阅读说明：本技术 一种三级式变频交流发电系统数字采样系统 (Digital sampling system of three-level variable-frequency alternating-current power generation system ) 是由 李伟林 王雨峰 董润 徐梓潇 杨敬儒 于 2020-06-05 设计创作，主要内容包括：本发明涉及一种三级式变频交流发电系统数字采样系统。采用隔离措施避免损坏采样和输出设备；对不同类型的信号采用了结构相似的设计,降低了系统的复杂程度；通过该方法能够进一步提升采样的精度和速度,有效提升了系统的可靠性和效率。设计了专用的电压隔离结构,该结构在进行电压隔离的同时,使用3个光耦隔离器共同检测电压,由于使用了不同的光耦隔离器,其非线性的范围也不同,再结合电压计算模型的使用,避免了由于光耦隔离器的非线性效应带来的误差。(The invention relates to a digital sampling system of a three-level variable-frequency alternating-current power generation system. Isolation measures are adopted to avoid damaging sampling and output equipment; the design with similar structure is adopted for different types of signals, so that the complexity of the system is reduced; by the method, the sampling precision and speed can be further improved, and the reliability and efficiency of the system are effectively improved. The special voltage isolation structure is designed, when voltage isolation is carried out, the structure uses 3 optical coupler isolators to jointly detect voltage, different optical coupler isolators are used, the nonlinear ranges of the optical coupler isolators are different, and errors caused by the nonlinear effect of the optical coupler isolators are avoided by combining with the voltage calculation model.)

1. The utility model provides a three-level formula frequency conversion AC power generation system digit sampling system which characterized in that:

comprises a voltage sampling part and a current sampling part; the voltage sampling part comprises a voltage isolation module, a voltage conditioning module, a voltage filtering module and a voltage I/O module; the current sampling part comprises a current transformer, a current conditioning module, a current filtering module and a current I/O module;

the voltage isolation module is connected to the three-phase output of the generator and isolates the input voltage; the output signal of the voltage isolation module is sent to a voltage conditioning module to condition a 115VAC variable frequency signal of the power generation system into a 0-3.3V direct current digital signal; then the voltage filtering module filters and suppresses ripples of the signals in a mode of combining a transient suppressor and a low-pass filter, and then the signals are input into a voltage I/O module of the DSP;

the current transformer converts three-phase output current of the generator into a voltage signal to be output, then the current conditioning module conditions an alternating current signal output by the current transformer into a 0-3.3V direct current digital signal, finally the current filtering module performs surge suppression on the signal by using a transient filter, and then the signal is input into a current I/O module of the DSP.

2. The digital sampling system of the three-stage variable frequency ac power generation system according to claim 1, wherein: the voltage isolation module comprises a voltage division module and an optical coupling isolation module; the voltage division module comprises 3 identical voltage division outputs, the 3 voltage division outputs correspond to 3 voltage division resistors which are connected in series in the voltage division module, and the 3 voltage division output signals reduce input voltage signals by 100 times;

each path of voltage division output signal is connected to one optical coupler isolator, and the nonlinear ranges of 3 optical isolators corresponding to the 3 paths of voltage division output signals are guaranteed to be different; namely 3 paths of completely same partial pressure are output to 3 different optical isolators; voltage signals output by the optical isolator are input into the DSP through the voltage conditioning module, the voltage filtering module and the voltage I/O module;

thereby the 3-path voltage signal U output by the generator₁、U₂、U₃Each path of the voltage divider is divided into 3 paths of voltage division output by a voltage division module, and 9 paths of voltage signals are totally U₁₁、U₁₂、U₁₃、U₂₁、U₂₂、U₂₃、U₃₁、U₃₂、U₃₃(ii) a The 9 voltage signals are processed and then input into the DSP; the DSP divides the 9 input voltage signals into 3 groups, each group corresponds to one output of the three-phase power of the generator, namely U₁₁、U₁₂、U₁₃Are in a group, U₂₁、U₂₂、U₂₃Are in a group, U₃₁、U₃₂、U₃₃Are a group;

the DSP inputs the voltage signal of each group into a voltage calculation model to obtain an accurate voltage value, namely U₁₁、U₁₂、U₁₃Calculating a model for a set of input voltages to obtain U₁₀，U₂₁、U₂₂、U₂₃Calculating a model for a set of input voltages to obtain U₂₀，U₃₁、U₃₂、U₃₃Calculating a model for a set of input voltages to obtain U₃₀。

