Turbine power generation system and control method

Abstract

The application discloses a turbine power generation system and a control method, which comprises an engine main body, a permanent magnet synchronous generator, a controllable rectification control device and an engine control device. The engine main body comprises a gas generator and a free turbine. The rotor of the permanent magnet synchronous generator is connected with the rotor of the free turbine. The input end of the engine control device is respectively connected with a system power demand instruction input end and an output power feedback end of the permanent magnet synchronous generator. The engine control device is connected with a fuel adjusting device for controlling, so as to adjust the fuel input amount of the gas generator and the rotating speed of the free turbine according to the power demand instruction and the generator output power feedback. The generator control device is connected with a rotating speed detection unit for collecting the actual value of the rotating speed of the free turbine, and is used for comparing the actual value of the rotating speed of the free turbine with a preset target value of the rotating speed of the free turbine, generating a load adjusting signal according to the rotating speed deviation, and controlling the working state of the controllable rectification control device so as to adjust the output current and the electromagnetic torque of the permanent magnet synchronous generator.

Description

Technical Field

[0001] This invention relates to the field of control technology for aircraft turbine power generation systems, and more particularly, to a turbine power generation system. Furthermore, this invention also relates to a control method comprising the aforementioned turbine power generation system. Background Technology

[0002] Hybrid power systems are a key development direction in the field of aviation propulsion. They combine aircraft engines, power batteries, electric motors, and electronic control units to output power, aiming to improve fuel economy, reduce emissions, and decrease noise. The turbine generator system, as the core high-power unit of the hybrid power system, integrates a free-turbine aircraft engine, an aircraft permanent magnet synchronous generator, and a controllable rectifier controller. It is responsible for converting the chemical energy of fuel into electrical energy to power the propulsion motor, airborne equipment, or energy storage systems.

[0003] In a free-turbine aero-engine driven permanent magnet generator system, the conventional control method adopts an architecture of "engine NP speed control + generator power / voltage control": The aero-engine free-turbine engine uses NP speed control mode, with the core objective of maintaining stable NP speed; the generator uses a permanent magnet generator structure, and its controller employs vector control. In practical applications, constant voltage control is often required to ensure the power supply stability of airborne electrical equipment; the eddy current system consists of the aero-engine, permanent magnet generator, and rectifier. To meet the requirements of aero-electric hybrid systems, the rectifier generally adopts a controllable method, and its topology is shown in [reference needed]. Figure 1 As shown; Traditional aircraft engines, to meet the flight requirements of helicopters, employ constant turbine speed control to maintain the helicopter's rotor speed at a fixed, baseline value. Building upon this constant turbine speed control, the engine control system proactively compensates for changes in fuel supply based on signals from the collective pitch lever—a process known as collective pitch compensation—to adapt to load variations caused by changes in rotor collective pitch. Figure 2 As shown; during the rapid pushing up or pulling down of the collective pitch lever, the helicopter rotor collective torque changes very quickly, causing a change in the power turbine speed Np. The engine control system determines the target acceleration rate Ngdot0 of the gas generator rotor based on the difference between Np and the reference value Np0 and the collective pitch compensation requirement. Then, using the difference between Ngdot0 and the actual acceleration rate Ngdot, it determines the change in fuel flow ΔWf and adjusts parameters such as the gas generator speed Ng to prevent the power turbine speed and rotor speed from exceeding the acceptable range. The existing technology has the following drawbacks: 1) Existing technology employs a discrete architecture for engine NP speed control and generator power / voltage control. The engine controller simultaneously acquires and responds to the free turbine NP speed signal. However, aero engines are heat engines, and fuel and gas circuits inherently exhibit response lag. The generator, relying on a controllable rectifier, possesses millisecond-level rapid adjustment capabilities. The control objectives, response bandwidth, and control timing of the two are severely mismatched. When the generator is loaded or unloaded, it rapidly changes its electromagnetic torque, causing reverse disturbance to the NP speed. The engine detects the speed fluctuation and adjusts the fuel accordingly with a lag, forming a closed-loop speed control that pulls on each other, causing continuous NP oscillation. This not only reduces the stability of the generator output but also exacerbates wear on the shaft system, bearings, and transmission components, shortening equipment lifespan. 2) Existing conventional optimization methods only involve tuning PID parameters and adding general feedforward compensation, which are local parameter fine-tuning. They do not fundamentally eliminate the disturbance of NP speed to the engine control loop, and cannot fundamentally solve the speed oscillation problem. They are difficult to adapt to the harsh operating conditions of frequent load increases and decreases, high dynamic disturbances, and high reliability of aviation hybrid systems. 3) Existing technologies such as free turbine engines, generator set coordinated control schemes, and permanent magnet rectifier decoupling schemes are all independent technologies. Even after simple combination, there are still problems such as cross-coupling of control loops, parameter mismatch, and limited dynamic response, which cannot meet the integrated control requirements of aviation turbine power generation systems. Summary of the Invention

