A Cooperative Control Method for Intelligent Power Generation Units in Ship Hybrid Power Generation Based on Torque Observer

Abstract

The purpose of this invention is to provide a collaborative control method for a ship hybrid intelligent power generation unit based on a torque observer. The method includes an ammonia fuel engine and a three-phase permanent magnet synchronous motor. The ammonia fuel engine uses throttle torque control, and the three-phase permanent magnet synchronous motor uses speed control. The method employs a pre-set smoke limit lookup table, an no-load ammonia injection quantity MAP lookup table, a speed-regulating ammonia injection quantity MAP lookup table, and a feedforward ammonia injection quantity dynamic correction lookup table. The smoke limit lookup table uses boost pressure, boost temperature, and airflow as inputs; the no-load ammonia injection quantity MAP lookup table uses cooling water temperature and estimated speed as inputs; the speed-regulating ammonia injection quantity MAP lookup table uses pedal position and estimated speed as inputs; and the feedforward ammonia injection quantity dynamic correction lookup table uses estimated speed and estimated torque as inputs. This method comprehensively optimizes the ammonia injection quantity to control the ammonia engine speed. This invention estimates the engine speed using the motor speed and the crankshaft angle position using the motor rotor position, thereby saving on the cost of engine crankshaft sensors.

Description

Technical Field

[0001] The present invention relates to a ship control method, specifically a ship hybrid power control method. Background Technology

[0002] Currently, marine power systems, which are mainly based on diesel engines, have the disadvantages of high pollution, low energy consumption, and high carbon emissions. Therefore, there is an urgent need to find a low-carbon and efficient power system to meet the increasingly stringent carbon reduction requirements and adapt to the future goals of low-carbonization and even zero carbon.

[0003] Ammonia fuel, as a clean fuel, is widely used in the chemical industry. As a zero-carbon fuel, it has also attracted increasing attention in the marine propulsion field in recent years. Although the concept of ammonia fuel engines has been proposed in the shipbuilding industry, mature products are still lacking due to technological limitations. On the one hand, there is a lack of comprehensive research on the performance of ammonia fuel engines; on the other hand, there is no clear technical solution for matching ammonia fuel engines with appropriate power systems. Therefore, the research and development of ammonia fuel engines is still in its initial stage, and hybrid power systems for ammonia fuel engines are currently a technological void.

[0004] Marine hybrid power systems combine the advantages of traditional internal combustion engine propulsion and pure electric propulsion. Hybrid systems offer significant advantages in overall energy efficiency, energy conservation and emission reduction, and vibration and noise reduction. Furthermore, compared to pure electric propulsion systems, they can achieve long driving ranges with smaller capacity batteries at a lower cost. Hybrid systems based on ammonia fuel engines can meet the requirements of zero-carbon power while mitigating the low efficiency and cold-start difficulties of ammonia fuel engines. The introduction of an electric motor can also improve the dynamic characteristics of ammonia fuel engines, achieving complementary advantages from multiple power sources. Hybrid systems based on ammonia fuel engines will become one of the best power forms for future zero-carbon power.

[0005] Currently, power generation units based on ammonia fuel engines simply mechanically couple the ammonia fuel engine and the motor. Their control methods are completely independent of each other, which leads to uncoordinated control and wasted hardware. At the same time, the power generation unit as a whole needs to be coordinated and controlled as a whole to maximize its advantages. Summary of the Invention

[0006] The purpose of this invention is to provide a collaborative control method for intelligent hybrid power generation units in ships based on a torque observer, which can overcome the shortcomings of poor control performance caused by separate control of the engine and motor in traditional hybrid power generation units.

[0007] The objective of this invention is achieved as follows:

[0008] This invention discloses a collaborative control method for a ship hybrid intelligent power generation unit based on a torque observer. The method includes an ammonia fuel engine and a three-phase permanent magnet synchronous motor. The ammonia fuel engine employs throttle torque control, while the three-phase permanent magnet synchronous motor employs speed control. The method utilizes tables for pre-set smoke limit limits, no-load ammonia injection MAP, speed-regulating ammonia injection MAP, and feedforward ammonia injection dynamic correction. The smoke limit limit lookup uses boost pressure, boost temperature, and airflow as inputs; the no-load ammonia injection MAP uses cooling water temperature and estimated speed as inputs; the speed-regulating ammonia injection MAP uses pedal position and estimated speed as inputs; and the feedforward ammonia injection dynamic correction lookup uses estimated speed and estimated torque as inputs. This comprehensive optimization of ammonia injection quantity controls the ammonia engine speed. Furthermore, the centerline of the shaft corresponding to the wide tooth clearance of the flywheel signal disc in the ammonia fuel engine is aligned with the spatial axis of phase A of the stator winding of the three-phase permanent magnet synchronous motor. Simultaneously, phase A is aligned with the direct axis in both the three-phase coordinate system and the quadrature-direct axis coordinate system.

