WO2022028066A1

WO2022028066A1 - Rapid current amplification system and method based on power amplifier

Info

Publication number: WO2022028066A1
Application number: PCT/CN2021/096787
Authority: WO
Inventors: 许守东; 邹京希; 李胜男; 李波; 陈勇; 朱全聪; 张丽; 周鑫; 奚鑫泽; 邢超; 彭俊臻; 卢佳
Original assignee: 云南电网有限责任公司电力科学研究院
Priority date: 2020-08-06
Filing date: 2021-05-28
Publication date: 2022-02-10
Also published as: JP2023512348A; JP7385184B2; CN111896907A; CN111896907B

Abstract

A rapid current amplification system and method based on a power amplifier. The system comprises a main power module, a main control module, and rapid current amplification modules. The main power module is connected to the main control module. Several rapid current amplification modules are connected in parallel and connected to the main power module. Each group of rapid current amplification modules comprises two signal analysis processing modules and a load. The two signal analysis processing modules are connected in parallel. The input ends of the signal analysis processing modules are connected to the main power module, and the output ends are connected to the load. The operating state of the load is determined, and the switching frequency of the current is changed, so that the current output of the current amplifier is maintained at a peak value. The system has the advantages of improving the power factor by changing the current amplification mode, i.e., amplifying fundamental current by means of a power amplifier. Using multiple 5-10 KW power modules connected in parallel as the main power module improves the stability of the power supply. In addition, a low-power power supply has a relatively high switching frequency, thereby providing a sufficient inductive load on the current transformer.

Description

A system and method for rapid current amplification based on power amplifier

technical field

The present application relates to a circuit rapid amplification technology in a test circuit, and in particular, to a power amplifier-based current rapid amplification system and method.

Background technique

Relay protection is the main technical measure to ensure the safe and stable operation of the power system. The protection effect is affected by the current transformers that provide current information in the power system, especially the transient characteristics of the current transformers. The poor transient characteristics of the current transformer will cause malfunction and refusal of the relay protection, threatening the safe and stable operation of the power system. Therefore, it is necessary to test or test the performance of the current transformers connected to the power system.

Testing and testing current transformers requires test equipment that can respond quickly and output large currents. At present, the test and detection of current transformers are carried out by selecting high-power power supplies, and using power frequency transformers to perform step-down isolation processing on the high-power power supplies to ensure the smooth generation of large currents that can be connected to the test equipment.

However, using the above method to test, the resulting power factor is low. In addition, the switching frequency of the high-power power supply is low, the inductive load on the current transformer cannot form a sufficient load voltage, and the actual current cannot meet the test requirements.

Application content

In order for the test equipment to provide fast response and output large current in the current transformer test and detection, the purpose of the present application is to provide a power amplifier-based current rapid amplification system and method thereof.

Based on the above purpose, the power amplifier-based current rapid amplification system of the present application includes a main power supply module, a main control module and a current rapid amplification module, wherein the main power supply module is connected to the main control module, and several current rapid amplification modules are connected in parallel, Connected to the main power module, the current fast amplification module includes two signal analysis and processing modules and a load, the two signal analysis modules are connected in parallel, the input end of the signal analysis module is connected to the main power module, and the output end is connected to the same load;

The signal analysis module includes a control switch, a filter, a high-bandwidth DA converter, a power amplifier and a high-speed current sensor connected in sequence, the control switch is connected to the main power module, and the high-speed current sensor is connected to the load;

The control switch, the high-speed current sensor and the load are all connected with the main control module through a feedback circuit;

The main control module is configured to perform the following steps:

Set the value of the maximum current and input it into the control module, and calculate the maximum inductance of the load through the maximum current;

According to the duty cycle of the control switch, determine the output filter inductance, and set the current switching frequency of the main power module;

Set the filter mode of the filter, set the filter mode of one filter in the same current fast amplification module to harmonic current, and set the filter mode of the other filter to transient current;

Receive the inductive current value fed back by the high-speed current sensor and the load inductance fed back by the load, and calculate the actual output inductance;

According to the maximum output inductance of the load, the working state of the load is judged, and the switching frequency of the current is changed, so that the current output of the current amplifier is maintained at the peak value.

In order to improve the efficiency of current amplification, the power amplifiers in the two parallel signal analysis modules are respectively a full-bridge switching amplifier and a full-bridge linear amplifier.

Optionally, the load is a current transformer, and the control end of the current transformer is connected to a control module.

Optionally, the main power module is composed of several power supplies with a voltage of 5-10KW in parallel.

