Aviation double-shaft engine power extraction method based on double-winding generator

Abstract

The invention discloses an aviation double-shaft engine power extraction method based on double-winding generators, and relates to the field of aviation power generation, and the method comprises the steps: firstly, calculating the output reference power of control side windings of two double-winding generators according to the power requirements of various electrical loads based on the characteristics of the double-winding generators; and compensating a voltage loop of each double-winding generator by combining the droop characteristic of the generator so as to achieve the purpose of controlling the output power of the generator, transmitting the output power step by step through the voltage loop and the current loop, and finally outputting the output power to the high-voltage-shaft and low-voltage-shaft double-winding generators through SVPWM (Space Vector Pulse Width Modulation) modulation. Therefore, the power extraction of high and low pressure shafts of the aviation double-shaft engine is proportionally distributed. According to the method, the influence of power extraction on the stability margin and efficiency of the engine can be reduced while output of various electric energy is guaranteed, and power transmission and distribution are achieved through the high-voltage direct-current buses connected in parallel on the winding side of the generator control winding.

Description

Technical Field

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

[0002] Since the 21st century, the improvement of social electrification and the concept of more electric aircraft have accelerated the process of aircraft electrification management. People have been trying to use electric energy to replace secondary energy sources such as hydraulic energy and air pressure energy in aircraft, simplifying the secondary energy system of aircraft, reducing system weight and overall redundancy. In order to provide the necessary electric energy for the increasing number of electrical loads on aircraft, the power extraction technology of aircraft engines, especially the power extraction of aviation twin-shaft engines, which are the most widely used in the aviation field, has become particularly important.

[0003] Traditional aircraft engine power extraction is usually achieved using a three-stage brushless generator, which has high power generation efficiency and relatively mature related technologies. However, it has a complex structure and can only provide a single form of electrical energy. This means that the aircraft needs to be equipped with a large number of power converters to distribute the extracted power to all types of electrical loads on the aircraft, which increases both costs and the overall weight of the system.

[0004] If a dual-winding induction generator is used as the object of power extraction, since 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, it is beneficial to simplify the complexity of the aviation electrical system and reduce the total weight of the system. However, it still cannot avoid the problem that the engine stability margin is reduced due to power extraction, which is easy to cause surge and other adverse phenomena.

[0005] In summary, although the existing power extraction technologies have their own advantages, they all have certain limitations. Therefore, it is necessary to develop a new high- and low-pressure shaft power extraction method suitable for aviation dual-shaft engines. Summary of the invention

[0006] In view of the above problems and technical requirements, the inventors have proposed a method for extracting power from an aviation dual-shaft engine based on a dual-winding generator. The invention comprehensively considers the impact of power extraction on aviation dual-shaft engines, and adopts a high- and low-pressure shaft power extraction method based on a dual-winding generator in view of the fact that traditional power extraction methods cannot meet the needs of various forms of electric energy and have adverse effects on the engine. The technical solution of the invention is as follows:

[0007] A method for extracting power from an aviation dual-shaft engine based on a dual-winding generator comprises the following steps:

[0008] The power side winding of a dual-winding generator is connected to the AC bus of the aircraft engine, which is recorded 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 aircraft engine, which is recorded as a low-voltage shaft dual-winding generator. The control side windings of the two dual-winding generators are connected in parallel to the high-voltage DC bus. The method for the two dual-winding generators to extract power from the high and low voltage shafts of the aircraft engine includes:

[0009] The output reference power of the control side windings of two double-winding generators is calculated according to 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, and then the AC and DC axis voltage set values ​​of the control side winding of the high-voltage shaft dual-winding generator and the AC and DC axis voltage set values ​​of the control side winding of the low-voltage shaft dual-winding generator are obtained through the step-by-step transmission of the voltage loop and the current loop.

[0011] The AC and DC axis voltage set values ​​of the control side windings of the high-pressure shaft and low-pressure shaft dual-winding generators are output to the high-pressure shaft and low-pressure shaft dual-winding generators through SVPWM modulation to achieve proportional distribution of the high and low pressure shaft power extraction of the aviation dual-shaft engine.