[0009] The present invention may also include:

[0010] 1. The speed control of a three-phase permanent magnet synchronous motor includes a position sensor, a torque observer, a speed PID loop, and a current PID loop. The position sensor measures the rotor position of the motor, and the torque observer observes the electromagnetic torque. The torque observer adopts the form of an extended state observer. The speed is controlled by a dual-loop PID loop, and the current is controlled by a dual-loop PID loop.

[0011] The torque observer expression is:

[0012]

[0013]

[0014]

[0015]

[0016]

[0017] Where: K active For active flux; L d It is a direct-axis inductor; L q For axial inductance; r req For virtual resistance; i d For stator direct-axis current; i q For stator quadrature-axis current; K E For permanent magnet flux linkage; n is the estimated motor speed. pp J is the number of pole pairs of the motor; s This refers to the moment of inertia of the motor. This is the estimated load torque value; l p ε is the torque observer gain; ε is the error operator.

[0018] 2. The conversion relationship between the estimated speed of the ammonia fuel engine and the estimated speed of the electric motor is as follows:

[0019]

[0020] Where: n e For ammonia fuel engine speed; θ e θ is the crankshaft rotation angle; r T is the rotor angle of the motor; e For engine torque; η m For motor efficiency.

[0021] 3. Sample the three-phase current of the three-phase permanent magnet synchronous motor and convert it into the corresponding α and β axis currents in the Clark coordinate system. Using the α and β axis currents as inputs and the motor rotor angle sampled by the position sensor as input, perform Park transformation on the stator currents under the α and β axes to obtain the stator current under the dq axis. Using the stator current under the dq axis and the motor speed as inputs, calculate the estimated motor speed and estimated load torque through the torque observer expression. The difference between the actual motor speed and the given speed is fed into the speed PID loop. The speed PID loop outputs the reference dq axis current, and the difference between the reference dq axis current and the actual stator dq axis current fed back by the motor is passed through the direct axis current PID loop and the quadrature axis current PID loop to output the given d and q axis reference voltage. The SVPWM waveform generation module sends a signal to the inverter to control the motor stator current to control the speed.

[0022] 4. The actual motor speed obtained from motor control and the estimated motor load torque are compared using the formula... The values ​​are converted to ammonia engine speed and load torque. The ammonia engine speed and torque are used as inputs to query the dynamic correction table for feedforward ammonia injection quantity to obtain the feedforward value. The pedal position obtained from the required torque and the engine speed are used as inputs to query the speed-regulating ammonia injection quantity MAP table as the increment. The coolant temperature and engine speed are used as inputs to query the no-load ammonia injection quantity MAP table to obtain the no-load ammonia injection quantity. The boost pressure, boost temperature, and air flow are used as inputs to query the smoke limit as the ammonia injection quantity limit. The feedforward ammonia injection quantity, speed-regulating ammonia injection quantity, and no-load ammonia injection quantity are accumulated. With the smoke limit as the limit, the MIN / MAX strategy is used to output the ammonia injection quantity required by the engine to complete the engine throttle torque control.

[0023] The advantages of this invention are:

[0024] 1. This invention proposes a ship hybrid power intelligent power generation unit and cooperative control strategy based on a torque observer. In terms of hardware design, the crankshaft sensor of the ammonia fuel engine is eliminated. Instead, the center line of the wide-toothed signal disk at the crankshaft flywheel end is aligned with the spatial axis of the three-phase permanent magnet motor in the A-direction. This design allows for the calculation of the crankshaft angle of the ammonia engine by obtaining the position of the motor rotor, without the need for complex conversions. This saves on sensor hardware costs and significantly reduces the pressure on the engine controller signal processing, saving computational space.

[0025] 2. The hybrid intelligent power generation unit collaborative control strategy adopts engine throttle torque control and motor speed control, which fully considers the dynamic characteristics of both. That is, it takes advantage of the motor's fast dynamic response to quickly reach a high speed state, while the engine uses throttle control to load, which can make the engine work in the high speed range as much as possible, resulting in better engine economy.

[0026] 3. The three-phase permanent magnet synchronous motor adopts a speed control method and uses an extended state observer to estimate the motor speed and torque. The estimated torque of the motor can be used as a feedforward input for the ammonia fuel engine, which greatly improves the dynamic response of the ammonia engine.

[0027] 4. The motor adopts speed control, which can directly use the speed loop to drag the ammonia fuel engine to idle speed during the start-up phase. During the power output phase, there is no need to switch the control mode, which reduces the control difficulty.

