A feedback-type onshore multifunctional electronic load system and its control method

Abstract

This invention belongs to the field of land-based integrated commissioning and testing technology for ship power systems. Specifically, it discloses a feedback-type land-based integrated commissioning multifunctional electronic load system and its control method. The system includes a load simulation and feedback main circuit, a detection module, and a control module. The control method includes inputting the desired load power factor; acquiring the system's three-phase power supply and three-phase current, performing coordinate transformation to obtain voltage and current vectors in a two-phase rotating coordinate system; generating target voltage and current vectors in the two-phase rotating coordinate system based on the desired load power factor; comparing the voltage and current vectors, performing PI adjustment, feedforward decoupling, and inverse coordinate transformation; and generating an SVPWM control signal to control the main circuit. This invention can be used as a testing device in an integrated commissioning test field to simulate the load conditions of different ships under different operating conditions, and can also be used as a DC / AC power supply.

Description

Technical Field

[0001] This invention relates to the field of land-based integrated commissioning and testing technology for ship power systems, and particularly to a feedback-type land-based integrated commissioning multifunctional electronic load system and its control method. Background Technology

[0002] As ships develop towards intelligence, integration, and environmental friendliness, the complexity of ship electrical equipment is also increasing. To shorten ship construction cycles, improve the efficiency and success rate of mooring trials, and ensure smooth sea trials, onshore commissioning of ship electrical equipment is of great significance. However, tests often use energy-consuming loads such as water resistance, which consume a large amount of electrical energy as heat. Furthermore, during testing, reactive loads can mostly only be stepped and cannot accurately simulate all operating conditions during ship navigation.

[0003] In the context of promoting "carbon peaking and carbon neutrality," if the electricity generated by the tested units cannot be effectively utilized, the generated energy will be wasted, resulting in a huge waste of resources. Simultaneously, the carbon dioxide and air pollutants produced will affect the air quality of the test site. Furthermore, the power factor of the existing load system composed of water resistors and reactors cannot be precisely adjusted, failing to obtain the equipment status under all operating conditions. Configuring a corresponding load system for each ship and each operating condition would be uneconomical and impractical.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problems existing in the background art. To this end, a feedback-type onshore multifunctional electronic load system and its control method are provided. The multifunctional electronic load system is a multifunctional, modular, low-carbon and environmentally friendly power factor adjustable load. It can be used as a test load for experimental equipment or as an AC / DC power supply. It can smoothly change the power factor of the electronic load by means of the phase and amplitude of voltage and current collected by sensors and adjusted by the control module, thereby increasing the application scenarios of the load. It can also be controlled by the SVPWM signal of the control module to output the required DC and AC voltages for powering other equipment or connecting to the power grid, thereby achieving efficient utilization of electrical energy.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A feedback-type onshore integrated multi-functional electronic load system includes a load simulation and feedback main circuit, a detection module, and a control module;

[0008] The load simulation and feedback main circuit includes an input filter, a load simulation module, a buck-boost chopper module, an inverter module, and an output filter.

[0009] The output terminal of the input filter is electrically connected to the input terminal of the load simulation module, the output terminal of the load simulation module is electrically connected to the input terminal of the buck-boost chopper module, the output terminal of the buck-boost chopper module is electrically connected to the input terminal of the inverter module, and the output terminal of the inverter module is electrically connected to the input terminal of the output filter.

[0010] The detection module includes an input voltage detection module, an input current detection module, and an output voltage and current detection module;

[0011] The input terminal of the input voltage detection module is electrically connected to the input terminal of the input filter; the input terminal of the input current detection module is electrically connected to the output terminal of the input filter and the output terminal of the input voltage detection module; and the input terminal of the output voltage and current detection module is electrically connected to the output terminal of the output filter.

[0012] The output terminals of the input voltage detection module, the input current detection module, and the output voltage and current detection module are all electrically connected to the control module.