3. The modeling method of the voltage calculation model of the digital sampling system of the three-level variable frequency alternating current power generation system according to claim 2, characterized by comprising the following steps:

1) building a high-voltage source, so that the maximum output voltage of the high-voltage source is greater than the voltage output peak voltage of the generator, and the high-voltage source has a voltage output signal of the high-voltage source and can be directly collected by a computer;

2) connecting the same voltage sampling part as the generator to the high-voltage source, namely requiring the voltage sampling part connected with the high-voltage source to have the exact same voltage sampling part as the voltage sampling part actually connected to the generator;

3) starting a test to enable a high-voltage source to carry out voltage scanning, wherein the scanning range covers from 0 to the voltage output peak voltage of the generator; the voltage output by the high-voltage source is divided into 3 paths of divided voltage by the voltage dividing module of the voltage sampling part to be output; the 3 paths of voltage signals are processed by a voltage conditioning module, a voltage filtering module and a voltage I/O module and then input into the DSP; the DSP inputs 3 paths of voltage signals V₁、V₂、V₃Sending to a computer; computer synchronously obtains voltage signal V directly input by high-voltage source₄；

4) Establishing a matrix (V) in a computer₁,V₂,V₃,V₄) (ii) a After multiple frequency sweeps, a database can be obtained, so that any V can be used₄All have corresponding multiple groups (V)₁,V₂,V₃) Corresponding to it;

5) constructing a model, wherein the model has 3 input quantities X, Y, Z which respectively correspond to the voltage input quantities of each group acquired by the DSP; 1 output quantity M corresponding to the output voltage of the transformer, and the calculation method of M is to calculate K ═ X-V₁)²+(Y-V₁)²+(Z-V₁)²(ii) a Traversing and calculating K in the database obtained in the step 4), wherein M is equal to (V) when K is minimum₁,V₂,V₃,V₄) V in₄And completing modeling.

Technical Field

The invention relates to the field of electrical equipment and electrical engineering, in particular to a digital sampling system of a high-voltage variable-frequency alternating-current three-stage variable-frequency alternating-current power generation system applied to the field of civil aviation.

Background

The voltage stabilization Control device, also called as a Generator Control Unit (GCU), is a main controller of the onboard power system. At present, a digital voltage stabilization control device adopted by an airplane power supply system in China is mainly a semi-digital voltage stabilization control device. The semi-digital GCU takes a single chip microcomputer as a core and integrates a power supply system control function, a power supply system real-time protection function, a GCU self-detection function, a GCU fault diagnosis isolation function, an upper computer communication function and the like. Compared with a digital signal processing chip, the performance of the voltage stabilization control device taking the single chip microcomputer as a core is limited by the function of the single chip microcomputer chip, firstly, the single chip microcomputer is in a disadvantage in the aspects of response speed, adjustable resources, precision and the like, and secondly, the voltage stabilization function of the half-digital GCU is realized by means of an analog circuit when the half-digital GCU is applied to a voltage regulation environment with higher dynamic characteristics; finally, the semi-digital GCU needs to realize the voltage regulation function by means of an external analog circuit, so that the semi-digital GCU has disadvantages in maintainability, expansibility and reliability, and has the disadvantages of low automation degree, low response speed and the like. This makes the semi-digital GCU no longer in line with the development of high precision, high speed and high versatility of voltage stabilization control device design.

In order to solve the problems of the prior art, a novel all-digital GCU structure with a high-performance Digital Signal Processor (DSP) as a core is proposed. The structure fully embodies the characteristics of high speed, high precision and high compatibility of the DSP, and can utilize the strong digital signal processing capability to complete the operation of a high-precision complex algorithm at high speed.

