of the low-voltage shaft and high-voltage shaft dual-winding generator, combined with the droop characteristics of the corresponding shaft dual-winding generator and the high-voltage DC bus voltage, yields the voltage compensation value of the low-voltage shaft and high-voltage shaft dual-winding generator, expressed as: In the formula, U Lcom and U Hcom These represent the voltage compensation values ​​for the low-voltage shaft and high-voltage shaft dual-winding generators, respectively; U dc Indicates the voltage of the high-voltage DC bus; P Lref and P Href These represent the output reference power of the control side windings of the low-voltage shaft and high-voltage shaft dual-winding generators, respectively; m L and m H These represent the droop coefficients of the low-voltage shaft dual-winding generator and the high-voltage shaft dual-winding generator, respectively. For any dual-winding generator, the droop coefficient is calculated as follows: In the formula, a% is the voltage regulation rate of the control side of the dual-winding generator when the output power changes by ΔP.

6. The method for power extraction from a dual-shaft aircraft engine based on a dual-winding generator according to claim 1, characterized in that, After compensation, the voltage loop control strategy for the dual-winding generator with high and low voltage shafts is as follows: The difference between the output reference voltage and the actual output voltage on the power side is calculated, and the d-axis reference current value of the dual-winding generator is obtained after passing through a PI regulator. The difference between the output reference voltage and the actual output voltage on the control side is calculated, and after passing through the PI regulator, the q-axis reference current value of the dual-winding generator is obtained.

7. The method for power extraction from a dual-shaft aircraft engine based on a dual-winding generator according to claim 1, characterized in that, The current loop control strategy for the generator with dual high- and low-voltage shaft windings, after the voltage loop, is as follows: The difference between the reference current and the actual current on the d-axis and q-axis is calculated respectively. After passing through the PI regulator, the AC and DC axis voltage setpoints of the control side windings of the high-voltage shaft dual-winding generator and the AC and DC axis voltage setpoints of the control side windings of the low-voltage shaft dual-winding generator are obtained respectively.

8. The method for power extraction from a dual-shaft aircraft engine based on a dual-winding generator according to claim 1, characterized in that, The method for outputting the AC and DC axis voltage setpoints of the control side windings of the high-voltage shaft and low-voltage shaft dual-winding generator to the high-voltage shaft and low-voltage shaft dual-winding generator via SVPWM modulation is the same. For any dual-winding generator, the method includes: By combining the rotor position information of the dual-winding generator, the inverse Park transformation is performed on the AC and DC axis voltage setpoints to determine the three-phase voltage setpoints of the dual-winding generator in the three-phase stationary coordinate system. Then, the control signals of the corresponding power switches of the three-phase bridge arms are obtained through SVPWM modulation.

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