[0004] This invention provides a turbine power generation system and control method to solve the technical problems in the prior art caused by deep coupling of the control loop in aero-turbine power generation systems, such as continuous oscillation of free turbine speed, limited dynamic response speed, dynamic overshoot, and large steady-state error.

[0005] According to one aspect of the present invention, a turbine power generation system is provided for use in a free-turbine aircraft engine, comprising: The engine body includes a gas generator and a free turbine. The free turbine is not mechanically connected to the gas generator, and the free turbine is driven to rotate by the high-temperature gas generated by the gas generator. A permanent magnet synchronous generator, wherein the rotor of the permanent magnet synchronous generator is connected to the rotor of the free turbine; A controllable rectifier control device is connected to a permanent magnet synchronous generator and an external DC bus or load; the controllable rectifier control device is used to adjust the output power and electromagnetic torque of the permanent magnet synchronous generator. An engine control unit, which is connected to the fuel regulation unit of the free turbine aircraft engine, is used to regulate the fuel input of the gas generator according to the system's power demand command and generator output power feedback, thereby regulating the speed of the free turbine rotor. The generator control device is used to compare the actual speed of the free turbine with the preset target speed of the free turbine, and generate a load adjustment signal based on the speed deviation to control the working state of the controllable rectifier control device, thereby adjusting the output current and electromagnetic torque of the permanent magnet synchronous generator.

[0006] As a further improvement to the above technical solution, the engine control device incorporates a power closed-loop regulation algorithm, which is a composite control algorithm combining proportional-integral control and feedforward compensation. The proportional-integral control is used to eliminate the steady-state deviation between the output power of the engine body and the power demand command of the system; the feedforward compensation is used to offset the dynamic errors caused by the fuel delay characteristics and airflow lag characteristics of the engine body.

[0007] As a further improvement to the above technical solution, the feedforward compensation adopts a linear fitting model based on the current operating parameters of the engine body or a neural network prediction model trained offline. The operating parameters include the current actual value of the gas generator speed, engine intake temperature, intake pressure, fuel pressure and exhaust temperature.

[0008] As a further improvement to the above technical solution, the generator control device incorporates a speed closed-loop regulation algorithm, which is a proportional-integral control algorithm based on rotor field-oriented vector control. The generator control device decomposes the stator current of the permanent magnet synchronous generator into an excitation current component and a torque current component, and achieves decoupled control of the electromagnetic torque by adjusting the excitation current component and the torque current component respectively.

[0009] According to another aspect of the present invention, a control method is also provided, comprising the above-described turbine power generation system, the control method comprising: S1. The engine control unit receives the system power demand command and parses the system power demand command into the target speed of the gas generator; S2. The engine control unit adjusts the fuel input of the gas generator according to the target speed of the gas generator, controls the speed of the gas generator, and makes the output power of the engine main body track the power demand command of the system. S3. The generator control device collects the actual speed value of the free turbine in real time, compares it with the preset speed target value, and independently adjusts the output current of the controllable rectifier control device according to the speed deviation. S4. Feed back the actual output power value of the permanent magnet synchronous generator to the engine control device, and the engine control device dynamically corrects the target speed or fuel input of the gas generator according to the deviation between the actual output power value and the system power demand command; S5. Repeat steps S1-S4.

[0010] As a further improvement to the above technical solution, step S2 employs a composite control algorithm combining proportional-integral control with aerospace-specific feedforward compensation. Step S2 includes: S21. Calculate the power deviation; S22. Input the power deviation into the proportional-integral controller to calculate the base adjustment amount; S23. Collect the current aviation operating parameters of the engine body and calculate the feedforward compensation amount through the feedforward compensation model; S24. The basic adjustment amount is superimposed with the feedforward compensation amount and output as the final fuel adjustment command to the gas generator.

[0011] As a further improvement to the above technical solution, in step S22, the value range of the proportional coefficient is 0.8 to 1.5, and the value range of the integral time is 0.2 to 0.4 seconds.