[0012] A further technical solution is to calculate the output reference power of the control side windings of the two double-winding generators according to the power requirements of various electrical loads, including:

[0013] Considering the influence of power extraction on aviation dual-shaft engines, the output reference power of the control side windings of the two dual-winding generators satisfies:

[0014]

[0015] Where P Lref and P Href represents the output reference power of the control side winding of the low-voltage shaft and high-voltage shaft double-winding generator respectively; P represents the total power that the two double-winding generators need to output; k represents the proportional coefficient of the power extracted from the high-voltage and low-voltage shafts; P Lp and P Hp They respectively represent the power that needs to be output by the power side windings of the low-voltage shaft and high-voltage shaft double-winding generators.

[0016] A further technical solution is to satisfy the following formula when considering the influence of power extraction on the aviation dual-shaft engine:

[0017]

[0018] Where P kl and P kh Represents the compressor power of the low-pressure shaft and the high-pressure shaft respectively; Ptl and P th Represents the turbine power of the low-pressure shaft and the high-pressure shaft respectively; P L and P H Represent the power extracted from the low-pressure shaft and the high-pressure shaft respectively; η L and η H Represent the mechanical efficiency 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 is to output reference power in combination with the droop characteristics of the dual-winding generator to compensate the voltage loop of each dual-winding generator, including:

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

[0022] The voltage compensation values ​​of the low-voltage shaft and high-voltage shaft dual-winding generators are respectively compensated to the control side power loops of the low-voltage shaft and high-voltage shaft dual-winding generators, and added to the value obtained after the difference between the output reference power and the actual power passes through the PI regulator to obtain the output reference voltage values ​​of the control side of the low-voltage shaft and high-voltage shaft dual-winding generators.

[0023] A further technical solution is that the output reference power of the control side winding of the low-voltage shaft and high-voltage shaft double-winding generator is combined with the droop characteristics of the double-winding generator of the corresponding shaft and the high-voltage DC bus voltage to obtain the voltage compensation value of the low-voltage shaft and high-voltage shaft double-winding generator, which is expressed as:

[0024]

[0025] Where U Lcom and U Hcom Respectively represent the voltage compensation value of the low-voltage shaft and high-voltage shaft double-winding generator; U dc Indicates the high-voltage DC bus voltage; P Lref and P Href Respectively represent the output reference power of the control side winding of the low-voltage shaft and high-voltage shaft double-winding generator; m L and m HThey represent the droop coefficient of the low-voltage shaft double-winding generator and the droop coefficient of the high-voltage shaft double-winding generator respectively; for any double-winding generator, the droop coefficient is calculated as follows:

[0026]

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

[0028] Its further technical solution is that after compensation, the voltage loop control strategy of the high-low voltage shaft double-winding generator is:

[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 the PI regulator;

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

[0031] Its further technical solution is that after passing through the voltage loop, the current loop control strategy of the high and low voltage shaft double winding generator is:

[0032] The differences between the reference current and the actual current of the d-axis and q-axis are calculated respectively, and after passing through the PI regulator, the AC and DC axis voltage set values ​​of the control side winding of the high-voltage axis double-winding generator and the AC and DC axis voltage set values ​​of the control side winding of the low-voltage axis double-winding generator are obtained respectively.

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

[0034] The inverse Park transformation of the AC-DC axis voltage given value is performed on the rotor position information of the dual-winding generator to determine the three-phase voltage given value of the dual-winding generator in the three-phase stationary coordinate system, and then the control signal of the corresponding power switch tube of the three-phase bridge arm is obtained through SVPWM modulation.