[0013] The load simulation module, buck-boost chopper module, and inverter module are all electrically connected to the control module.

[0014] The following is a further technical solution for the system in this invention: the input end of the input filter is connected to a three-phase power supply.

[0015] The following is a further defined technical solution for the system in this invention: the load simulation module is configured as a three-phase full-bridge rectifier circuit, and the inverter module is configured as a three-phase full-bridge inverter circuit.

[0016] A control method for an electronic load system based on the above-mentioned feedback-type onshore multifunctional electronic load system includes the following steps:

[0017] Step S1: Input the desired load power factor;

[0018] Step S2: Collect the three-phase power supply and three-phase current of the system;

[0019] Step S3: Perform coordinate transformation on the voltage and current collected in step S2 to obtain the voltage and current vectors in a two-phase rotating coordinate system;

[0020] Step S4: Generate the target voltage and current vectors in a two-phase rotating coordinate system based on the load power factor expected in step S1;

[0021] Step S5: Compare the voltage and current vectors from Step S3 and Step S4;

[0022] Step S6: Adjust the comparison results obtained in step S5 using PI.

[0023] Step S7: Perform feedforward decoupling based on the adjustment parameters obtained in step S6;

[0024] Step S8: Perform an inverse coordinate transformation on the voltage parameters obtained from the decoupling in step S7;

[0025] Step S9: Generate SVPWM control signal;

[0026] Step S10: Output control signal to control the main circuit to work.

[0027] The following is a further technical solution for the method of the present invention: in step S1, the input desired load power factor is a continuously changing power factor.

[0028] The following is a further technical solution for the method of the present invention: the three-phase current collected in step S2 is the three-phase current after harmonic elimination.

[0029] The following is a further technical solution for the method of the present invention: the three-phase voltage collected in step S2 is passed through a phase-locked loop.

[0030] The following is a further technical solution for the method of the present invention: the coordinate system transformation in step S3 includes the transformation between three-phase coordinates and two-phase coordinates and the transformation between stationary coordinates and rotating coordinates.

[0031] The following is a further technical solution for the method of the present invention: the inverse coordinate transformation in step S8 includes the transformation between rotating coordinates and stationary coordinates and the transformation between two-phase coordinates and three-phase coordinates.

[0032] The following is a further technical solution that defines the method in this invention: the SVPWM control signal generated in step S9 is directly applied to the load simulation module.

[0033] Compared with the prior art, the present invention has the following technical effects:

[0034] The multifunctional electronic load system of this invention can be used as a testing device in a test field, and also as a DC and AC power source. When used as a testing device, it can continuously adjust the power factor to simulate the load conditions of different ships under different operating conditions. It can also feed the detected electrical energy back to the power grid in the test field to improve energy utilization efficiency and reduce energy loss, thereby achieving the goals of energy conservation, emission reduction, and low-carbon environmental protection. When used as a power source, it can output DC and AC power and adjust the voltage level according to actual needs.

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a system connection block diagram of the present invention;

[0038] Figure 2 This is a topology diagram of the system main circuit structure of the present invention;

[0039] Figure 3 This is a flowchart of the method of the present invention. Detailed Implementation

[0040] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0041] like Figure 1-3 As shown, this embodiment provides a feedback-type onshore integrated multi-functional electronic load system (also known as a shore power system) and a control method for the feedback-type onshore integrated multi-functional electronic load system.

[0042] like Figure 1 and 2 As shown, a regenerative onshore multifunctional electronic load system comprises a load simulation and feedback main circuit, a detection module, and a control module. The main circuit adopts a back-to-back topology with input and output filters, specifically including an input filter, a load simulation module, a buck-boost chopper module, an inverter module, and an output filter.