In order to realize the function of voltage stabilization control using a DSP, the power generation condition of the system needs to be monitored in real time. Unlike the conventional semi-digital voltage stabilization control device, the digital signal processing chip can only process digital signals. Therefore, the analog signal needs to be sampled and conditioned, and the sampled signal needs to be reasonably filtered by the peripheral circuit, so that the analog signal is converted into a digital signal, and the real-time condition of the system can be digitally reconstructed by the internal algorithm of the DSP.

For voltage stabilization control equipment, instantaneous voltage and current of a system are necessary system parameters, and high-precision analog signal sampling and high-fidelity conditioning are the preconditions of system control precision. In addition, airborne power supply equipment has high power density and high real-time power, and needs to be isolated from a power circuit and a digital circuit when signals are acquired, so that the equipment is prevented from being damaged.

With the gradual popularization of the variable frequency power supply system, the traditional analog GCU and the semi-digital GCU cannot meet the voltage regulation and protection requirements of the variable frequency power supply system. In order to enable the full digital voltage stabilization control device to function, it is necessary to develop a digital sampling method for a variable frequency ac power generation system.

In addition, voltage isolation is generally needed when high voltage is adopted, the optical coupler isolator is most applied, but different optical coupling parts of the optical coupler isolator have certain nonlinear ranges due to the property of the optical coupler isolator, and the possible error is large if the voltage range is large.

Disclosure of Invention

In view of the above, to solve the above problems, a digital sampling system for a three-level variable frequency ac power generation system is provided.

For voltage stabilization control equipment, instantaneous voltage and current of a system are necessary system parameters, and high-precision analog signal sampling and high-fidelity conditioning are the preconditions of system control precision. The invention adopts a mixed structure of conditioning and filtering, and inputs analog signals into a digital signal processing chip after filtering after reducing the analog signals in equal proportion aiming at the input range of an I/O port of the digital signal processing chip.

The technical scheme adopted by the invention is as follows:

the voltage sampling adopts the method of isolation, conditioning and filtering. First, a digital signal processing chip is a typical digital circuit device. The digital circuit has high precision and low power, and the fluctuation of the analog signal easily causes the damage of the sampling circuit. Therefore, before the analog signal enters the digital circuit, the analog signal needs to pass through an isolation circuit to avoid the irreversible influence of the fluctuation of the analog signal on the digital circuit. Secondly, the types of the digital signal processing chips are different, so that in the process of conditioning the voltage instantaneous value, the circuit design needs to be carried out according to the types of the digital signal processing chips, so that the range of the conditioned signal is input at the voltage of the I/O port of the DSP chip. Third, the conditioning circuit introduces interference from the power supply in the digital circuit into the conditioned voltage signal. Therefore, a low-pass filter is required to be introduced between the I/O interface of the DSP chip and the output of the conditioning circuit for ripple suppression and filtering. Through the three steps, the voltage signal instantaneous value required by the voltage stabilization control device can be accurately input into the DSP chip for algorithm use.

The current sampling structure is similar to the voltage sampling structure and needs three processes of signal conversion, conditioning and filtering. The signal conversion means that the I/O interface of the digital signal processing chip cannot recognize the current signal, so that the current signal needs to be converted into a voltage signal by using a sampling resistor, a transformer or the like. This step may implement the isolation function depending on the particular method employed. Secondly, the sampled current signal needs to pass through a conditioning circuit in the form of a voltage signal, and the main purpose of the step is to enable the maximum value of the current signal to be as close as possible to the input range of an I/O interface of the DSP, and meanwhile, a margin is reserved, so that DSP damage caused by overload is avoided. And finally, filtering measures such as a transient suppressor are connected between the conditioning output interface and the input interface of the DSP, so that the adverse effect of surge pulse on the equipment is avoided.

