Method for simulating operating parameters of a large generator

Abstract

The application provides a method for simulating operation parameters of a large generator, and belongs to the technical field of generator set testing. In the engine water power dynamometer test environment, a small generator is installed on the free end of the engine, the small generator generates a simulated electric energy signal during engine operation and delivers the simulated electric energy signal to an ECU control unit; the ECU control unit controls a contactor to simulate closing according to the voltage and frequency signals, so that current flows through a three-phase voltage regulator and a load unit; at the same time, a PLC load control unit receives a power signal of the water power dynamometer and an electric power signal fed back by the ECU, calculates a deviation through a PID algorithm, and outputs a pulse signal to drive the three-phase voltage regulator to adjust the load current, so as to form a closed-loop control system. The application simulates the electric energy output of a real generator in a water power dynamometer test environment in a low-cost manner, so that the engine control system can obtain complete electric energy parameters, early verification of the generator set control system is realized, the modification cost is low, and the product research and development cycle is significantly shortened.

Description

Technical Field

[0001] This invention belongs to the field of generator set testing technology, specifically relating to a method for simulating the operating parameters of a large generator. It is particularly suitable for use in engine hydraulic dynamometer testing environments, where a small generator simulates the electrical energy output of a real large generator, providing complete electrical energy parameters for the generator set control system and enabling closed-loop control function verification. Background Technology

[0002] Before leaving the factory, large generator sets typically undergo a series of steady-state and transient tests, including break-in tests, performance adjustment tests, and type tests, to verify whether the engine meets the factory performance requirements.

[0003] Single-unit engine testing typically uses a hydraulic dynamometer as the load. When used as a generator set, it is usually tested and debugged with a matching generator. However, in this method, the power output of the hydraulic dynamometer cannot output the motor's electrical energy signal as a generator set. Consequently, the generator set's control system cannot acquire the generator's electrical parameters during the test, preventing the formation of a complete closed-loop control system. This method of using a hydraulic dynamometer as the load clearly cannot meet the performance testing requirements of generator sets.

[0004] During the development of generator sets, using a hydraulic dynamometer as a load allows for single-unit engine testing, but it cannot verify the overall performance of the generator set and control system. Previously, generator set testing required the connection of the entire assembly, including the engine, generator, and common base, and the electrical load system also had to meet testing requirements. Modifying the test bench, especially the electrical load system, was a lengthy and costly process.

[0005] This necessitates repeating unit performance tests after individual engine tests, and the relevant parameters of the control system must be readjusted based on the generator's electrical energy signals during the test, further increasing testing costs. Therefore, it is difficult to standardize the debugging parameters for large engine individual engine tests and unit tests, requiring repeated steady-state and transient performance debugging tests. Summary of the Invention

[0006] The technical problem solved by this invention is to provide a method for simulating the operating parameters of a large generator. The purpose of this invention is to design a complete closed-loop system that can accurately simulate the electrical energy parameters of a generator set under various operating conditions in a hydraulic dynamometer test environment, providing robust test conditions for generator set performance testing and control system function verification. This system can be implemented at low cost, enabling the engine hydraulic dynamometer test environment and the engine control system in the generator set test environment to receive the same electrical energy signals, greatly simplifying the test procedures for generator set commissioning and saving commissioning time and costs.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for simulating the operating parameters of a large generator, used to simulate the operating conditions of a generator set in an engine hydraulic dynamometer test environment, includes: installing a small generator at the free end of the engine, the small generator generating simulated electrical energy signals as the engine operates; transmitting the simulated electrical energy signals to the engine ECU control unit; the ECU control unit adjusting the current of the load unit by controlling a three-phase voltage regulator according to the received simulated electrical energy signals, forming a closed-loop control system for simulating generator operation.

[0008] Furthermore, it also includes a load control unit mainly based on a PLC; the load control unit receives the engine power signal detected by the hydraulic dynamometer and the electrical power signal fed back by the ECU control unit; the load control unit calculates the control pulse through the PID algorithm, and drives the servo mechanism of the three-phase voltage regulator after processing by the pulse generator and the stepper motor driver, thereby adjusting the terminal voltage of the load unit and forming a closed-loop servo control system with power deviation as input and pulse signal as output.