[0028] 5. This invention uses an ammonia fuel engine, which is clean and low-carbon, in line with the development direction of green ships. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the control structure of the present invention;

[0030] Figure 2 This is a hardware structure layout diagram of the present invention. Detailed Implementation

[0031] The invention will now be described in more detail with reference to the accompanying drawings:

[0032] Combination Figure 1-2 This invention discloses a ship hybrid power generation intelligent power generation unit and cooperative control strategy based on a torque observer, including a feedforward ammonia injection dynamic correction lookup table 1, speed regulation ammonia injection MAP lookup table 2, no-load ammonia injection MAP lookup table 3, and smoke limit lookup table 4 in ammonia fuel engine control; speed PID 5; torque observer 6, direct-axis current PID 7, quadrature-axis current PID 8, SVPWM module 9, and inverter 10 in three-phase permanent magnet synchronous motor control.

[0033] In the intelligent power generation unit, the center line of the shaft corresponding to the wide tooth gap of the flywheel signal disk in the ammonia fuel engine is aligned with the spatial position axis of phase A of the stator winding of the three-phase permanent magnet synchronous motor. At the same time, phase A is aligned with the direct axis in both the three-phase coordinate system and the quadrature-direct axis coordinate system. Meanwhile, the crankshaft sensor of the ammonia fuel engine is eliminated.

[0034] The ammonia engine uses throttle torque control, while the three-phase permanent magnet synchronous motor uses speed control.

[0035] The speed control of a three-phase permanent magnet synchronous motor includes using a position sensor to measure the rotor position, using a torque observer to observe the electromagnetic torque (the torque observer is in the form of an extended state observer), and using a dual-loop control of speed and current using a PID loop.

[0036] The expression for the torque observer is:

[0037]

[0038] Where: K active For active flux; L d It is a direct-axis inductor; L q For axial inductance; r req For virtual resistance; i d For stator direct-axis current; i q For stator quadrature-axis current; K E For permanent magnet flux linkage; n is the estimated motor speed. pp J is the number of pole pairs of the motor; s This refers to the moment of inertia of the motor. This is the estimated load torque value; l p ε is the torque observer gain; ε is the error operator;

[0039] The throttle torque control method used in ammonia fuel engines includes: using a smoke limit lookup table with boost pressure, boost temperature, and air flow as inputs; a no-load ammonia injection quantity MAP lookup table with coolant temperature and estimated speed as inputs; a speed-regulating ammonia injection quantity MAP lookup table with pedal position and estimated speed as inputs; and a feedforward ammonia injection quantity dynamic correction lookup table with estimated speed and estimated torque as inputs to comprehensively optimize the ammonia injection quantity and thus control the ammonia engine speed.

[0040] The conversion relationship between the estimated speed of the ammonia fuel engine and the estimated speed of the electric motor is as follows:

[0041]

[0042] Where: n e For ammonia fuel engine speed; θ e θ is the crankshaft rotation angle; r T is the rotor angle of the motor;e For engine torque; η m For motor efficiency.

[0043] The detailed control process is as follows: First, the three-phase current of the three-phase permanent magnet synchronous motor is sampled and converted into the corresponding α and β axis currents in the Clark coordinate system. Using the α and β axis currents as inputs and the motor rotor angle obtained by the position sensor as input, the stator current under the α and β axes is transformed by Park to obtain the stator current under the dq axis. Using the stator current under the dq axis and the motor speed as inputs, the estimated motor speed and estimated load torque are calculated by the torque observer 6 using formulas (1)-(5). The difference between the actual motor speed and the given speed is entered into the speed PID loop 6. The speed PID loop 6 outputs the reference dq axis current and the difference between the actual stator dq axis current fed back by the motor. After passing through the direct axis current PID loop 7 and the quadrature axis current PID loop 8, the given reference voltage under the d and q axes is output. Finally, the SVPWM waveform generation module 9 sends a signal to the inverter 10 to control the motor stator current to control the speed.

[0044] The actual motor speed and estimated motor load torque obtained from motor control are converted into ammonia engine speed and load torque using equation (6). The ammonia engine speed and torque are used as inputs to query the dynamic correction table 1 for feedforward ammonia injection quantity to obtain the feedforward value. The pedal position obtained from the required torque, together with the engine speed, is used as inputs to query the speed-regulating ammonia injection quantity MAP table 2 as the increment. The coolant temperature and engine speed are used as inputs to query the no-load ammonia injection quantity MAP table to obtain the no-load ammonia injection quantity. The boost pressure, boost temperature, and airflow are used as inputs to query the smoke limit as the ammonia injection quantity limit. Finally, the feedforward ammonia injection quantity, speed-regulating ammonia injection quantity, and no-load ammonia injection quantity are accumulated, and the MIN / MAX strategy is used to output the required ammonia injection quantity for the engine, thus completing the engine throttle torque control.