[0035] The beneficial technical effects of the present invention are:

[0036] This method is based on the characteristics of the dual-winding generator. First, the output reference power of the control side winding of the dual-winding generator is calculated according to the power requirements of various electrical loads in the system. Then, the voltage loop of the generator is compensated in combination with the droop characteristics of the generator to achieve the purpose of controlling the output power of the generator. The high-voltage DC bus connected in parallel with the control side windings of the high- and low-voltage shaft dual-winding generator is used to realize power transmission and distribution. This method can reduce the impact of power extraction on the stability margin and efficiency of the engine while ensuring multiple electrical energy outputs. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a block diagram of the method for extracting power from an aviation dual-shaft engine based on a dual-winding generator provided in this application.

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

[0039] Figure 3 It is a power-voltage curve diagram of a dual-winding generator provided in this application. DETAILED DESCRIPTION

[0040] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0041] Please refer to Figure 1 As shown, an embodiment of the present application provides a method for extracting power from an aircraft dual-shaft engine based on a dual-winding generator. The method uses two dual-winding generators as power extraction devices for the high-pressure shaft and the low-pressure shaft of the aircraft engine, wherein the two dual-winding generators are connected in the following manner: the power side winding of one dual-winding generator is connected to the AC bus of the aircraft engine, which is recorded as a high-pressure shaft dual-winding generator, and the power side winding of the other dual-winding generator is connected to the low-voltage DC bus of the aircraft engine, which is recorded as a low-pressure shaft dual-winding generator. The control side windings of the two dual-winding 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-pressure shaft and the low-pressure shaft is controlled by a power controller. The method for extracting power from the high and low-pressure shafts of the aircraft engine by the two dual-winding generators is integrated in 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, consider the impact of power extraction on the aviation dual-shaft engine, which should satisfy the following formula:

[0043]

[0044] Where P kl and P kh Represents the compressor power of the low-pressure shaft and the high-pressure shaft respectively; P tl and Pth Represents the turbine power of the low-pressure shaft and the high-pressure shaft respectively; P L and P H Represent the power extracted from the low-pressure shaft and the high-pressure shaft respectively; η L and η H Represent the mechanical efficiency of the low-pressure shaft and the high-pressure shaft respectively.

[0045] The multi-stage turbine guide vane used in aviation twin-shaft engines generally works in a critical or supercritical state, at which time the turbine power ratio of the high-pressure shaft and the low-pressure shaft is P tl / P th Approximately a constant, when extracting power, it should be ensured that the power extracted from the high and low pressure shafts maintains a certain ratio to reduce the influence of the extracted power on the high and low pressure shaft compressor power. Then the output reference power of the control side winding of the two double-winding generators satisfies:

[0046]

[0047] Where P Lref and P Href They represent the output reference power of the control side winding of the low-voltage shaft and high-voltage shaft double-winding generator respectively; k represents the proportional coefficient of the power extracted by the high-voltage and low-voltage shafts. The k value is adjusted by the power controller to achieve a certain proportion of the extracted power; P Lp and P Hp represents the power required to be output by the power side windings of the low-voltage shaft and high-voltage shaft double-winding generators respectively; P represents the total power required to be output by the two double-winding generators, and P = P L +P H , P L =P Lref +P Lp , P H =P Href +P Hp .

[0048] Step 2: Output reference power and combine the droop characteristics of the dual-winding generator to compensate the voltage loop of each 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 double-winding generator is Lref and P Href Combined with the droop characteristics of the double-winding generator of the corresponding shaft and the high-voltage DC bus voltage U dc , the voltage compensation value of the low-voltage shaft and high-voltage shaft double-winding generator is obtained, which is expressed as:

[0049]

[0050] Where U Lcom and U HcomRespectively represent the voltage compensation value of the low-voltage shaft and high-voltage shaft double-winding generator; m L and m H They represent the droop coefficient of the low-voltage shaft double-winding generator and the droop coefficient of the high-voltage shaft double-winding generator respectively. For any double-winding generator, the droop coefficient is calculated as follows:

[0051]