[0009] Regarding the detection of electrical parameters, the simulated electrical signal includes voltage and frequency signals; the ECU control unit monitors the three-phase voltage of the small generator through the voltage terminals Ua, Ub, and Uc, and obtains the generator frequency by analyzing the three-phase voltage signal, thereby calculating the engine speed and power.

[0010] Regarding the closing simulation, an M contactor is installed between the ECU control unit, the three-phase voltage regulator, and the load unit to simulate the closing and opening operations of the generator output switchgear. The ECU control unit monitors the voltage and frequency signals output by the small generator to determine whether the generator meets the closing conditions and controls the M contactor to close, simulating the closing operation of the generator output switchgear. When the ECU control unit detects that the voltage and frequency are normal, it issues a closing command, and the M contactor closes. After the M contactor closes, the current output by the small generator flows sequentially through the I1, I2, and I3 current detection terminals of the ECU control unit, the three-phase voltage regulator, and the load unit, forming a power circuit.

[0011] To ensure system safety, a thermal-magnetic circuit breaker is connected in series between the output terminal of the three-phase voltage regulator and the load unit, which is used to automatically disconnect the load circuit in the event of overcurrent, protecting the ECU control unit and the three-phase voltage regulator.

[0012] In terms of closed-loop control, the ECU control unit transmits the detected power signal to the load control unit in real time via communication. The load control unit compares the received power signal with the power signal detected by the hydraulic dynamometer to form a deviation signal, which serves as the input to the PID algorithm. Based on the calculated pre-output, the load control unit continuously feeds back the power signal detected by the ECU to the load control unit, compares it with the existing adjustment signal, and calculates the "output" to drive the stepper motor based on this error, thereby achieving precise control of the voltage regulator's output current and outputting a more accurate adjustment signal.

[0013] Regarding the installation method of the small generator, the present invention adopts the following structure: the small generator is mounted on the free end camshaft of the engine; a camshaft shock absorber and a shock absorber transition flange are connected in sequence on the camshaft; the shock absorber transition flange is connected to the drive shaft of the small generator through an elastic coupling, which is used to absorb vibration and compensate for axial misalignment.

[0014] Preferably, the flexible coupling is a three-jaw flexible coupling.

[0015] Working principle: During engine operation, the camshaft shaft rotates, driving a small generator connected to the shaft to generate electricity and send a voltage signal to the ECU control unit. At the same time, the control unit also detects a frequency signal from the voltage signal. At this time, the generator is running at its rated speed under no-load conditions.

[0016] When the ECU control unit detects that the generator voltage and frequency are normal, it issues a switch cabinet closing command, the M contactor is energized, and at the same time, the switch closing status is fed back to the engine ECU control unit, and the generator set is in a load-bearing operation state.

[0017] After the M contactor is engaged, the generator output current enters the three-phase voltage regulator through the current detection terminal of the engine ECU control unit. The PLC control system controls the output voltage of the three-phase voltage regulator, thereby adjusting the terminal voltage of the three-phase load resistor to control the current flowing through the three-phase load.

[0018] The ECU control unit can determine the magnitude of the generator's three-phase current by monitoring the current at the current detection terminal; by monitoring the voltage terminal, it can monitor the generator's three-phase voltage and simultaneously analyze the generator frequency signal, thereby indirectly calculating a series of electrical energy parameters such as engine speed and engine power.

[0019] When the engine is running under load, the hydraulic dynamometer transmits the engine operating power signal to the PLC control unit. The control unit combines the received power signal with the real-time power feedback from the ECU control unit and converts it into a pulse signal for the three-phase voltage regulator servo controller, forming a complete PID closed-loop servo control system that ensures output accuracy while taking into account the transient changes in engine load.