The method for rapidly generating a large current in the present application, implemented by a power amplifier-based rapid current amplification system, includes the following steps:

Selecting several groups of independent current rapid amplification modules, and uniformly controlling the control switches of the current rapid amplification modules through the control module;

The current of the power module passes through the filter of the parallel signal analysis module respectively, and the filter selects the harmonic current and the transient current respectively;

Determine the maximum inductance of the load according to the maximum current, and determine the output filter inductance according to the duty cycle of the switching operation, set the switching frequency of the current, and control the output current of the main power module;

The filtered transient current and harmonic current are respectively sampled by the parallel high-speed DA converter, and the current is amplified by the power amplifier. The over-amplified transient current is used as the transient current signal in the initial stage and is input to the current mutual inductance. in the device;

The harmonic current is amplified by the power amplifier, and after the current is amplified to the peak value, the transient current output is completed, the control switch is cut off, the output of the transient current is stopped, and the harmonic current signal is continuously output;

The high-speed current sensor senses the amplified harmonic current and feeds it back to the control module through the feedback circuit; at the same time, the induced current in the current transformer is fed back to the control module through the feedback circuit;

The main control module monitors the harmonic current status in real time according to the received harmonic current and induced current;

Monitored that the harmonic current is not at the peak value, the main control module compares the maximum output inductance of the current transformer according to the actual output inductance of the induced current current transformer, judges the working state of the current transformer, changes the current frequency, and makes the current amplifier reach the current output peak.

In order to improve the current amplification effect, the harmonic current is amplified by a full-bridge switching amplifier, and the transient signal is amplified by a full-bridge linear amplifier.

In this application, the method for judging the working state of the current transformer: calculate the maximum filter inductance of the current transformer, and compare it with the actual output filter inductance of the feedback current transformer to judge the working state of the current transformer.

Optionally, the output filter inductance of the current transformer is

Among them: U is the maximum voltage of the load, s is the current rise time, and I is the maximum current.

Optionally, the inductive reactance of the output load is determined according to the maximum inductance of the output load, the maximum load voltage and the switching duty cycle.

In this application, the current amplification method is changed, and the fundamental wave current is amplified by the power amplifier to improve the power factor. Multiple 5-10KW power modules are used in parallel as the main power module to improve the stability of the power supply. At the same time, the switching frequency of the low-power power supply is relatively high, which provides sufficient inductive load for the current transformer.

Description of drawings

In order to illustrate the technical solutions of the present application more clearly, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, for those of ordinary skill in the art, without creative work, the Additional drawings can be obtained from these drawings.

FIG. 1 is a schematic flowchart of the system and method of the present application.

detailed description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

The purpose of the present application is to provide a power amplifier-based current rapid amplification system and method thereof.

In this application, the power amplifier-based current rapid amplification system is mainly composed of a main power supply module, a main control module and a current rapid amplification module, and the main power supply module is composed of several power supplies with a voltage of 5-10KW in parallel.

The main power supply module is connected with the main control module, and several groups of current fast amplifying modules are connected in parallel. Each fast current amplifying module is numbered separately, and the numbers are stored in the main control module. All current fast amplification modules are connected to the main power module. The signal input terminal of the main control module is connected to the console.

Each group of current rapid amplification modules includes two signal analysis modules and a load. The two signal analysis modules are connected in parallel. The signal input terminal of the signal analysis module is connected to the main power module, and the signal output terminal is connected to the load in the current rapid amplification module. connected;

The signal analysis module includes a control switch, a filter, a high-bandwidth DA converter, a power amplifier, and a high-speed current sensor connected in sequence, wherein the control switch is connected to the main power module, and the high-speed current sensor is connected to the load.

The same current fast amplifying module contains two parallel filters. The filters filter the current and output harmonic current and transient current respectively after filtering. Among them, the power amplifier for amplifying the harmonic current signal is a full-bridge switching amplifier, and the power amplifier for the transient current signal is a full-bridge linear amplifier.

The control switch, high-speed current sensor and load are all connected with the main control module through the feedback circuit. The load is a current transformer.

In this application, the optical fiber communication is used between the modules to improve the anti-interference ability, communication rate and data accuracy of long-distance communication. The delay of the input current signal is less than 20us, and the phase accuracy error is less than 1°.

As shown in FIG. 1 , the specific operation method for rapidly amplifying current by the power amplifier-based current rapid amplification system of the present application mainly includes the following steps, taking a group of current rapid amplification modules as an example:

Step S1: According to the experimental requirements, input the maximum current and the maximum load voltage required for the test in the console, the main control module calculates the maximum inductance output by the current transformer, and determines the filter inductance according to the duty cycle of the switch operation. Based on this, the switching frequency of the main power module is set, and the main power module outputs the fundamental wave current.

Step S2: The main control module controls the control switch in the signal analysis module to turn on, and the fundamental current of the main power module is filtered by the parallel filter to output harmonic current and transient current.