[0012] As a further improvement to the above technical solution, the speed regulation in step S3 adopts a proportional-integral control algorithm based on rotor field-oriented vector control, with added speed feedforward compensation; step S3 includes: S31. The actual speed of the free turbine is collected in real time by the speed detection unit, and the difference between the actual speed and the preset speed target value is calculated to obtain the speed deviation; S32. Input the speed deviation into the proportional-integral speed controller to calculate the electromagnetic torque setpoint; S33. Based on the rotor field-oriented vector control principle, the generator stator current is decomposed into excitation current component and torque current component. The torque current component is adjusted to track the electromagnetic torque setpoint through current closed-loop control, thereby controlling the generator output electromagnetic torque.

[0013] As a further improvement to the above technical solution, step S32 includes: the speed ring proportional coefficient ranges from 1.5 to 2.5, and the speed ring integral time ranges from 0.1 to 0.25 seconds; the current ring proportional coefficient ranges from 8.0 to 12.0, and the current ring integral time ranges from 0.03 to 0.08 seconds.

[0014] As a further improvement to the above technical solution, the power regulation in step S4 adopts low-pass filtering and power loop proportional-integral control. Step S4 includes: S41. Power deviation calculation; S42. Power deviation filtering; S43. Calculation of power closed-loop regulation: Input the filtered power deviation into the power proportional-integral controller to calculate the power regulation. The proportional coefficient of the power loop is in the range of 0.5 to 1.0, and the integral time is in the range of 1 to 3 seconds. S44. Correct the target speed of the gas generator; S45. Update the fuel adjustment command to dynamically adjust the fuel input of the gas generator.

[0015] The present invention has the following beneficial effects: In this turbine power generation system, the gas generator and free turbine of the engine body are not mechanically connected; energy is transferred only through high-temperature gas. The fuel supply to the gas generator is regulated by the engine controller, and the gas generator outputs the corresponding gas energy according to the power demand to drive the free turbine. The gas generator rotor control is unaffected by the free turbine speed throughout the entire process. The free turbine rotor is rigidly and directly connected to the permanent magnet synchronous generator rotor. The generator control unit independently completes the closed-loop control of the free turbine speed. Through a controllable rectifier control device, the frequency-converted and voltage-converted AC power output from the permanent magnet synchronous generator is rectified into controllable DC power, and the output power and electromagnetic torque of the permanent magnet synchronous generator are adjusted to achieve pure speed closed-loop control, independently offsetting load disturbances and maintaining the stability of the free turbine speed. The engine control unit receives the input system power demand command and the output power of the permanent magnet synchronous generator, but does not sample the free turbine speed signal, and outputs the fuel supply / discharge command. The gas path opening adjustment command controls the gas generator speed, achieving pure power closed-loop control. This ensures the engine output power matches system requirements without participating in speed regulation. The engine control unit and generator control unit interact only through power signals, completely decoupling the two control loops. This eliminates any interdependence between the engine and generator controllers. Even if the generator control unit fails, the engine control unit can still maintain engine output power according to power demand commands, allowing the system to operate at a degraded speed. Conversely, even if the engine control unit fails, the generator control unit can maintain stable free turbine speed within a pre-set power range, providing time for fault diagnosis and switching, thus improving the system's fault tolerance and maintainability. The engine control unit completely ignores free turbine speed signals, cutting off the disturbance path of the generator's rapid adjustment electromagnetic torque on the engine control loop. Under various load disturbance conditions, the free turbine... There was no continuous oscillation in the rotational speed, and the steady-state error control of the rotational speed was stable. In this system, the free turbine speed regulation is achieved by the generator control device. Utilizing the millisecond-level electromagnetic response characteristics of the permanent magnet synchronous generator and the controllable rectifier, the dynamic response of the system to load changes is entirely handled by the high-bandwidth electrical circuit, no longer limited by the engine's second-level mechanical response delay. The actual test results show that under a 50% load step disturbance, the free turbine speed recovery time of this system is less than 50 milliseconds, while the recovery time of traditional control schemes is usually more than 2 seconds, improving the response speed by more than 10 times. In addition, since the free turbine speed is maintained constant independently by the generator control device, the engine body does not need to be frequently adjusted due to fluctuations in the free turbine speed. Therefore, it can always operate near its optimal efficiency speed point, which can reduce the engine's average fuel consumption rate by 8% to 15%, while reducing the wear and thermal fatigue of mechanical parts and extending the engine's overhaul interval and maintenance cycle.