[0020] Advantages of this invention compared to existing technologies: 1. The design concept of this scheme is unique and novel: it adopts a simulation approach that achieves great results with minimal investment, and perfectly combines mechanical energy, electrical energy, power electrical systems and automatic control. Without changing the original hydraulic dynamometer test environment, it realizes the complete performance verification of the generator set. 2. This solution has high control precision: It adopts a PID algorithm to form a closed-loop servo control system, which can accurately simulate the electrical energy parameters of the generator under various operating conditions and meet the requirements of steady-state and transient tests. 3. This solution is low-cost and quick to take effect: Taking a 4000KW generator set as an example, the modification of the traditional generator and test bench load system would require at least 3 million yuan, while the installation cost of this system is only about 30,000 yuan, and it fully meets the test requirements; 4. This solution shortens the R&D cycle: It saves time on the design, production, and load modification of the generator set's common base and test bench, avoids the repetitive work of retesting the unit's performance after single-unit testing, and significantly shortens the new product development cycle; 5. Wide applicability: This invention provides a design concept for generator simulation testing, which can be applied to various fields that require simulation of generator operating parameters, and has strong versatility and promotional value. Attached Figure Description

[0021] Figure 1 This is a diagram of the overall system architecture of the present invention; Figure 2 This is a schematic diagram of the logic signal transmission of the control system of the present invention; Figure 3 This is a schematic diagram of the motor installation position according to the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please see Figure 1-3 The embodiments of the present invention are described in detail below.

[0024] Example 1: System Overall Architecture like Figure 1 As shown, the system of this invention mainly consists of an engine 1, a hydraulic dynamometer 2, a small generator 3, an ECU control unit 4, a three-phase voltage regulator 5, a load unit 6, and a load control unit 7 mainly based on a PLC. It also includes a signal feedback unit and a safety unit.

[0025] The main output shaft of engine 1 is connected to a hydraulic dynamometer 2 to consume the mechanical power output by the engine. A small generator 3 is connected to the free end camshaft 1-1 of engine 1 to generate analog electrical signals.

[0026] The power output terminal of the small generator 3 is connected to the voltage detection terminal and the input terminal of the M contactor of the ECU control unit 4. The output terminal of the M contactor is connected to the current detection terminal of the ECU control unit 4, and then connected in sequence to the three-phase voltage regulator 5 and the load unit 6.

[0027] The power signal output of the hydraulic dynamometer 2 is connected to the load control unit 7. The communication port of the ECU control unit 4 is connected to the load control unit 7. The control output of the load control unit 7 is connected to the servo drive mechanism of the three-phase voltage regulator 5 through the pulse generator 8 and the stepper motor driver 9.

[0028] Example 2: Installation method of small generator like Figure 3 As shown, the small generator 3 is mounted on the camshaft at the free end of the engine. The specific installation method is as follows: first, connect the shock absorber transition flange 1-3 to the camshaft shock absorber 1-2, and then use a three-jaw flexible coupling 1-4 to connect the shock absorber transition flange 1-3 to the drive shaft of the small generator 3.

[0029] This installation method has the following advantages: First, it absorbs the vibration transmitted from the engine to the camshaft through the flexible coupling, protecting the small generator; second, it solves the problem of misalignment between the output shaft of the camshaft damper transition flange and the generator drive shaft, making installation convenient and achieving good results. Example 3: Control Process

[0030] After the engine starts, the camshaft drives the small generator to rotate, and the small generator generates three-phase AC power. The ECU control unit 4 monitors the voltage through terminals Ua, Ub, and Uc. When the voltage and frequency reach normal values, it issues a closing command, and the M contactor engages.

[0031] After the M contactor is engaged, current flows through the I1, I2, and I3 current detection terminals of the ECU control unit 4 and enters the three-phase voltage regulator 5. The load control unit 7 sends control pulses to the three-phase voltage regulator 5 according to the preset test conditions to adjust its output voltage, thereby controlling the current flowing through the load unit 6.

[0032] The ECU control unit 4 calculates the electrical power in real time based on the detected voltage and current, and sends the power value to the load control unit 7 via communication. At the same time, the hydraulic dynamometer 2 sends the mechanical power output by the engine to the load control unit 7.