Step S3: The filtered current is converted by a high-speed DA converter to output an analog signal, and then enters the power amplifier to amplify the current; the amplified transient current is input into the current transformer as the transient current signal in the initial stage.

Step S4: the harmonic current passes through the power amplifier, and after the current is amplified to the peak value, the output of the transient current is completed, the control switch is cut off, the output of the transient current is stopped, and the harmonic current signal is continuously output.

Step S5: After the amplified current passes through the high-speed current sensor, it enters the current transformer, and the high-speed current sensor senses the harmonic current and feeds it back to the main control module.

Step S6: The harmonic current enters the current transformer, and the induced current in the current transformer is fed back to the control module through the feedback circuit.

Step S7: the control module calculates the actual output filter inductance of the current transformer according to the received harmonic current and induced current, compares it with the maximum output filter inductance of the current transformer, judges the working state of the current transformer, and changes the main power supply module The switching frequency of the current amplifier maintains the peak output of the current.

In step S5, the harmonic current signal is amplified by the full-bridge switching amplifier, the transient current signal is amplified by the full-bridge linear amplifier, the amplified current harmonic distortion rate is less than 0.2%, the nonlinear error is less than 0.2%, and the current The output accuracy error is less than 0.5%.

In step S5, the time for the harmonic current to be amplified to the peak value by the full-bridge switching amplifier is calculated, and the time for the transient current in the full-bridge linear amplifier to be amplified to the peak value is set to be the same time.

When multiple sets of fast current amplification modules are required for experiments:

According to the experimental requirements, select several groups of parallel current rapid amplification modules;

Input the number of the selected current fast amplifying module through the console and send it to the main control module. The main control module selects the current fast amplifying module according to the number, and uniformly controls the selected current fast amplifying module;

According to the experimental requirements, input the maximum current and the maximum load voltage required for rapid amplification of each group of currents in the console, the main control module calculates the maximum inductance of the current transformer output, and determines the filter inductance according to the duty cycle of the switch operation, to Based on this, the switching frequency of the main power module is set respectively, and the main power module outputs the fundamental wave current;

Each group of current rapid amplification modules is tested with reference to the above steps S1-S7.

Example 1:

The experimental requirements are that the maximum output current is 2000A, the current rise time is less than 500us, the output time is less than 10s, the harmonic frequency is 0-100kHz, and the load voltage capability of the equipment is 50V. The load is a current transformer.

Select a group of current rapid amplification modules for experiment, the console sends the selected current rapid amplification module number and required current type information to the main control module, and the main control module uniformly controls the selected current rapid amplification The control switch of the module; and the filter mode of the filter is set to transient current and harmonic current respectively.

The main control module determines the maximum inductance of the current transformer according to the maximum current:

If it is known, the loaded peak voltage is 50×1.414=70.7V;

The maximum output current is 2000A, then the maximum peak current is 2000×1.414=2828A;

The maximum current rise time in the experiment is 500uS; and

The maximum inductance of the readily available load

Therefore, the inductive load output by the device must be less than 12.5uH.

Determine the output filter inductance according to the duty cycle of the switching operation and the calculated output inductance of the device:

When the control switch is working, the duty cycle is greater than 80%. Therefore, the filter inductance is 4 times the inductive reactance of the output load, that is, L=50uH, and the switching frequency is set to 100kHz.

Turn on the control switch in the analysis module, and the output current of the main power module is changed into harmonic current and transient current through the filtering process of the filter.

The filter current passes through the full-bridge switching amplifier, the switching frequency is 100kHz, the voltage of the full-bridge switching amplifier is 80V, and the filter inductor is 50uH.

Time required for current to go from 0A to peak value (2828A)

The current rise time of the transient current full-bridge linear amplifier is set to 450uS, and the output time is set to 2.45mS.

The transient current provides the transient current signal in the initial stage. After 2.45mS, the harmonic current reaches the peak value, the transient signal output is completed, the control switch is cut off, and the harmonic current signal is continuously output.

In the process of harmonic current output, the high-speed current sensor senses the amplified harmonic current and feeds it back to the main control module, and the induced current in the current transformer is fed back to the control module through the feedback circuit.

The main control module judges the output state of the harmonic current according to the feedback information received from the high-speed current sensor;

When it is judged that the harmonic current cannot meet the experimental requirements, the actual output inductance of the current transformer is calculated through the induced current fed back by the current transformer;

And compare the actual output inductance of the current transformer with the maximum output inductance of 12.5uH;

According to the change of the actual output inductance, the switching frequency is adjusted and changed to maintain the peak output of the harmonic current.

In this application, the current amplification mode is changed, and the fundamental wave current is amplified by the power amplifier to improve the power factor. Multiple 5-10KW power modules are used in parallel as the main power module to improve the stability of the power supply. At the same time, the switching frequency of the low-power power supply is relatively high, which provides sufficient inductive load for the current transformer.

