CN203011981U - DC side voltage isolation detection system applied to high voltage H-bridge cascading SVG - Google Patents
DC side voltage isolation detection system applied to high voltage H-bridge cascading SVG Download PDFInfo
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- CN203011981U CN203011981U CN 201320016887 CN201320016887U CN203011981U CN 203011981 U CN203011981 U CN 203011981U CN 201320016887 CN201320016887 CN 201320016887 CN 201320016887 U CN201320016887 U CN 201320016887U CN 203011981 U CN203011981 U CN 203011981U
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Abstract
The utility model discloses a DC side voltage isolation detection system applied to a high voltage H-bridge cascading SVG. Each cascading unit DC side capacitor of the high voltage H-bridge cascading SVG is sequentially connected to a voltage dividing circuit, a voltage-to-frequency conversion circuit, an electro-optical converter, an optical-electro converter, a frequency-to-voltage conversion circuit, and an analog-to-digital conversion circuit, wherein the electro-optical converter and the optical-electro converter are connected through multimode optical fibers; and the analog-to-digital conversion circuit is connected to a control system of a low potential side of the high voltage H-bridge cascading SVG. The DC side voltage isolation detection system disclosed by the utility model can detect DC side voltage of each of the cascading units of a high potential side rapidly and accurately, and transmit the DC side voltage to the control system of the low potential side safely in an interference-free manner.
Description
Technical field
The utility model relates to a kind of voltage isolation detection system, particularly a kind of dc voltage isolation detection system that is applicable to high pressure H bridge cascade connection type SVG.
Background technology
In recent years, in the high-power application, many level power converter technique has obtained paying close attention to widely.With the conventional full bridge inverter applications when the high pressure occasion, adopt the connection in series-parallel of power device to come the large electric current of output HIGH voltage different, novel H bridge cascaded inverter does not need a large amount of catching diodes and striding capacitance, each modular structure is identical, be easy to modularization and assembling, bear under lower voltage condition at each power device and can access higher Voltage-output, adopt advanced and mature pulse-length modulation (PWM) technology can effectively suppress and eliminate low-order harmonic, need not to adopt output filter just can obtain the good output of waveform.
The dc voltage of H bridge cascade connection type SVG is separate, and DC side does not consume active power in ideal conditions, can keep preferably the balance of each dc voltage.But in practical application, because switching characteristic, shunt loss, the dc bus capacitor of each switching device discharges and recharges the reasons such as time difference, can cause the imbalance of modules dc voltage, thereby cause output voltage and current distortion, the switching device voltage stress is uneven, or even burns the safety that switching device jeopardizes whole system.Based on this, must the dc voltage of H bridge cascade connection type SVG be detected, so that the meritorious exchange of control device and system in control system, within dc capacitor voltage is controlled at normal range.When being applied to the high pressure occasion, for the control system of the cascaded inverter part that guarantees hot side and low potential side partly realizes electrical isolation completely, traditional DC side detection method needs heavy and expensive isolation voltage transmitter.How quick and precisely to detect each cascade of hot side unit dc voltage, and the glitch-free control system that passes to low potential side of safety is to be applied to high pressure field SVG system problem needing to overcome.
Summary of the invention
Technical problem to be solved in the utility model is, not enough for prior art, a kind of dc voltage isolation detection system that is applicable to high pressure H bridge cascade connection type SVG is provided, detect rapidly and accurately each cascade of hot side unit dc voltage, and safe interference-free passes to the control system of low potential side.
For solving the problems of the technologies described above, the technical scheme that the utility model adopts is: a kind of dc voltage isolation detection system that is applicable to high pressure H bridge cascade connection type SVG, and each cascade of described high pressure H bridge cascade connection type SVG unit dc bus capacitor all is connected with bleeder circuit, voltage/frequency change-over circuit, electrical to optical converter, photoelectric commutator, frequency/voltage change-over circuit, mould/number conversion circuit in turn; Connect by multimode optical fiber between described electrical to optical converter and described photoelectric commutator; The control system of described mould/described high pressure H bridge cascade connection type SVG low potential side of number conversion circuit access.
As preferred version, described bleeder circuit is resistor voltage divider circuit, and described resistor voltage divider circuit comprises the resistance of two series connection; Described voltage/frequency change-over circuit adopts the LM331 chip; Described frequency/voltage change-over circuit adopts the LM331 chip; Described photoelectric commutator model is RX HFBR-2412TZ; Described electrical to optical converter model is TX HFBR-1414TZ; Described mould/number conversion circuit adopts A/D converter AD7656.