[0016] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a topology diagram of a controllable rectifier controller in the existing technology; Figure 2 This is a schematic diagram of the control principle of a turboshaft engine in the prior art; Figure 3 This is a simplified overall structural diagram of a turbine power generation system according to a preferred embodiment of the present invention; Figure 4 This is a schematic diagram of the control architecture of the eddy current system according to a preferred embodiment of the present invention. Detailed Implementation

[0018] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0019] Figure 3 This is a simplified overall structural diagram of a turbine power generation system according to a preferred embodiment of the present invention; Figure 4 This is a schematic diagram of the control architecture of the eddy current system according to a preferred embodiment of the present invention; like Figure 3 and Figure 4 As shown, the turbine power generation system of this embodiment is applied to a free turbine aircraft engine and includes: The engine body includes a gas generator and a free turbine. There is no mechanical connection between the free turbine and the gas generator. The free turbine is driven to rotate by the high-temperature gas generated by the gas generator. A permanent magnet synchronous generator, in which the rotor of the permanent magnet synchronous generator is connected to the rotor of a free turbine, and the free turbine drives the permanent magnet synchronous generator. The controllable rectifier control device can be implemented using existing controllable rectifier controllers. The AC input terminal of the controllable rectifier control device is electrically connected to the three-phase AC output terminal of the permanent magnet synchronous generator, and the DC output terminal of the controllable rectifier control device is used to connect to an external DC bus or load. The controllable rectifier control device is used to rectify the frequency-converted and voltage-converted AC power output by the permanent magnet synchronous generator into controllable DC power, and to adjust the output power and electromagnetic torque of the permanent magnet synchronous generator. The engine control unit, or EC (engine controller), has its input terminals connected to the system power demand command input terminal and the output power feedback terminal of the permanent magnet synchronous generator, respectively. The engine control unit is connected to the fuel regulation device of the free turbine aero-engine and is used to regulate the fuel input of the gas generator according to the power demand command and the generator output power feedback, thereby regulating the speed of the free turbine rotor. The generator control unit, or GC (generator controller), is connected to a speed detection unit for real-time acquisition of the actual speed of the free turbine. It compares the actual speed of the free turbine with the preset target speed of the free turbine, and generates a load adjustment signal based on the speed deviation to control the working state of the controllable rectifier control unit, thereby adjusting the output current and electromagnetic torque of the permanent magnet synchronous generator.

[0020] The gas generator's rotor shaft is defined as the NG shaft, and its rotational speed is defined as the NG speed. The gas generator also includes a compressor, combustion chamber, main turbine, and other structures. The free turbine rotor is defined as the NP shaft, and its rotational speed is defined as the NP speed. The permanent magnet synchronous generator adopts an aerospace-grade permanent magnet synchronous generator. The rotor of the permanent magnet synchronous generator is equipped with high-performance permanent magnets, eliminating the need for an external excitation power supply. It has the advantages of simple structure, high efficiency, and high power density. The system controller adopts internal and external dual-loop control. The voltage loop (the outer loop can be a power loop depending on the actual system configuration) uses a PI regulator to control the DC side voltage to ensure DC voltage stability. The current loop uses a PI controller to control the AC side current, enabling the AC side current to accelerate the response speed while meeting harmonic content requirements and system power factor requirements. The speed detection unit uses existing speed sensors, such as magnetoelectric speed sensors and Hall effect sensors. Understandably, in this turbine power generation system, the gas generator and free turbine of the engine body are not mechanically connected; energy is transferred only through high-temperature gas. The gas generator's fuel supply is regulated by the engine controller, and it outputs corresponding gas energy only according to power demand to drive the free turbine. The gas generator rotor control is unaffected by the free turbine speed throughout the entire process. The free turbine rotor is rigidly and directly connected to the permanent magnet synchronous generator rotor. The generator control device independently completes the closed-loop control of the free turbine speed. Through a controllable rectifier control device, it rectifies the frequency-converted and voltage-converted AC power output from the permanent magnet synchronous generator into controllable DC power and adjusts the output power and electromagnetic torque of the permanent magnet synchronous generator to achieve pure speed closed-loop control, independently offsetting load disturbances and maintaining the stability of the free turbine speed. The engine control device receives the input system power demand command and the output power of the permanent magnet synchronous generator, does not sample the free turbine speed signal, and outputs the fuel supply / discharge command. The gas path opening adjustment command controls the gas generator speed, achieving pure power closed-loop control. This ensures the engine output power matches system requirements without participating in speed regulation. The engine control unit and generator control unit interact only through power signals, completely decoupling the two control loops. This eliminates any interdependence between the engine and generator controllers. Even if the generator control unit fails, the engine control unit can still maintain engine output power according to power demand commands, allowing the system to operate at a degraded speed. Conversely, even if the engine control unit fails, the generator control unit can maintain stable free turbine speed within a pre-set power range, providing time for fault diagnosis and switching, thus improving the system's fault tolerance and maintainability. The engine control unit completely ignores free turbine speed signals, cutting off the disturbance path of the generator's rapid adjustment electromagnetic torque on the engine control loop. Under various load disturbance conditions, the free turbine... There was no continuous oscillation in the rotational speed, and the steady-state error control of the rotational speed was stable. In this system, the free turbine speed regulation is achieved by the generator control device. Utilizing the millisecond-level electromagnetic response characteristics of the permanent magnet synchronous generator and the controllable rectifier, the dynamic response of the system to load changes is entirely handled by the high-bandwidth electrical circuit, no longer limited by the engine's second-level mechanical response delay. The actual test results show that under a 50% load step disturbance, the free turbine speed recovery time of this system is less than 50 milliseconds, while the recovery time of traditional control schemes is usually more than 2 seconds, improving the response speed by more than 10 times. In addition, since the free turbine speed is maintained constant independently by the generator control device, the engine body does not need to be frequently adjusted due to fluctuations in the free turbine speed. Therefore, it can always operate near its optimal efficiency speed point, which can reduce the engine's average fuel consumption rate by 8% to 15%, while reducing the wear and thermal fatigue of mechanical parts and extending the engine's overhaul interval and maintenance cycle.

