Energy storage converter device sampling design method based on code generation technology

Abstract

The invention provides a code generation technology-based sampling design method for an energy storage converter device, which is characterized in that the energy storage converter device adopts a diode clamping type NPC, an alternating current side output adopts an LCL filter, and sampling points are designed according to the requirements of a control algorithm and comprise current sampling and voltage sampling of a direct current side; the sampling part comprises a Hall voltage and current sensor and a signal conditioning circuit, voltage and current values collected by the Hall voltage and current sensor pass through the signal conditioning circuit and then are input into a TMS320F28379D core board, and after A / D conversion and per-unit processing are carried out in the core board, the voltage and current values act on a control algorithm; in the sampling design process, visual program design based on a Matlab / Simulink development environment is achieved through an F28379D development board.

Description

Technical Field

[0001] The invention belongs to the technical field of power electronics and relates to an energy storage converter. Background Art

[0002] As the proportion of new energy in primary energy consumption continues to increase, China's new energy installed capacity will maintain rapid growth in the future. However, new energy power generation has the characteristics of randomness and volatility, which has a great negative impact on the stability of traditional power systems. Energy storage systems can store electricity when energy is abundant and release electricity when demand peaks. Therefore, as an important part of energy conversion and storage, energy storage systems play a key role in balancing grid loads, improving energy utilization efficiency, and responding to power fluctuations. The sampling part plays an important role as a bridge between the primary and secondary side controls of the energy storage converter device. The accuracy of the sampling part directly affects the accuracy of the control algorithm. Summary of the invention

[0003] The purpose of the present invention is to provide a sampling design method for an energy storage converter device. The sampling design method for an energy storage converter device provided by the present invention has sampling points designed according to the requirements of a control algorithm, and can achieve accurate sampling. The technical solution is as follows:

[0004] The invention discloses a sampling design method for an energy storage converter device based on code generation technology. The energy storage converter device adopts a diode clamped NPC, and an AC side output adopts an LCL filter. The method is characterized in that sampling points are designed according to the requirements of a control algorithm, including current sampling and voltage sampling on the DC side, and sampling of filter inductor current and filter capacitor voltage on the AC side. The sampling part comprises a Hall voltage and current sensor and a signal conditioning circuit. The voltage and current values ​​collected by the Hall voltage and current sensor are input into a TMS320F28379D core board after passing through the signal conditioning circuit, and are applied to the control algorithm after A / D conversion and standardization are performed inside the core board. In the sampling design process, a visual program design based on a Matlab / Simulink development environment is realized through an F28379D development board.

[0005] Furthermore, in the design of AC side filter capacitor voltage sampling, it is determined that the range of the AC side voltage sensor is at least greater than:

[0006]

[0007] According to the output voltage and current range, select the output side sampling resistor R2 = 430Ω,

[0008] According to the turns ratio of the sensor, the input current on the primary side, and the sampling resistor R1=80kΩ on the input side, the sampling range of the AC side voltage is determined:

[0009] UAB =I p R1=744V.

[0010] Furthermore, in the DC side voltage sampling design, according to the DC side battery cluster voltage, the DC voltage sampling circuit selects two sampling resistors of R2=430Ω and R1=66kΩ, and determines that the sampling range of the DC side voltage is 614V.

[0011] Furthermore, in the design of current sampling on the DC side and current sampling of the filter inductor on the AC side: according to the rated input current on the primary side, the corresponding rated output current on the secondary side and the conversion rate of the sensor, the sampling resistor on the secondary side is determined to be 100Ω.

[0012] Furthermore, in the sampling program design based on code generation, the Matlab / Simulink development environment is used as the basis to realize visual program design, and the Instruments Control Toolbox and DSP System Toolbox toolbox are used to realize the host computer communication function, and the current or voltage experimental data sampled by the converter is observed. The software design of the sampling program is divided into data acquisition and sampling correction.

[0013] Furthermore, in the data acquisition program design, the data acquisition part uses the ADC port pin corresponding to the DSP, and in the sampling process, adopts the average value filtering method. The specific method is: after accumulating the results of four consecutive samplings, the shift module shifts the accumulated results right by two places.