Compared with prior art, the beneficial effect that the utility model has is: connect by multimode optical fiber between the utility model electrical to optical converter and photoelectric commutator, not only realized the electrical isolation of main circuit unit and control module, promoted Security of the system, and the good anti-interference of multimode optical fiber makes also the measurement transmission more accurate; The acp chip that the integrated chip LM331 that adopts high performance-price ratio changes mutually as voltage and frequency, peripheral circuit is simple, and reliability is high, has reduced the complexity of measuring system, has promoted reliability; The chip AD7656 that employing has high precision and a high slewing rate gathers the A/D conversion of simulated data, and this chip and control system concurrent working have not only guaranteed the real-time of sampled signal, and have significantly improved the calculation and control speed of control system; The utility model can detect each cascade of hot side unit dc voltage rapidly and accurately, and safe interference-free passes to the control system of low potential side.
Description of drawings
Fig. 1 is high pressure H bridge cascade connection type SVG main circuit structure figure;
Fig. 2 is the utility model one example structure block diagram;
Fig. 3 is the LM331 structural drawing;
Fig. 4 is the utility model one embodiment voltage/frequency change-over circuit schematic diagram;
Fig. 5 is the utility model one embodiment frequency/voltage change-over circuit schematic diagram.
Embodiment
As shown in Figure 1, the utility model is applied to the detection of H bridge cascade connection type SVG main circuit cascade unit module dc voltage of 12 cascade unit 25 level of 6Kv high pressure.This SVG adopts wye connection, passes through smoothing reactor
Resistance access electrical network is in parallel with reactive load with being incorporated into the power networks, putting into operation and disconnecting by switch S 1 control system.In figure
Be the AC network electric current,
Be load current,
For injecting the SVG electric current from electrical network.Under condition of high voltage, the dc voltage of H bridge cascade connection type SVG is separate, and the balance of keeping dc voltage has vital meaning to the security ﹠ performance of whole system.
as shown in Figure 2, the cascade unit dc voltage Vdc of hot side obtains proportional small voltage signal that satisfies voltage/frequency module input requirements through bleeder circuit, become frequency electric impulse signal proportional to voltage through the voltage/frequency module converts, converted to after light pulse signal by electricity/light modular converter and pass to the light of low potential side/electric modular converter by multimode optical fiber and convert electric impulse signal to, convert voltage signal to through the frequency/voltage modular converter again, this voltage signal is undertaken finally sending into high pressure H bridge cascade connection type SVG control system after analog to digital conversion by mould/digital-to-analogue piece, to realize corresponding calculation and control.
As shown in Figure 3, LM331 mainly partly is comprised of input comparator, timing comparator, R-S trigger, return-to-zero transistor, bandgap circuit, precision current source circuit, current switch, output protection pipe, output driving tube etc.
As shown in Figure 3, divider resistance is comprised of R1 and R2, to satisfy that the LM331 input voltage requires be the collection voltage signal of 0-10V to voltage on the cascade module dc bus capacitor through forming on resistance R 2 after dividing potential drop, be connected to input pin 7 pin of LM331 after the RC low pass input filter circuit of R3 and C1 composition, the positive voltage of 7 pin inputs makes input comparator output high level make its set to the R-S trigger, Q1 output high level makes the conducting of output driving tube, the Q2 output low level makes the cut-off of return-to-zero transistor, pin 3 output logic low levels.Meanwhile switch is beaten to the right, current source charges to R4, simultaneously because the cut-off of return-to-zero transistor, power supply charges to C2 by R4, during greater than 2Vcc/3, timing comparator output high level resets it to the R-S trigger, the Q1 output low level when C2 two ends charging voltage, the cut-off of output driving tube, pin 3 output logic high level.The transistor turns of return-to-zero simultaneously, C2 discharges rapidly by the return-to-zero transistor, and current switch is beaten to the left side simultaneously, C3 discharges to R4, when the C2 sparking voltage equals input voltage, and input comparator output high level, again make the set of R-S trigger, so repeatedly, form self-sustained oscillation.
By above process analysis procedure analysis as can be known, output frequency
Size is directly affected by R4, R5, R7, C2, so for components accuracy, certain requirement is arranged.And C1 and R3 consist of low-pass filter, can reduce the input voltage disturbing pulse, improve conversion accuracy.
As shown in Figure 3, the differentiating circuit that input pulse forms through C4, R9 is added to the reverse input end of input comparator, and in-phase input end has added about 2Vcc/3 DC voltage through R10, R12 dividing potential drop, and reverse input end has added the Vcc DC voltage.When the input pulse negative edge arrived, the negative pulse that the differentiating circuit that forms through C4, R9 forms was added to reverse input end, when amplitude during greater than Vcc/3, input comparator output high level, make the set of R-S trigger, this moment, current switch was beaten to the right, and current source charges to people R12.And the cut-off of return-to-zero transistor, Vcc charges to C5 by R11, when the C5 both end voltage reached 2Vcc/3, timing comparator output high level made the R-S trigger reset, current switch is beaten to the left side, C6 discharges by R12, the transistor turns of return-to-zero simultaneously, and C6 discharges rapidly, complete charge and discharge process one time, repeat said process when the negative edge pulse comes.