[0045] The crankshaft angle signal required for other engine controls can be given by formula (6) and used to determine the top dead center, cylinder, and fuel injection timing.

Claims

1. A cooperative control method for intelligent power generation units of ship hybrid power generation based on torque observer, characterized by: This includes an ammonia-fueled engine and a three-phase permanent magnet synchronous motor. The ammonia-fueled engine uses throttle torque control, while the three-phase permanent magnet synchronous motor uses speed control. The ammonia-fueled engine uses tables for pre-set smoke limit limits, no-load ammonia injection MAP, speed-regulating ammonia injection MAP, and feedforward ammonia injection dynamic correction. The smoke limit limit lookup uses boost pressure, boost temperature, and airflow as inputs; the no-load ammonia injection MAP uses coolant temperature and estimated speed as inputs; and the speed-regulating ammonia injection MAP uses pedal position and estimated speed as inputs. The feedforward ammonia injection... The ammonia quantity dynamic correction lookup table takes the estimated speed and estimated torque as input, accumulates the feedforward ammonia injection quantity, speed-regulating ammonia injection quantity, and no-load ammonia injection quantity, and uses the smoke limit as a constraint to output the ammonia injection quantity required by the engine using the MIN / MAX strategy, thereby completing the engine throttle torque control and controlling the ammonia engine speed; the center line of the shaft corresponding to the wide tooth gap of the flywheel signal disk in the ammonia fuel engine is aligned with the spatial position axis of phase A of the stator winding of the three-phase permanent magnet synchronous motor, and phase A is aligned with the direct axis in both the three-phase coordinate system and the quadrature-direct axis coordinate system.

2. The method for coordinated control of a ship hybrid power generation intelligent generator unit based on a torque observer according to claim 1, characterized in that: The speed control of a three-phase permanent magnet synchronous motor includes a position sensor, a torque observer, a speed PID loop, and a current PID loop. The position sensor is used to measure the rotor position of the motor, and the torque observer is used to observe the electromagnetic torque. The torque observer adopts the form of an extended state observer. The speed is controlled by a dual-loop PID loop and the current is controlled by a dual-loop PID loop. The torque observer expression is: ； ； ； ； ； in: Active flux; It is a direct-axis inductor; Axial inductance; For virtual resistance; This refers to the stator direct-axis current. This refers to the stator quadrature-axis current; For permanent magnet flux linkage; This is an estimated value for the motor speed; This represents the number of pole pairs of the motor. This refers to the moment of inertia of the motor. This is an estimated value for the load torque; For torque observer gain; This is the error operator.

3. The method for coordinated control of a ship hybrid power intelligent generator unit based on a torque observer according to claim 1, characterized in that: The conversion relationship between the estimated speed of the ammonia fuel engine and the estimated speed of the electric motor is as follows: ； in: This refers to the rotational speed of an ammonia fuel engine. This refers to the crankshaft rotation angle; The angle of the motor rotor; This refers to engine torque; For motor efficiency.

4. The method for coordinated control of a ship hybrid power intelligent generator unit based on a torque observer according to claim 2, characterized in that: The three-phase currents of a three-phase permanent magnet synchronous motor are sampled and converted into their corresponding values ​​in the Clark coordinate system. , shaft current, with , The shaft current is used as the input, and the motor rotor angle sampled by the position sensor is used as the input. , The stator current under the dq axis is obtained by performing the Park transformation on the stator current under the dq axis. Using the stator current and motor speed along the dq axis as inputs, the estimated motor speed and load torque are calculated through the torque observer expression. The difference between the actual motor speed and the given speed is fed into the speed PID loop. The speed PID loop outputs a reference dq axis current, which is then compared with the actual stator dq axis current fed back by the motor. After passing through the direct axis current PID loop and the quadrature axis current PID loop, the output is a reference voltage along the given d and q axes. This voltage is then sent to the inverter via the SVPWM waveform generation module to control the motor stator current and thus control the speed.

5. The method for coordinated control of a ship hybrid power generation unit based on a torque observer according to claim 3, characterized in that: The actual motor speed obtained from motor control and the estimated motor load torque are processed by the formula... The values ​​are converted to ammonia engine speed and load torque. The ammonia engine speed and torque are used as inputs to query the dynamic correction table for feedforward ammonia injection quantity to obtain the feedforward value. The pedal position obtained by the required torque and the engine speed are used as inputs to query the speed regulation ammonia injection quantity MAP table as the increment. The coolant temperature and engine speed are used as inputs to query the no-load ammonia injection quantity MAP table to obtain the no-load ammonia injection quantity. The boost pressure, boost temperature and air flow are used as inputs to query the smoke limit as the ammonia injection quantity limit.

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