[0014] Furthermore, in the design of the sampling correction program, the specific operation process of the sampling correction and normalization is: through the above-mentioned sampling link, a digital signal is obtained. Since the polarity of the signal conditioning circuit is opposite to that of the Hall sensor output signal, the polarity of the input digital signal is inverted and then superimposed by 2048, so that the polarity of the collected data can be consistent with the polarity of the Hall sensor.

[0015] Furthermore, based on the principle of serial communication, the collected voltage and current waveforms of the converter are observed by the host computer during the experiment in order to analyze the experimental results. The host computer first sets the communication COM port of the serial port through the serial port parameter configuration module, specifies the serial port transmission rate and the number of data bits of the transmission interface; then, the serial data receiving module is used to configure the communication port that is effective at the beginning of program execution, as well as the size and data type of the output parameters; then, the serial data receiving module outputs the collected data to the data processing module for conversion, and finally outputs the processed data to the Scope to display and analyze the waveforms obtained in the experiment.

[0016] The present invention provides a sampling design method for an energy storage converter device based on Matlab / Simulink code generation technology, which can observe the voltage and current waveforms of the converter in real time with a host computer monitoring program, so as to facilitate real-time control. When sampling abnormality is observed, PWM blocking can be performed with a protection program. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Energy storage converter hardware structure

[0018] Figure 2 Voltage sampling circuit

[0019] Figure 3 Current sampling circuit

[0020] Figure 4 Signal conditioning circuit schematic

[0021] Figure 5 Code Generation Software Development Structure

[0022] Figure 6 Data collection procedures

[0023] Figure 7 Sampling Calibration and Normalization Procedure

[0024] Figure 8 Host computer control and monitoring interface DETAILED DESCRIPTION

[0025] The present invention is described below in conjunction with the accompanying drawings and embodiments.

[0026] The specific working process of the device is as follows: first, AC and DC pre-charging is performed, and the DC side capacitor voltage, AC side capacitor voltage and inductor current are collected using Hall sensors, and are sent to the TMS320F28379D core board after being processed by the signal conditioning circuit. A / D conversion and standardization, control algorithm operation and SVPWM modulation are performed inside the core board, and then SVPWM pulse signals are output. After being isolated and amplified by the FPGA protection and drive circuit, the switch tube is driven to work.

[0027] The three-level topology adopted by the device is the diode-clamped NPC (Neutral-Point Clamped) type. The AC side output adopts an LCL filter. The device selection is shown in Table 1. The overall structure is as follows: Figure 1 shown.

[0028] Table 1 Selection of main components of the device

[0029]

[0030] The sampling point design includes: current sampling and voltage sampling on the DC side, and sampling of filter inductor current and filter capacitor voltage on the AC side. The DC voltage regulator board design includes: DC side voltage regulator capacitor and filter capacitor design, current / voltage sampling circuit, dry contact circuit, and DC side pre-charging circuit.

[0031] The rated power of this device is 60kVA, the rated voltage of the battery cluster used is 800V, the rated line voltage of the AC side is 380V, the switching frequency is 10kHz-60kHz, and the rated current output on the AC side is calculated to be 92A. Based on the above parameters, the sampling range of the sampling circuit is designed.

[0032] 1.1.1 1 Voltage and current sampling circuit design

[0033] The A / D conversion channel of the DSP core board requires the input signal range to be 0-3V, so the sampled signal value needs to be converted. The specific idea is as follows: after passing through the voltage and current sampling circuit, the voltage and current values ​​to be collected are converted to the range of ±10V, and then through the signal conditioning circuit, they are converted to the range of 0-3V and sent to the core board.