[0043] The load simulation and feedback main circuit, starting from the input, passes through an input filter, a load simulation module, and a buck-boost chopper module to obtain DC power at a specified voltage level. After the buck-boost chopper module, it is fed back to the field power grid via an inverter module and an output filter. The detection module includes input voltage detection, input current detection, and output voltage and current detection modules. Its function is to collect the voltage and current at each node in the load simulation and feedback main circuit and transmit the collected data to the control module. The control module includes a power factor control module and a voltage control module. It receives signals from the load simulation and feedback main circuit and the detection module, and then transmits control signals to the load simulation module, buck-boost chopper module, and inverter module to adjust the power factor and voltage level of the multifunctional electronic load system. The control module controls the operation of the entire system.

[0044] The system inputs the desired power factor and DC voltage; detects the input voltage, sends the acquired voltage to the control module, and filters the input current; detects the input current, sends the acquired current to the control module; the control module outputs a control signal to the load simulation module based on the desired power factor, while simultaneously detecting the voltage and current of the load simulation module; the control module outputs a control signal to the buck-boost chopper module based on the desired DC voltage and outputs DC current, while simultaneously detecting the voltage and current of the buck-boost chopper module; it acquires the voltage and current of the power grid in the field area and sends them to the control module; the control module sends a control signal to the inverter module based on the grid connection conditions, while simultaneously detecting the voltage and current of the inverter module; the inverted current passes through the output filter and is connected to the power grid in the field area.

[0045] The three-phase power supply on the input side is connected to the input filter. The input filter consists of three capacitors C1 and three inductors L1. The three capacitors C1 are connected in a delta configuration. The delta capacitor structure is connected to the three-phase power supply. The three-phase outputs of the three-phase power supply are each connected to the load simulation module (also known as the load simulation circuit) through an inductor L1.

[0046] The load simulation circuit is configured as a three-phase full-bridge PWM rectifier circuit composed of six MOSFETs. The three-phase output terminals of the input filter are connected to two MOSFETs respectively. Specifically, the source of one MOSFET (MOSFET 1) and the drain of another MOSFET (MOSFET 2) are both connected to one output terminal of the input filter. At the same time, the drain of MOSFET 1 is connected to the positive terminal of the DC bus, and the source of MOSFET 2 is connected to the negative terminal of the DC bus.

[0047] A buck-boost chopper module (also known as a buck-boost chopper circuit) is connected between the positive and negative terminals of the DC bus.

[0048] The buck-boost chopper circuit consists of two capacitors, one unidirectional diode, one inductor, and one MOSFET. One capacitor, Cin, serves as the input capacitor of the buck-boost chopper circuit, connected between the positive and negative terminals of the DC bus for detecting the DC input voltage. The other capacitor, Cout, serves as the output capacitor of the buck-boost chopper circuit, connected between the positive and negative terminals of the DC bus for detecting the DC output voltage. The inductor is connected between the positive and negative terminals of the DC bus. Both the unidirectional diode and the MOSFET are located on the positive terminal of the DC bus.

[0049] The two ends of the output capacitor Cout are connected to the inverter module (also known as the inverter circuit).

[0050] The inverter circuit consists of six MOSFETs and has three-phase outputs. Each of the three-phase outputs is connected to two MOSFETs. Specifically, the source of one MOSFET (MOSFET three) and the drain of another MOSFET (MOSFET four) are both connected to one output of the inverter circuit. Simultaneously, the drain of MOSFET three is connected to the positive terminal of the DC bus, and the source of MOSFET four is connected to the negative terminal of the DC bus.

[0051] The three-phase output terminals of the inverter circuit are connected to an output filter. The output filter consists of three capacitors C2 and three inductors L2. The three capacitors C2 are connected in a delta configuration. The three-phase output terminals of the inverter circuit are each connected to the delta capacitor structure through an inductor L2. The output filter outputs three-phase AC power.

[0052] like Figure 2 As shown, the detection module detects the input voltage of the input filter (i.e., the output voltage of the three-phase power supply), the input current of the load simulation circuit (i.e., the output current of the input filter), the output voltage of the load simulation circuit (i.e., the DC side input voltage), and the output voltage of the buck-boost chopper circuit (i.e., the DC side output voltage).