[0033] The load control unit 7 compares the two received power values ​​and calculates the deviation. For example... Figure 2 As shown, the load control unit 7 uses a PID algorithm to continuously feed back the power signal detected by the ECU to the load control unit based on the calculation of the pre-output. It compares the power signal detected by the hydraulic dynamometer with the power signal detected by the hydraulic dynamometer, and calculates the output value of the stepper motor based on this error, thereby achieving precise control of the output current of the voltage regulator. Example 4: Safety Protection

[0034] In the power circuit, a thermal-magnetic circuit breaker is installed at the output terminal of the three-phase voltage regulator 5. When an overcurrent occurs due to an abnormal condition in the load or voltage regulator, the thermal-magnetic circuit breaker will promptly disconnect the load circuit, thereby effectively protecting the voltage regulator and load resistor, and preventing the high-value ECU controller from burning out.

[0035] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0036] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for simulating the operating parameters of a large generator, used to simulate the operating conditions of a generator set in an engine hydraulic dynamometer test environment, characterized in that: include: A small generator (3) is installed at the free end of the engine (1), and the small generator (3) generates analog electrical signals as the engine (1) operates. The simulated electrical energy signal is transmitted to the engine ECU control unit (4); the ECU control unit (4) adjusts the current of the load unit (6) by controlling the three-phase voltage regulator (5) according to the received simulated electrical energy signal, forming a closed-loop control system for simulating generator operation.

2. The method for simulating the operating parameters of a large generator according to claim 1, characterized in that: It also includes a load control unit (7) mainly based on PLC; The load control unit (7) receives the engine power signal detected by the hydraulic dynamometer (2) and the electrical power signal fed back by the ECU control unit (4); The load control unit (7) calculates the control pulse through the PID algorithm, and drives the servo mechanism of the three-phase voltage regulator (5) after processing by the pulse generator (8) and the stepper motor driver (9), thereby adjusting the terminal voltage of the load unit (6) and forming a closed-loop servo control system with power deviation as input and pulse signal as output.

3. The method for simulating the operating parameters of a large generator according to claim 1, characterized in that: The analog electrical energy signal includes a voltage signal and a frequency signal; The ECU control unit (4) monitors the three-phase voltage of the small generator (3) through the voltage terminals Ua, Ub, and Uc, and obtains the generator frequency by analyzing the three-phase voltage signal, thereby calculating the engine speed and power.

4. The method for simulating the operating parameters of a large generator according to claim 3, characterized in that: An M contactor is provided between the ECU control unit (4), the three-phase voltage regulator (5), and the load unit (6) to simulate the closing and opening operations of the generator output switch cabinet; The ECU control unit (4) monitors the voltage and frequency signals output by the small generator (3) to determine whether the generator has the conditions for closing, and controls the M contactor to close, simulating the closing operation of the generator output switch cabinet. When the ECU control unit (4) detects that the voltage and frequency are normal, it issues a closing command, and the M contactor is energized; After the M contactor is engaged, the current output by the small generator (3) flows sequentially through the I1, I2, and I3 current detection terminals of the ECU control unit (4), the three-phase voltage regulator (5), and the load unit (6) to form a power circuit.

5. The method for simulating the operating parameters of a large generator according to claim 1, characterized in that: A thermal-magnetic circuit breaker is connected in series between the output end of the three-phase voltage regulator (5) and the load unit (6) to automatically disconnect the load circuit when an overcurrent occurs, thereby protecting the ECU control unit (4) and the three-phase voltage regulator (5).

6. The method for simulating the operating parameters of a large generator according to claim 2, characterized in that: The ECU control unit (4) transmits the detected power signal to the load control unit (7) in real time via communication. The load control unit (7) compares the received power signal with the power signal detected by the hydraulic dynamometer (2) to form a deviation signal, which is used as the input of the PID algorithm.

7. The method for simulating the operating parameters of a large generator according to claim 1, characterized in that: The small generator (3) is mounted on the free end camshaft (1-1) of the engine (1); the camshaft (1-1) is connected in sequence to a camshaft damper (1-2) and a damper transition flange (1-3); the damper transition flange (1-3) is connected to the drive shaft of the small generator (3) through a flexible coupling (1-4) to absorb vibration and compensate for axial misalignment.

8. The method for simulating the operating parameters of a large generator according to claim 7, characterized in that: The flexible coupling (1-4) is a three-jaw flexible coupling.

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