[0034] AC voltage sampling circuit: During normal operation, the effective value of the AC side line voltage is about 380V. Considering the line voltage amplitude and the fluctuation of the grid voltage, the range of the AC side voltage sensor is at least greater than:

[0035]

[0036] The output voltage range of the voltage sampling circuit is ±10V, and the rated output current is 25mA. Select the output side sampling resistor R2 = 430Ω, according to the sensor turns ratio n = 2500:1000, the primary side input current is:

[0037]

[0038] The sampling resistor R1 = 80kΩ is selected on the input side, so that the sampling range of the AC side voltage can be obtained as follows:

[0039] U AB =I p R1=744V (3)

[0040] Similarly, half of the DC side battery cluster voltage is 400V, and the DC voltage sampling circuit selects R2=430Ω, R1=66kΩ, so the sampling range of the DC side voltage can be obtained as 614V.

[0041] Current sampling circuit: The rated input current of the primary side is 200A, corresponding to the rated output current of the secondary side is 100mA. The conversion rate of the sensor is n=1:2000. The sampling resistor on the secondary side is selected as 100Ω, which can convert the current signal of ±200A into a voltage signal of ±10V.

[0042] 1.1.2 2 Signal Conditioning Circuit Design

[0043] The circuit consists of a power supply circuit and an op amp circuit. The power supply circuit first uses A0515S to convert the input 5V signal into 15V, and then converts the 15V signal into 12V and -12V voltages through voltage conversion modules MC7812ACD2TG and MC7912ACD2TG respectively to power the op amp chip.

[0044] In order to make the output voltage signal above 0V, it is necessary to provide a bias voltage for the op amp input signal. A voltage stabilizing diode is used in the circuit to stabilize the voltage at -2.5V, and the principle of voltage follower is used to isolate the bias voltage from the previous stage to stabilize the bias voltage. The op amp uses the OPA4277UA chip. According to the virtual short and virtual open characteristics of the op amp, the op amp output voltage can be obtained as:

[0045]

[0046]

[0047] Among them, VADC is a ±10V AC signal, Vref is a bias voltage, and its magnitude is -2.5V. At this time, the 10V voltage is converted to 0V, and -10V is converted to 3V, thereby converting it into a 0-3V voltage.

[0048] 1.1.33 Sampling Program Design Based on Code Generation

[0049] The software system of this device is based on the Matlab / Simulink development environment. By building a code generation environment, it realizes the automatic generation of C code, thereby realizing visual program design based on the simulation model. Figure 5 As shown in the figure, by using Instruments Control Toolbox and DSP System Toolbox to realize the host computer communication function, the experimental data such as the current or voltage sampled by the converter can be observed to verify the accuracy of the sampling.

[0050] The software design of the sampling program is mainly divided into two parts, namely data acquisition and sampling correction. During the correction process, in order to improve the calculation speed of the control algorithm, the actual numerical value needs to be normalized and converted into a per-unit value for calculation.

[0051] (1) Data acquisition program design

[0052] The data acquisition part uses the ADC port pin corresponding to the DSP to convert the collected 0-3V analog signal into a 0-4096 digital signal. During the sampling process, the control program of the converter adopts the average filtering method. In one operation cycle, four consecutive samples are taken and then the average value is calculated, thereby reducing the random noise and improving the sampling accuracy. In order to maintain accuracy and avoid division operations when calculating the average value, the method used is as follows Figure 6 As shown, after accumulating the results of four consecutive samplings, the shift module in the system is used to shift the accumulated result right by two bits, which is equivalent to dividing the accumulated result by 4.

[0053] (2) Sampling and calibration program design

[0054] like Figure 7 As shown in the figure, the specific operation process of sampling correction and standardization is as follows: through the above sampling link, the 0-3V analog signal is converted into a digital signal, that is, 0V corresponds to a digital value of 0, and 3V corresponds to a digital value of 4096. Taking AC voltage sampling as an example, since the conditioning circuit will reverse the polarity of the Hall sensor output signal, the -10V signal output by the voltage sensor corresponds to a digital value of 4096, and 10V corresponds to a digital value of 0. At this time, the polarity of the input digital signal is reversed and then superimposed with 2048, so that the polarity of the collected data is consistent with the polarity of the Hall sensor.