Comprises a voltage sampling part and a current sampling part; the voltage sampling part comprises a voltage isolation module, a voltage conditioning module, a voltage filtering module and a voltage I/O module; the current sampling part comprises a current transformer, a current conditioning module, a current filtering module and a current I/O module;

the voltage isolation module is connected to the three-phase output of the generator and isolates the input voltage; the output signal of the voltage isolation module is sent to a voltage conditioning module to condition a 115VAC variable frequency signal of the power generation system into a 0-3.3V direct current digital signal; then the voltage filtering module filters and suppresses ripples of the signals in a mode of combining a transient suppressor and a low-pass filter, and then the signals are input into a voltage I/O module of the DSP;

the current transformer converts three-phase output current of the generator into a voltage signal to be output, then the current conditioning module conditions an alternating current signal output by the current transformer into a 0-3.3V direct current digital signal, finally the current filtering module performs surge suppression on the signal by using a transient filter, and then the signal is input into a current I/O module of the DSP.

The voltage isolation module comprises a voltage division module and an optical coupling isolation module; the voltage division module comprises 3 identical voltage division outputs, the 3 voltage division outputs correspond to 3 voltage division resistors which are connected in series in the voltage division module, and the 3 voltage division output signals reduce input voltage signals by 100 times;

each path of voltage division output signal is connected to one optical coupler isolator, and the nonlinear ranges of 3 optical isolators corresponding to the 3 paths of voltage division output signals are guaranteed to be different; namely 3 paths of completely same partial pressure are output to 3 different optical isolators; voltage signals output by the optical isolator are input into the DSP through the voltage conditioning module, the voltage filtering module and the voltage I/O module;

thereby the 3-path voltage signal U output by the generator₁、U₂、U₃Each path of the voltage divider is divided into 3 paths of voltage division output by a voltage division module, and 9 paths of voltage signals are totally U₁₁、U₁₂、U₁₃、U₂₁、U₂₂、U₂₃、U₃₁、U₃₂、U₃₃(ii) a The 9 voltage signals are processed and then input into the DSP; the DSP divides the 9 input voltage signals into 3 groups, each group corresponds to one output of the three-phase power of the generator, namely U₁₁、U₁₂、U₁₃Are in a group, U₂₁、U₂₂、U₂₃Are in a group, U₃₁、U₃₂、U₃₃Are a group;

the DSP inputs the voltage signal of each group into a voltage calculation model to obtain an accurate voltage value, namely U₁₁、U₁₂、U₁₃Calculating a model for a set of input voltages to obtain U₁₀，U₂₁、U₂₂、U₂₃Calculating a model for a set of input voltages to obtain U₂₀，U₃₁、U₃₂、U₃₃Calculating a model for a set of input voltages to obtain U₃₀。

A modeling method of a voltage calculation model of a digital sampling system of a three-level variable-frequency alternating-current power generation system is characterized by comprising the following steps:

1) building a high-voltage source, so that the maximum output voltage of the high-voltage source is greater than the voltage output peak voltage of the generator, and the high-voltage source has a voltage output signal of the high-voltage source and can be directly collected by a computer;

2) connecting the same voltage sampling part as the generator to the high-voltage source, namely requiring the voltage sampling part connected with the high-voltage source to have the exact same voltage sampling part as the voltage sampling part actually connected to the generator;

3) starting a test to enable a high-voltage source to carry out voltage scanning, wherein the scanning range covers from 0 to the voltage output peak voltage of the generator; the voltage output by the high-voltage source is divided into 3 paths of divided voltage by the voltage dividing module of the voltage sampling part to be output; the 3 paths of voltage signals are processed by a voltage conditioning module, a voltage filtering module and a voltage I/O module and then input into the DSP; the DSP inputs 3 paths of voltage signals V₁、V₂、V₃Sending to a computer; computer synchronously obtains voltage signal V directly input by high-voltage source₄；

4) Establishing a matrix (V) in a computer₁,V₂,V₃,V₄) (ii) a After multiple frequency sweeps, a database can be obtained, so that any V can be used₄All have corresponding multiple groups (V)₁,V₂,V₃) Corresponding to it;

5) constructing a model, wherein the model has 3 input quantities X, Y, Z which respectively correspond to the voltage input quantities of each group acquired by the DSP; 1 output quantity M corresponding to the output voltage of the transformer, and the calculation method of M is to calculate K ═ X-V₁)²+(Y-V₁)²+(Z-V₁)². Traversing and calculating K in the database obtained in the step 4), wherein M is equal to (V) when K is minimum₁,V₂,V₃,V₄) V in₄And completing modeling.