[0021] It should be noted that simply cutting off the engine controller's response to NP speed will cause the engine power control loop to lose its ability to sense load changes, resulting in power tracking lag. This system provides load change information to the engine controller by unidirectionally feeding back the generator output power to the engine controller without introducing NP speed disturbances, enabling the engine controller to slowly adjust its power output. Both are indispensable: without a power closed loop, the decoupled architecture will lead to steady-state power deviation; without a decoupled architecture, the power closed loop will introduce NP speed disturbances. In some preferred embodiments, the engine control device incorporates a power closed-loop regulation algorithm, which is a composite control algorithm combining proportional-integral control and feedforward compensation. The proportional-integral control is used to eliminate the steady-state deviation between the engine's output power and the system power demand command; the feedforward compensation is used to offset the dynamic errors caused by the engine's fuel delay characteristics and airflow lag characteristics. Furthermore, the feedforward compensation employs a linear fitting model based on the current operating parameters of the engine body or a neural network prediction model trained offline. These operating parameters include the actual current gas generator speed, engine intake air temperature, intake air pressure, fuel pressure, and exhaust temperature. General feedforward compensation is typically based on engine speed deviation, which cannot be directly applied in this decoupled architecture without free turbine speed feedback. This system designs a dedicated feedforward model specifically for the fuel lag and gas path lag characteristics of aero-engines. Its input parameters (NG speed, intake air temperature, intake air pressure, fuel pressure, and exhaust temperature) do not involve NP speed, making it perfectly compatible with the decoupled architecture. If this composite algorithm is not used, a pure decoupled architecture would result in power tracking lag. In some preferred embodiments, the generator control device incorporates a speed closed-loop regulation algorithm, which is a proportional-integral control algorithm based on rotor field-oriented vector control. The generator control device decomposes the stator current of the permanent magnet synchronous generator into excitation current components and torque current components, and achieves decoupled control of electromagnetic torque by adjusting the excitation current components and torque current components separately. The generator controller independently assumes all responsibility for NP speed regulation, therefore its control algorithm must have extremely high dynamic response capability and disturbance rejection capability. The speed loop PI parameters (Kp=1.5~2.5, Ti=0.1~0.25s) and current loop PI parameters (Kp=8.0~12.0, Ti=0.03~0.08s) and speed feedforward compensation customized for the generator controller in this system are all calibrated for the high-speed response characteristics and NP-axis transient disturbance characteristics of the aviation permanent magnet synchronous generator, and can achieve millisecond-level speed regulation under the decoupled architecture of this system. If general PI parameters are used, the performance requirements of the decoupled architecture for the generator controller cannot be met.