[0055] Based on the principle of serial communication, the device can observe the collected waveforms of the converter voltage and current through the host computer during the experiment, so as to analyze the experimental results. In addition, the host computer can directly send control instructions, reference power values ​​or other parameters required during the experiment to the converter. The host computer control and monitoring interface is as follows: Figure 8 As shown. The host computer should first use the serial port parameter configuration module to set the communication COM port of the serial port, specify the serial port transmission rate and the number of data bits of the transmission interface; then use the serial data receiving module to configure the communication port that is effective at the beginning of program execution, as well as the size and data type of the output parameters; then, the serial data receiving module outputs the collected data to the data processing module for conversion, and finally outputs the processed data to the Scope to display and analyze the waveform obtained in the experiment.

Claims

1. A sampling design method for an energy storage converter device based on code generation technology, wherein the energy storage converter device adopts a diode clamped NPC and an AC side output adopts an LCL filter, characterized in that: The sampling points are designed according to the requirements of the control algorithm, including current sampling and voltage sampling on the DC side, and sampling of the filter inductor current and filter capacitor voltage on the AC side. The sampling part consists of a Hall voltage and current sensor and a signal conditioning circuit. The voltage and current values ​​collected by the Hall voltage and current sensor are input into the TMS320F28379D core board after passing through the signal conditioning circuit. After A / D conversion and standardization inside the core board, they are applied to the control algorithm. During the sampling design process, the F28379D development board is used to implement visual program design based on the Matlab / Simulink development environment.

2. The sampling design method according to claim 1, characterized in that: In the design of AC side filter capacitor voltage sampling, make sure that the range of the AC side voltage sensor is at least greater than: According to the output voltage and current range, select the output side sampling resistor R2 = 430Ω, According to the turns ratio of the sensor, the input current on the primary side, and the sampling resistor R1=80kΩ on the input side, the sampling range of the AC side voltage is determined: U AB =I p R1=744V。 3. The sampling design method according to claim 1, characterized in that: In the DC side voltage sampling design, according to the DC side battery cluster voltage, the two sampling resistors selected by the DC voltage sampling circuit are R2=430Ω and R1=66kΩ, and the sampling range of the DC side voltage is determined to be 614V.

4. The sampling design method according to claim 1, characterized in that: In the design of current sampling on the DC side and current sampling of the filter inductor on the AC side: according to the rated input current on the primary side, the corresponding rated output current on the secondary side and the conversion rate of the sensor, the sampling resistor on the secondary side is determined to be 100Ω.

5. The sampling design method according to claim 1, characterized in that: In the sampling program design based on code generation, the Matlab / Simulink development environment is used as the basis to realize visual program design, and the Instruments Control Toolbox and DSP System Toolbox toolbox are used to realize the host computer communication function, observe the current or voltage experimental data sampled by the converter, and the software design of the sampling program is divided into data acquisition and sampling correction.

6. The sampling design method according to claim 5, characterized in that: In the data acquisition program design, the data acquisition part uses the ADC port pin corresponding to the DSP. During the sampling process, the average value filtering method is adopted. The specific method is: after accumulating the results of four consecutive samplings, the shift module shifts the accumulated results right by two bits.

7. The sampling design method according to claim 5, characterized in that: In the design of sampling correction program, the specific operation process of sampling correction and standardization is: through the above-mentioned sampling link, a digital signal is obtained. Since the polarity of the signal conditioning circuit is opposite to that of the Hall sensor output signal, the polarity of the input digital signal is inverted and then superimposed by 2048, so that the polarity of the collected data can be consistent with the polarity of the Hall sensor.

8. The sampling design method according to claim 1, characterized in that: Based on the principle of serial communication, the voltage and current waveforms of the converter are collected and observed by the host computer during the experiment in order to analyze the experimental results. The host computer first sets the communication COM port of the serial port through the serial port parameter configuration module, specifies the serial port transmission rate and the number of data bits of the transmission interface; then, the serial data receiving module is used to configure the communication port that is effective at the beginning of program execution, as well as the size and data type of the output parameters; then, the serial data receiving module outputs the collected data to the data processing module for conversion, and finally outputs the processed data to the Scope to display and analyze the waveforms obtained in the experiment.

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