Using multiple power modules in parallel, no high-power devices are required, which can reduce the weight of the power supply, facilitate on-site handling and testing, and improve the practicability of experimental equipment.

The present application has been described in detail above with reference to the specific embodiments and exemplary examples, but these descriptions should not be construed as a limitation on the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, various equivalent replacements, modifications or improvements can be made to the technical solutions and embodiments of the present application, which all fall within the scope of the present application. The scope of protection of the present application is determined by the appended claims.

Claims

A fast current amplification system based on a power amplifier, characterized in that it comprises: a main power supply module, a main control module and a fast current amplification module, the main power supply module is connected with the main control module, and a plurality of fast current amplification modules are connected in parallel , connected to the main power supply module, each group of the fast current amplification modules includes two signal analysis processing modules and a load, the two signal analysis modules are connected in parallel, the input end of the signal analysis module is connected to the main power supply module, and the output end Connect to the load in the same current fast amplification module;

The signal analysis module includes a control switch, a filter, a high-bandwidth DA converter, a power amplifier and a high-speed current sensor connected in sequence, the control switch is connected to the main power module, and the high-speed current sensor is connected to a load;

The control switch, the high-speed current sensor and the load are all connected with the main control module through a feedback circuit;

The main control module is configured to perform the following steps:

Set the value of the maximum current and input it into the control module, and calculate the maximum inductance of the load through the maximum current;

According to the duty cycle of the control switch, determine the output filter inductance, and set the current switching frequency of the main power module;

Set the filter mode of the filter, set the filter mode of one filter in the same current fast amplification module to harmonic current, and set the filter mode of the other filter to transient current;

Receive the inductive current value fed back by the high-speed current sensor and the load inductance fed back by the load, and calculate the actual output inductance;

According to the maximum output inductance of the load, judge the working state of the load, change the switching frequency of the current, and keep the current output of the current amplifier at the peak value.
The system for fast current amplification based on a power amplifier according to claim 1, wherein the power amplifiers in the two parallel signal analysis modules are respectively a full-bridge switching amplifier and a full-bridge linear amplifier.
The fast current amplification system based on a power amplifier according to claim 1, wherein the load is a current transformer, and the control end of the current transformer is connected to a control module.
The fast current amplification system based on a power amplifier according to claim 1, wherein the main power supply module is composed of several power supplies with a voltage of 5-10KW in parallel.
A method for rapid current amplification, based on the power amplifier-based rapid current amplification system according to any one of claims 1-4, characterized in that it comprises the following steps:

Select several groups of independent current rapid amplification modules, and uniformly control the control switches of the current rapid amplification modules through the control module;

The current of the power module passes through the filter of the parallel signal analysis module respectively, and the filter selects the harmonic current and the transient current respectively;

Determine the maximum inductance of the load according to the maximum current, and determine the output filter inductance according to the duty cycle of the switching operation, set the switching frequency of the current, and control the output current of the main power module;

The filtered transient current and harmonic current are respectively sampled by the parallel high-speed DA converter, and the current is amplified by the power amplifier. The over-amplified transient current is used as the transient current signal in the initial stage and is input to the current mutual inductance. in the device;

The harmonic current is amplified by the power amplifier, and after the current is amplified to the peak value, the transient current output is completed, the control switch is cut off, the output of the transient current is stopped, and the harmonic current signal is continuously output;

The high-speed current sensor senses the amplified harmonic current and feeds it back to the control module through the feedback circuit; at the same time, the induced current in the current transformer is fed back to the control module through the feedback circuit;

The main control module monitors the harmonic current status in real time according to the received harmonic current and induced current;

Monitored that the harmonic current is not at the peak value, the main control module compares the maximum output inductance of the current transformer according to the actual output inductance of the induced current current transformer, judges the working state of the current transformer, changes the current frequency, and makes the current amplifier reach the current output peak.
The method for rapid current amplification according to claim 5, wherein the harmonic current is amplified by a full-bridge switching amplifier, and the transient signal is amplified by a full-bridge linear amplifier.
The method for fast current amplification according to claim 5, characterized in that, the method for judging the working state of the current transformer is to calculate the maximum filter inductance of the current transformer, and compare it with the actual output filter inductance of the feedback current transformer. Compare and judge the working state of the current transformer.
The method for rapid current amplification according to claim 7, wherein the output filter inductance of the current transformer is

Among them: U is the maximum voltage of the load, s is the current rise time, and I is the maximum current.
The method for rapid current amplification according to claim 7, wherein the inductive reactance of the output load is determined according to the maximum inductance of the output load, the maximum load voltage and the switching duty cycle.