[0022] This system eliminates the continuous oscillation of NP speed, significantly reducing the alternating load on transmission components such as the free turbine shaft, coupling, and generator bearings. Simulation analysis and preliminary bench testing show that shaft fatigue load is reduced by more than 60%, which can significantly extend the service life of aviation equipment and reduce the total life cycle maintenance cost. It is specially designed for the harsh operating conditions of aviation scenarios, such as wide temperature range (-60℃ to +50℃), altitude changes (from ground to 12,000 meters), and high frequency of loading and unloading: it can automatically adjust control parameters according to environmental parameters; the feedforward compensation model is calibrated based on aero-engine bench data; and the PI parameters are optimized for the fuel supply response characteristics of aero-engines. Therefore, this system has significantly better stability and reliability than general ground solutions in scenarios such as aviation hybrid power systems and airborne power generation.

[0023] On the other hand, a preferred embodiment of the present invention also provides a control method applied to the above-mentioned turbine power generation system, the control method comprising: S1. The engine control unit receives the system power demand command and parses it into the target speed of the gas generator. Specifically, based on the flight phase (takeoff, cruise, landing, etc.) and propulsion power requirements, it generates a system power demand command P_set (in kW). P_set can be sent to the engine controller via the aviation CAN bus. The engine controller converts P_set into the target NG speed of the gas generator NG_set according to the engine power-speed calibration curve pre-stored in memory. S2. The engine control unit adjusts the fuel input of the gas generator according to the target speed of the gas generator, controls the speed of the gas generator, and makes the output power of the main engine track the power demand command of the system; it adopts a composite control algorithm of PI control + aviation-specific feedforward compensation to adjust the fuel supply and control the speed of the NG shaft so that the engine output power matches P_set; the NP speed is not detected throughout this step; the gas energy drives the free turbine NP shaft to rotate, driving the permanent magnet synchronous generator to generate electricity; S3. The generator control unit GC collects the actual speed value NP_actual of the free turbine in real time, compares it with the preset speed target value, calculates the speed deviation ΔNP = NP_set - NP_actual, and independently adjusts the output current of the controllable rectifier control unit according to the speed deviation; through the high bandwidth vector control algorithm, it adjusts the current of the controllable rectifier and the generator stator to correct the NP speed and complete the speed closed loop. S4. Feed back the actual output power value P_output of the permanent magnet synchronous generator to the engine control unit EC. The engine control unit dynamically corrects the target speed or fuel input of the gas generator based on the deviation between the actual output power value and the system power demand command, forming a global power closed loop to dynamically compensate for load changes. S5. Repeat steps S1-S4 to achieve steady-state operation of the system.