[0053] In summary, the load simulation and feedback main circuit is divided into three parts. The front-end circuit is mainly responsible for preprocessing the test power supply and simulating the load. After passing through the input filter, it is then regulated by the control module, using a PWM rectifier circuit to simulate loads with different power factors to test the performance of the test power supply. The middle part is a buck-boost chopper circuit, which is a DC power supply with variable voltage levels. The control module ensures accurate voltage conversion to meet the requirements of different voltage levels during the test. The rear-end circuit is an inverter circuit, whose main function is to invert the chopped DC power into grid-connected AC power, which is then connected to the field power grid to achieve energy feedback and improve energy utilization efficiency.

[0054] A control method for an electronic load system based on the above-mentioned feedback-type onshore multifunctional electronic load system specifically includes the following steps:

[0055] Step S1: Input the desired load power factor (controlled by the power factor control module) and DC voltage (controlled by the voltage control module). The input desired load power factor is a continuously varying power factor.

[0056] Step S2: Collect the three-phase power supply voltage and three-phase current information of the system, send the collected information data to the control module, and filter the three-phase input current. Therefore, the collected three-phase current is the three-phase current after harmonic elimination, and the collected three-phase voltage is passed through a phase-locked loop.

[0057] Step S3: Perform coordinate system transformation on the voltage and current acquired in step S2 to obtain the voltage and current vectors in a two-phase rotating coordinate system. The coordinate system transformation includes the transformation between three-phase coordinates and two-phase coordinates, and the transformation between stationary coordinates and rotating coordinates.

[0058] Step S4: Generate the target voltage and current vectors in a two-phase rotating coordinate system based on the load power factor expected in step S1.

[0059] Step S5: Compare the voltage and current vectors from Step S3 and Step S4, and calculate the deviations of the reactive and active components respectively.

[0060] Step S6: Adjust the comparison results obtained in step S5 using PI.

[0061] Step S7: Perform feedforward decoupling based on the adjustment parameters obtained in step S6.

[0062] Step S8: Perform an inverse coordinate transformation on the voltage parameters obtained from the decoupling in step S7 to obtain the voltage vector in a three-phase rotating coordinate system. The inverse coordinate transformation includes the transformation between rotating coordinates and stationary coordinates, and the transformation between two-phase coordinates and three-phase coordinates.

[0063] Step S9: Generate the desired load power factor (SVPWM) control signal for the electronic load system. The generated SVPWM control signal is directly applied to the load simulation module.

[0064] Step 10: The control module outputs an SVPWM control signal to control the load simulation module in the main circuit to work.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and modifications to the technical solution of the present invention, or modify it into equivalent embodiments, without departing from the scope of the present invention's technical solution. Therefore, all equivalent changes made based on the shape, structure, and principle of the present invention without departing from the scope of the present invention's technical solution should be covered within the protection scope of the present invention.