As shown in Figure 4, R1 connects cascade unit dc bus capacitor, and R8 connects electrical to optical converter.
As shown in Figure 5, C4 connects photoelectric commutator, Vout termination mould/number conversion chip.
Frequency/voltage modular converter output voltage is sent into the SVG control system finally by after mould/number conversion chip AD7656 gathers the mould/number conversion of simulated data.
Claims (7)
1. dc voltage isolation detection system that is applicable to high pressure H bridge cascade connection type SVG, it is characterized in that, each cascade of described high pressure H bridge cascade connection type SVG unit dc bus capacitor all is connected with bleeder circuit, voltage/frequency change-over circuit, electrical to optical converter, photoelectric commutator, frequency/voltage change-over circuit, mould/number conversion circuit in turn; Connect by multimode optical fiber between described electrical to optical converter and described photoelectric commutator; The control system of described mould/described high pressure H bridge cascade connection type SVG low potential side of number conversion circuit access.
2. the dc voltage isolation detection system that is applicable to high pressure H bridge cascade connection type SVG according to claim 1, is characterized in that, described bleeder circuit is resistor voltage divider circuit, and described resistor voltage divider circuit comprises the resistance of two series connection.
3. the dc voltage isolation detection system that is applicable to high pressure H bridge cascade connection type SVG according to claim 1, is characterized in that, described voltage/frequency change-over circuit adopts the LM331 chip.
4. the dc voltage isolation detection system that is applicable to high pressure H bridge cascade connection type SVG according to claim 1, is characterized in that, described frequency/voltage change-over circuit adopts the LM331 chip.
5. the dc voltage isolation detection system that is applicable to high pressure H bridge cascade connection type SVG according to claim 1, is characterized in that, described photoelectric commutator model is RX HFBR-2412TZ.
6. the dc voltage isolation detection system that is applicable to high pressure H bridge cascade connection type SVG according to claim 1, is characterized in that, described electrical to optical converter model is TX HFBR-1414TZ.
7. the dc voltage isolation detection system that is applicable to high pressure H bridge cascade connection type SVG according to claim 1, is characterized in that, described mould/number conversion circuit adopts A/D converter AD7656.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320016887 CN203011981U (en) | 2013-01-14 | 2013-01-14 | DC side voltage isolation detection system applied to high voltage H-bridge cascading SVG |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320016887 CN203011981U (en) | 2013-01-14 | 2013-01-14 | DC side voltage isolation detection system applied to high voltage H-bridge cascading SVG |
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| CN203011981U true CN203011981U (en) | 2013-06-19 |
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| CN 201320016887 Expired - Lifetime CN203011981U (en) | 2013-01-14 | 2013-01-14 | DC side voltage isolation detection system applied to high voltage H-bridge cascading SVG |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105444787A (en) * | 2015-11-19 | 2016-03-30 | 国电南瑞科技股份有限公司 | Direct current transmitter with high reliability |
| CN106353582A (en) * | 2016-10-31 | 2017-01-25 | 广西电网有限责任公司电力科学研究院 | High-voltage side direct current voltage sampling module for power electronic transformer of power distribution network |
| CN110716112A (en) * | 2019-11-15 | 2020-01-21 | 国电南京自动化股份有限公司 | Insulation detection method for high-voltage cascaded SVG (static var generator) insulation frame |
| CN114384317A (en) * | 2022-03-24 | 2022-04-22 | 北京合康新能变频技术有限公司 | High-voltage frequency converter and output voltage detection circuit and method thereof |
-
2013
- 2013-01-14 CN CN 201320016887 patent/CN203011981U/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105444787A (en) * | 2015-11-19 | 2016-03-30 | 国电南瑞科技股份有限公司 | Direct current transmitter with high reliability |
| CN106353582A (en) * | 2016-10-31 | 2017-01-25 | 广西电网有限责任公司电力科学研究院 | High-voltage side direct current voltage sampling module for power electronic transformer of power distribution network |
| CN110716112A (en) * | 2019-11-15 | 2020-01-21 | 国电南京自动化股份有限公司 | Insulation detection method for high-voltage cascaded SVG (static var generator) insulation frame |
| CN114384317A (en) * | 2022-03-24 | 2022-04-22 | 北京合康新能变频技术有限公司 | High-voltage frequency converter and output voltage detection circuit and method thereof |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130619 |
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| CX01 | Expiry of patent term |