[0024] In some preferred embodiments, step S2 employs a composite control algorithm combining proportional-integral control with aerospace-specific feedforward compensation. Step S2 includes: S21. Calculate the power deviation e_P = P_set - P_act; S22. Input the power deviation into the proportional-integral controller to calculate the basic adjustment amount; S23. Collect the current aviation operating condition parameters of the engine body and calculate the feedforward compensation amount through the feedforward compensation model; collect aviation operating condition parameters: current actual value of NG speed NG_act, engine intake air temperature T_in, intake air pressure P_in, fuel pressure P_fuel, exhaust temperature T_exh. The collection method is implemented with reference to existing technology, and will not be described in detail. S24. The basic adjustment amount and the feedforward compensation amount are superimposed to form the final fuel adjustment command, which is then output to the gas generator. A composite control algorithm combining PI control and aviation-specific feedforward compensation is adopted to adapt to the inherent characteristics of aviation free turbine engines, such as fuel supply lag and slow gas path response. It is used in conjunction with the decoupled architecture of "EC without NP speed input". The deviation e_P between the actual output power and the given power is collected and input to the PI regulator. At the same time, feedforward compensation is introduced in combination with aviation engine-specific operating parameters to offset the dynamic lag unique to aviation scenarios. In some preferred embodiments, in step S22, the proportional coefficient ranges from 0.8 to 1.5 to adapt to the steady-state accuracy of the aero-engine and avoid fuel overshoot. The integral time ranges from 0.2 to 0.4 seconds to match the response speed of the aviation fuel supply and suppress integral saturation. The range is an optimized range determined by bench calibration tests based on the response characteristics of the fuel supply system of the free turbine aero-engine, the rotor inertia of the gas generator, and the dynamic requirements under aviation conditions. Within this range, the system can achieve the best balance between steady-state accuracy and dynamic response, avoiding power oscillation caused by proportional overshoot and regulation lag caused by integral saturation. By adopting PI parameters and a feedforward compensation model specifically customized for the aero-turbine generator system, the engine output power can quickly and stably track the power command, avoiding power output fluctuations and ensuring the steady-state accuracy of the power supply. The steady-state power error on the engine side is ≤ ±0.5%, and the steady-state error of the NP speed on the generator side is ≤ ±0.8%. The control accuracy is significantly better than the existing technical solutions using general parameters. The global power closed loop further eliminates steady-state deviations caused by environmental changes, component aging, etc. In some preferred embodiments, the speed adjustment in step S3 employs a proportional-integral control algorithm based on rotor field-oriented vector control, with added speed feedforward compensation; step S3 includes: S31. The actual speed of the free turbine is collected in real time by the speed detection unit, and the difference between the actual speed and the preset speed target value is calculated to obtain the speed deviation ΔNP = NP_set - NP_actual; S32. Input the speed deviation into the speed proportional-integral regulator to calculate the electromagnetic torque setpoint; further, calculate the speed deviation change rate Δe_N, make advance compensation based on the NP speed deviation change rate Δe_n, and superimpose the two to obtain the electromagnetic torque setpoint, specifically to offset the transient torque disturbance caused by frequent load increases and decreases under aviation conditions; S33. Based on the rotor field-oriented vector control principle, the generator stator current is decomposed into excitation current component and torque current component. The torque current component is adjusted to track the electromagnetic torque setpoint through current closed-loop control, thereby controlling the generator output electromagnetic torque. By introducing a speed feedforward compensation stage, the torque current component is adjusted in advance according to the speed deviation change rate, which speeds up the response and counteracts the transient torque disturbance generated during loading and unloading. Combined with measured data, the steady-state error of the free turbine speed is ensured to be controlled within the preset range. The steady-state error of the NP speed is controlled within ±0.8%, and the speed adjustment is completed in milliseconds. Understandably, the generator output power is fed back to the EC in one direction only for power correction and does not transmit any speed-related information. This closed loop is designed to support the "dual-loop fully decoupled architecture" and achieve dynamic power compensation. In some preferred embodiments, step S32 includes: the speed loop proportional coefficient is in the range of 1.5 to 2.5, and the speed loop integral time is in the range of 0.1 to 0.25 seconds, for calibrating the transient disturbance of the NP axis and suppressing speed overshoot; the current loop proportional coefficient is in the range of 8.0 to 12.0, and the current loop integral time is in the range of 0.03 to 0.08 seconds, to match the high-speed response characteristics of the stator current of the aircraft generator.

[0025] In some preferred embodiments, the power regulation in step S4 employs low-pass filtering and power loop proportional-integral control, and step S4 includes: S41. Power deviation calculation; S42. Power deviation filtering; S43. Calculation of power closed-loop regulation: Input the filtered power deviation into the power proportional-integral controller to calculate the power regulation. The proportional coefficient of the power loop is in the range of 0.5 to 1.0, and the integral time is in the range of 1 to 3 seconds. It should be noted that the response time constant (in seconds) of the power closed-loop PI regulator is much larger than the response time constant (in milliseconds) of the NP speed closed-loop PI regulator. The two differ by more than two orders of magnitude in time scale, thereby achieving full decoupling between the power control loop and the speed control loop in the frequency domain and avoiding mutual interference between the two control loops. S44. Correct the target speed of the gas generator; S45. Update the fuel regulation command to dynamically adjust the fuel input of the gas generator so that the output power of the engine tracks the system power demand command on a slow time scale.

[0026] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A turbine power generation system applied to a free-turbine aircraft engine, characterized in that, include: The engine body includes a gas generator and a free turbine. The free turbine is not mechanically connected to the gas generator, and the free turbine is driven to rotate by the high-temperature gas generated by the gas generator. A permanent magnet synchronous generator, wherein the rotor of the permanent magnet synchronous generator is connected to the rotor of the free turbine; A controllable rectifier control device is connected to a permanent magnet synchronous generator and an external DC bus or load; the controllable rectifier control device is used to adjust the output power and electromagnetic torque of the permanent magnet synchronous generator. An engine control unit, which is connected to the fuel regulation unit of the free turbine aircraft engine, is used to regulate the fuel input of the gas generator according to the system's power demand command and generator output power feedback, thereby regulating the speed of the free turbine rotor. The generator control device is used to compare the actual speed of the free turbine with the preset target speed of the free turbine, and generate a load adjustment signal based on the speed deviation to control the working state of the controllable rectifier control device, thereby adjusting the output current and electromagnetic torque of the permanent magnet synchronous generator.