Claims

1. A feedback-type onshore multi-functional electronic load system, characterized in that, Includes a load simulation and feedback main circuit, a detection module, and a control module; The load simulation and feedback main circuit includes an input filter, a load simulation module, a buck-boost chopper module, an inverter module, and an output filter. The output terminal of the input filter is electrically connected to the input terminal of the load simulation module, the output terminal of the load simulation module is electrically connected to the input terminal of the buck-boost chopper module, the output terminal of the buck-boost chopper module is electrically connected to the input terminal of the inverter module, and the output terminal of the inverter module is electrically connected to the input terminal of the output filter. The detection module includes an input voltage detection module, an input current detection module, and an output voltage and current detection module; The input terminal of the input voltage detection module is electrically connected to the input terminal of the input filter; the input terminal of the input current detection module is electrically connected to the output terminal of the input filter and the output terminal of the input voltage detection module; and the input terminal of the output voltage and current detection module is electrically connected to the output terminal of the output filter. The output terminals of the input voltage detection module, the input current detection module, and the output voltage and current detection module are all electrically connected to the control module. The load simulation module, buck-boost chopper module, and inverter module are all electrically connected to the control module. The load simulation and feedback main circuit starts from the input, passes through the input filter, load simulation module, and buck-boost chopper module, and obtains DC power at the specified voltage level. After the buck-boost chopper module, it is fed back to the field power grid through the inverter module and output filter. The detection module collects the voltage and current of each node in the load simulation and feedback main circuit and transmits the collected information data to the control module. The control module receives the signals from the load simulation and feedback main circuit and the detection module, and then transmits the control signals to the load simulation module, buck-boost chopper module, and inverter module to adjust the power factor and voltage level of the multifunctional electronic load system. Input the desired power factor and DC voltage; The system detects the input voltage and sends the acquired voltage to the control module, while also filtering the input current. It detects the input current and sends the acquired current to the control module. Based on the desired power factor, the control module outputs a control signal to the load simulation module, while simultaneously detecting the voltage and current of the load simulation module. Based on the desired DC voltage, the control module outputs a control signal to the buck-boost chopper module and outputs DC power, while simultaneously detecting the voltage and current of the buck-boost chopper module. It also collects the voltage and current of the power grid in the site area and sends them to the control module. Based on the grid connection conditions, the control module sends a control signal to the inverter module, while simultaneously detecting the voltage and current of the inverter module. The inverted current passes through an output filter and is then connected to the power grid in the site area.

2. The feedback-type onshore multi-functional electronic load system as described in claim 1, characterized in that, The input terminal of the input filter is connected to a three-phase power supply.

3. The feedback-type onshore multi-functional electronic load system as described in claim 1, characterized in that, The load simulation module is configured as a three-phase full-bridge rectifier circuit, and the inverter module is configured as a three-phase full-bridge inverter circuit.

4. A control method for an electronic load system based on the feedback-type onshore multifunctional electronic load system according to any one of claims 1-3, characterized in that, Includes the following steps: Step S1: Input the desired load power factor; Step S2: Collect the three-phase power supply and three-phase current of the system; Step S3: Perform coordinate transformation on the voltage and current collected in step S2 to obtain the voltage and current vectors in a two-phase rotating coordinate system; Step S4: Generate the target voltage and current vectors in a two-phase rotating coordinate system based on the load power factor expected in step S1; Step S5: Compare the voltage and current vectors from Step S3 and Step S4; Step S6: Adjust the comparison results obtained in step S5 using PI. Step S7: Perform feedforward decoupling based on the adjustment parameters obtained in step S6; Step S8: Perform an inverse coordinate transformation on the voltage parameters obtained from the decoupling in step S7; Step S9: Generate SVPWM control signal; Step S10: Output control signal to control the main circuit to work.

5. The electronic load system control method as described in claim 4, characterized in that, In step S1, the desired load power factor is input as a continuously varying power factor.

6. The electronic load system control method as described in claim 4, characterized in that, The three-phase current collected in step S2 is the three-phase current after harmonic elimination.

7. The electronic load system control method as described in claim 4, characterized in that, The three-phase voltages collected in step S2 are processed by a phase-locked loop.

8. The electronic load system control method as described in claim 4, characterized in that, The coordinate system transformation in step S3 includes the transformation between three-phase coordinates and two-phase coordinates, and the transformation between stationary coordinates and rotating coordinates.

9. The electronic load system control method as described in claim 4, characterized in that, The inverse coordinate transformation in step S8 includes the transformation between rotating coordinates and stationary coordinates, and the transformation between two-phase coordinates and three-phase coordinates.

10. The electronic load system control method as described in claim 4, characterized in that, The SVPWM control signal generated in step S9 is directly applied to the load simulation module.

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