At the moment, because the working nonlinear effects of different optical couplers are different, a plurality of optical couplers are commonly used, a voltage is measured for a plurality of times, and a measurement result is input into a voltage calculation model.

The invention has the beneficial effects that: isolation measures are adopted to avoid damaging sampling and output equipment; the design with similar structure is adopted for different types of signals, so that the complexity of the system is reduced; by the method, the sampling precision and speed can be further improved, and the reliability and efficiency of the system are effectively improved.

The special voltage isolation structure is designed, when voltage isolation is carried out, the structure uses 3 optical coupler isolators to jointly detect voltage, different optical coupler isolators are used, the nonlinear ranges of the optical coupler isolators are different, and errors caused by the nonlinear effect of the optical coupler isolators are avoided by combining with the voltage calculation model.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosed subject matter, are incorporated in and constitute a part of this specification. The drawings illustrate the implementations of the disclosed subject matter and, together with the detailed description, serve to explain the principles of implementations of the disclosed subject matter. No attempt is made to show structural details of the disclosed subject matter in more detail than is necessary for a fundamental understanding of the disclosed subject matter and various modes of practicing the same.

FIG. 1 is a schematic diagram of a voltage sampling method;

FIG. 2 is a schematic diagram of a current sampling method;

FIG. 3 is a schematic diagram of a voltage isolation module for voltage sampling;

FIG. 4 is a schematic diagram of a voltage calculation model modeling method.

Detailed Description

The advantages, features and methods of accomplishing the same will become apparent from the drawings and the detailed description that follows.

With reference to fig. 1-2, a digital sampling system of a three-level variable frequency ac power generation system.

The voltage sampling method of the present embodiment is shown in fig. 1, and the current sampling method is shown in fig. 2, and includes the following steps:

the voltage signal sampling comprises the following steps. Firstly, an isolation chip is adopted to carry out electrical isolation on voltage signal input and output, and the functions of protecting a conditioning circuit and a digital signal processing chip are realized. Secondly, a conditioning circuit is formed by an analog circuit and an operational amplifier, and a 115VAC variable frequency signal of the power generation system is conditioned into a 0-3.3 VDC digital signal, so that the DSP can recognize and read. And finally, before being output to the DSP, the signal is filtered and subjected to ripple suppression in a mode of combining a transient suppressor and a low-pass filter, so that the precision of signal acquisition is improved. The voltage signal is collected through the steps.

The current signal sampling comprises the following steps. Firstly, a current transformer is adopted for signal conversion, and a current signal is converted into a voltage signal form. Due to the adoption of the current transformer, the step actually comprises the function of electrical isolation. Secondly, a conditioning circuit is adopted to condition the voltage signal form of the alternating current signal to be within the range of 0-3.3 VDC. Finally, the transient filter is used for carrying out surge suppression on the signal, and the circuit is protected. The current signal is acquired through the steps.

Comprises a voltage sampling part and a current sampling part; the voltage sampling part comprises a voltage isolation module, a voltage conditioning module, a voltage filtering module and a voltage I/O module; the current sampling part comprises a current transformer, a current conditioning module, a current filtering module and a current I/O module;

the voltage isolation module is connected to the three-phase output of the generator and isolates the input voltage; the output signal of the voltage isolation module is sent to a voltage conditioning module to condition a 115VAC variable frequency signal of the power generation system into a 0-3.3V direct current digital signal; then the voltage filtering module filters and suppresses ripples of the signals in a mode of combining a transient suppressor and a low-pass filter, and then the signals are input into a voltage I/O module of the DSP;

the current transformer converts three-phase output current of the generator into a voltage signal to be output, then the current conditioning module conditions an alternating current signal output by the current transformer into a 0-3.3V direct current digital signal, finally the current filtering module performs surge suppression on the signal by using a transient filter, and then the signal is input into a current I/O module of the DSP.