[0052] Where 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 double-winding generator Lcom and U Hcom The difference between the output reference power and the actual power (i.e. P Lref With P Lc The difference, P Href With P Hc The difference between the two values) is added after the PI regulator, which is equivalent to making the power-voltage curve of the generator shift vertically, such as Figure 3 As shown, the DC bus voltage U dc Under the condition that the voltage compensation is unchanged, when the generator needs to output a specific power, the curve is moved up by m·P2 through voltage compensation, so that the working point of the generator can be changed from 1 to 2, or when the generator needs to absorb a specific power, the curve is moved down by m·P3 through voltage compensation, so that the working point of the generator can be changed from 1 to 3. The compensated voltage is used as the output reference voltage value U of the control side of the low-voltage shaft and high-voltage shaft double-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 the voltage loop and the current loop, the AC and DC axis voltage set values ​​u of the control side winding of the high-voltage shaft double-winding generator are obtained respectively. dH * and u qH * , the AC and DC axis voltage setting value u of the control side winding of the low voltage shaft double winding generator dL * and u qL * .

[0055] Specifically, the difference between the output reference voltage and the actual output voltage of the two dual-winding generators on the power side (i.e., U Hpref and U Hp The difference, U Lpref and U LpThe difference between the two windings is obtained by the PI regulator, and the d-axis reference current value i of the two double-winding generators is obtained. dH * and i dL * At the same time, the difference between the output reference voltage and the actual output voltage of the control side of the two dual-winding generators (i.e., U Href and U dc The difference, U Lref and U dc The difference between the two winding generators is obtained by the PI regulator. qH * and i qL * Then calculate the difference between the reference current and the actual current of the d-axis and q-axis (i.e. 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 AC and DC axis voltages of the control side winding of the high-voltage shaft double-winding generator is obtained after the PI regulator. dH * and u qH * , and the AC and DC axis voltage set value u of the control side winding of the low-voltage shaft double-winding generator dL * and u qL * .

[0056] Step 4: The AC and DC axis voltage set values ​​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 to achieve proportional distribution of the high-voltage and low-voltage shaft power extraction of the aviation dual-shaft engine. Specifically, for any dual-winding generator, the AC and DC axis voltage set values ​​are inversely transformed in combination with its rotor position information to determine the three-phase voltage set values ​​of the dual-winding generator in the three-phase stationary coordinate system, and then the control signals of the corresponding power switch tubes of the three-phase bridge arm are obtained through SVPWM modulation.

[0057] The above is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

Claims

1. A method for extracting power from an aviation dual-shaft engine based on a dual-winding generator, characterized in that: The power side winding of a dual-winding generator is connected to the AC bus of the aircraft engine, which is recorded 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 aircraft engine, which is recorded as a low-voltage shaft dual-winding generator. The control side windings of the two dual-winding generators are connected in parallel to the high-voltage DC bus. The method for the two dual-winding generators to extract power from the high and low voltage shafts of the aircraft engine includes: The output reference power of the control side windings of two double-winding generators is calculated according to 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, and then the AC and DC axis voltage given values ​​of the control side winding of the high-voltage shaft dual-winding generator and the AC and DC axis voltage given values ​​of the control side winding of the low-voltage shaft dual-winding generator are obtained through the step-by-step transmission of the voltage loop and the current loop; The AC and DC axis voltage set values ​​of the control side windings of the high-pressure shaft and low-pressure shaft dual-winding generators are output to the high-pressure shaft and low-pressure shaft dual-winding generators through SVPWM modulation to achieve proportional distribution of the high and low pressure shaft power extraction of the aviation dual-shaft engine.

2. The method for extracting power from an aviation dual-shaft engine based on a dual-winding generator according to claim 1, characterized in that: The method of calculating the output reference power of the control side windings of the two double-winding generators according to the power requirements of the various electrical loads includes: Considering the influence of power extraction on aviation dual-shaft engines, the output reference power of the control side windings of the two dual-winding generators satisfies: Where P Lref and P Href represents the output reference power of the control side winding of the low-voltage shaft and high-voltage shaft double-winding generator respectively; P represents the total power that the two double-winding generators need to output; k represents the proportional coefficient of the power extracted from the high-voltage and low-voltage shafts; P Lp and P Hp They respectively represent the power that needs to be output by the power side windings of the low-voltage shaft and high-voltage shaft double-winding generators.