2. The turbine power generation system according to claim 1, characterized in that, The engine control device has a built-in power closed-loop regulation algorithm, which is a composite control algorithm of proportional-integral control and feedforward compensation. The proportional-integral control is used to eliminate the steady-state deviation between the output power of the engine body and the power demand command of the system; the feedforward compensation is used to offset the dynamic error caused by the fuel delay characteristics and air path lag characteristics of the engine body.

3. The turbine power generation system according to claim 2, characterized in that, The feedforward compensation adopts a linear fitting model based on the current operating parameters of the engine body or a neural network prediction model trained offline. The operating parameters include the current actual value of the gas generator speed, engine intake temperature, intake pressure, fuel pressure and exhaust temperature.

4. The turbine power generation system according to claim 1, characterized in that, The generator control device has a built-in speed closed-loop regulation algorithm, which is a proportional-integral control algorithm based on rotor field-oriented vector control. The generator control device decomposes the stator current of the permanent magnet synchronous generator into excitation current component and torque current component, and achieves decoupled control of electromagnetic torque by adjusting the excitation current component and torque current component respectively.

5. A control method, characterized in that, The control method, using the turbine power generation system as described in any one of claims 1-4, comprises: S1. The engine control unit receives the system power demand command and parses the system power demand command into the target speed of the gas generator; S2. The engine control unit adjusts the fuel input of the gas generator according to the target speed of the gas generator, controls the speed of the gas generator, and makes the output power of the engine main body track the power demand command of the system. S3. The generator control device collects the actual speed value of the free turbine in real time, compares it with the preset speed target value, and independently adjusts the output current of the controllable rectifier control device according to the speed deviation. S4. Feed back the actual output power value of the permanent magnet synchronous generator to the engine control device, and the engine control device dynamically corrects the target speed or fuel input of the gas generator according to the deviation between the actual output power value and the system power demand command; S5. Repeat steps S1-S4.

6. The control method according to claim 5, characterized in that, Step S2 employs a composite control algorithm combining proportional-integral control with aerospace-specific feedforward compensation. Step S2 includes: S21. Calculate the power deviation; S22. Input the power deviation into the proportional-integral controller to calculate the basic adjustment amount; S23. Collect the current aviation operating parameters of the engine body and calculate the feedforward compensation amount through the feedforward compensation model; S24. The basic adjustment amount is superimposed with the feedforward compensation amount and output as the final fuel adjustment command to the gas generator.

7. The control method according to claim 6, characterized in that, In step S22, the proportional coefficient ranges from 0.8 to 1.5, and the integral time ranges from 0.2 to 0.4 seconds.

8. The control method according to claim 5, characterized in that, The speed regulation in step S3 adopts a proportional-integral control algorithm based on rotor field-oriented vector control, with added speed feedforward compensation; step S3 includes: S31. The actual speed of the free turbine is collected in real time by the speed detection unit, and the difference between the actual speed and the preset speed target value is calculated to obtain the speed deviation; S32. Input the speed deviation into the proportional-integral speed controller to calculate the electromagnetic torque setpoint; S33. Based on the rotor field-oriented vector control principle, the generator stator current is decomposed into excitation current component and torque current component. The torque current component is adjusted to track the electromagnetic torque setpoint through current closed-loop control, thereby controlling the generator output electromagnetic torque.

9. The control method according to claim 8, characterized in that, Step S32 includes: the speed loop proportional coefficient ranges from 1.5 to 2.5, and the speed loop integral time ranges from 0.1 to 0.25 seconds; the current loop proportional coefficient ranges from 8.0 to 12.0, and the current loop integral time ranges from 0.03 to 0.08 seconds.

10. The control method according to claim 5, characterized in that, The power regulation in step S4 employs low-pass filtering and power loop proportional-integral control. Step S4 includes: S41. Power deviation calculation; S42. Power deviation filtering; S43. Calculation of power closed-loop regulation: Input the filtered power deviation into the power proportional-integral controller to calculate the power regulation. The proportional coefficient of the power loop is in the range of 0.5~1.0, and the integral time is in the range of 1~3 seconds. S44. Correct the target speed of the gas generator; S45. Update the fuel adjustment command to dynamically adjust the fuel input of the gas generator.

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