The voltage isolation module comprises a voltage division module and an optical coupling isolation module; the voltage division module comprises 3 identical voltage division outputs, the 3 voltage division outputs correspond to 3 voltage division resistors which are connected in series in the voltage division module, and the 3 voltage division output signals reduce input voltage signals by 100 times;

each path of voltage division output signal is connected to one optical coupler isolator, and the nonlinear ranges of 3 optical isolators corresponding to the 3 paths of voltage division output signals are guaranteed to be different; namely 3 paths of completely same partial pressure are output to 3 different optical isolators; voltage signals output by the optical isolator are input into the DSP through the voltage conditioning module, the voltage filtering module and the voltage I/O module;

thereby the 3-path voltage signal U output by the generator₁、U₂、U₃Each path of the voltage divider is divided into 3 paths of voltage division output by a voltage division module, and 9 paths of voltage signals are totally U₁₁、U₁₂、U₁₃、U₂₁、U₂₂、U₂₃、U₃₁、U₃₂、U₃₃(ii) a The 9 voltage signals are processed and then input into the DSP; the DSP divides the 9 input voltage signals into 3 groups, each group corresponds to one output of the three-phase power of the generator, namely U₁₁、U₁₂、U₁₃Are in a group, U₂₁、U₂₂、U₂₃Are in a group, U₃₁、U₃₂、U₃₃Are a group;

the DSP inputs the voltage signal of each group into a voltage calculation model to obtain an accurate voltage value, namely U₁₁、U₁₂、U₁₃Calculating a model for a set of input voltages to obtain U₁₀，U₂₁、U₂₂、U₂₃Calculating a model for a set of input voltages to obtain U₂₀，U₃₁、U₃₂、U₃₃Is a set of input voltagesCalculating the model to obtain U₃₀。

With reference to fig. 3-4, a modeling method of a voltage calculation model of a digital sampling system of a three-level variable frequency ac power generation system is characterized by comprising the following steps:

1) building a high-voltage source, so that the maximum output voltage of the high-voltage source is greater than the voltage output peak voltage of the generator, and the high-voltage source has a voltage output signal of the high-voltage source and can be directly collected by a computer;

2) connecting the same voltage sampling part as the generator to the high-voltage source, namely requiring the voltage sampling part connected with the high-voltage source to have the exact same voltage sampling part as the voltage sampling part actually connected to the generator;

3) starting a test to enable a high-voltage source to carry out voltage scanning, wherein the scanning range covers from 0 to the voltage output peak voltage of the generator; the voltage output by the high-voltage source is divided into 3 paths of divided voltage by the voltage dividing module of the voltage sampling part to be output; the 3 paths of voltage signals are processed by a voltage conditioning module, a voltage filtering module and a voltage I/O module and then input into the DSP; the DSP inputs 3 paths of voltage signals V₁、V₂、V₃Sending to a computer; computer synchronously obtains voltage signal V directly input by high-voltage source₄；

4) Establishing a matrix (V) in a computer₁,V₂,V₃,V₄) (ii) a After multiple frequency sweeps, a database can be obtained, so that any V can be used₄All have corresponding multiple groups (V)₁,V₂,V₃) Corresponding to it;

5) constructing a model, wherein the model has 3 input quantities X, Y, Z which respectively correspond to the voltage input quantities of each group acquired by the DSP; 1 output quantity M corresponding to the output voltage of the transformer, and the calculation method of M is to calculate K ═ X-V₁)²+(Y-V₁)²+(Z-V₁)². Traversing and calculating K in the database obtained in the step 4), wherein M is equal to (V) when K is minimum₁,V₂,V₃,V₄) V in₄And completing modeling.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.