3. The method for extracting power from an aviation dual-shaft engine based on a dual-winding generator according to claim 2, characterized in that: When considering the influence of power extraction on the aviation dual-shaft engine, the following formula is satisfied: Where P kl and P kh Represents the compressor power of the low-pressure shaft and the high-pressure shaft respectively; P tl and P th Represents the turbine power of the low-pressure shaft and the high-pressure shaft respectively; P L and P H denote the power extracted from the low-pressure shaft and the high-pressure shaft, respectively; η L and η H Represent the mechanical efficiency 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 an aviation dual-shaft engine based on a dual-winding generator according to claim 1, characterized in that: The output reference power is combined with the droop characteristic of the dual-winding generator to compensate 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 double-winding generator is combined with the droop characteristics of the double-winding generator of the corresponding shaft and the high-voltage DC bus voltage to obtain the voltage compensation value of the low-voltage shaft and high-voltage shaft double-winding generator; The voltage compensation values ​​of the low-voltage shaft and high-voltage shaft dual-winding generators are respectively compensated to the control side power loops of the low-voltage shaft and high-voltage shaft dual-winding generators, and added to the value obtained after the difference between the output reference power and the actual power passes through the PI regulator to obtain the output reference voltage values ​​of the control side of the low-voltage shaft and high-voltage shaft dual-winding generators.

5. The method for extracting power from an aviation dual-shaft 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 double-winding generator is combined with the droop characteristics of the double-winding generator of the corresponding shaft and the high-voltage DC bus voltage to obtain the voltage compensation value of the low-voltage shaft and high-voltage shaft double-winding generator, which is expressed as: Where U Lcom and U Hcom Respectively represent the voltage compensation value of the low-voltage shaft and high-voltage shaft double-winding generator; U dc Indicates the high-voltage DC bus voltage; P Lref and P Href Respectively represent the output reference power of the control side winding of the low-voltage shaft and high-voltage shaft double-winding generator; m L and m H They represent the droop coefficient of the low-voltage shaft double-winding generator and the droop coefficient of the high-voltage shaft double-winding generator respectively; for any double-winding generator, the droop coefficient is calculated as follows: Where 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 extracting power from an aviation dual-shaft engine based on a dual-winding generator according to claim 1, characterized in that: After compensation, the voltage loop control strategy of the high- and low-voltage shaft dual-winding generator is: 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 the PI regulator; The difference between the output reference voltage and the actual output voltage on the control side is calculated, and the q-axis reference current value of the dual-winding generator is obtained after passing through the PI regulator.

7. The method for extracting power from an aviation dual-shaft engine based on a dual-winding generator according to claim 1, characterized in that: After passing through the voltage loop, the current loop control strategy of the high and low voltage shaft dual winding generator is: The differences between the reference current and the actual current of the d-axis and q-axis are calculated respectively, and after passing through the PI regulator, the AC and DC axis voltage set values ​​of the control side winding of the high-voltage axis double-winding generator and the AC and DC axis voltage set values ​​of the control side winding of the low-voltage axis double-winding generator are obtained respectively.

8. The method for extracting power from an aviation dual-shaft engine based on a dual-winding generator according to claim 1, characterized in that: The method of outputting the AC and DC axis voltage set values ​​of the control side windings of the high-voltage shaft and low-voltage shaft dual-winding generators to the high-voltage shaft and low-voltage shaft dual-winding generators through SVPWM modulation is the same. For any dual-winding generator, the method includes: The AC and DC axis voltage given values ​​are subjected to inverse Park transformation in combination with the rotor position information of the dual-winding generator to determine the three-phase voltage given values ​​of the dual-winding generator in a three-phase stationary coordinate system, and then the control signals of the corresponding power switch tubes of the three-phase bridge arms are obtained through SVPWM modulation.

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