CN100435478C - Synchronous detection circuit for frequency changing air conditioner digital voltage lifting PFC circuit - Google Patents
Synchronous detection circuit for frequency changing air conditioner digital voltage lifting PFC circuit Download PDFInfo
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- CN100435478C CN100435478C CNB2006101469869A CN200610146986A CN100435478C CN 100435478 C CN100435478 C CN 100435478C CN B2006101469869 A CNB2006101469869 A CN B2006101469869A CN 200610146986 A CN200610146986 A CN 200610146986A CN 100435478 C CN100435478 C CN 100435478C
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- air conditioner
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- comparator
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Abstract
This invention relates to a synchronous detection circuit of a conversion air-condition digit boosting PFC circuit including a comparing circuit, the positive input end of which is connected with a reference level, the negative input end is connected with a voltage sampling circuit linked to a rectifier circuit output end, a serial circuit of a resistor and a diode is connected between the output end of the comparator and a reference end, four diodes bridged in the rectifier circuit are parallel to a capacitor separately and the output end of the circuit is parallel to another resistor, which weakens the HF pulse interference signal overlapped on the output voltage of the rectifier circuit from a reverse circuit, and the serial resistors and diodes of the feedback loop of the comparator increases the bandwidth of the slag ring response to ensure that synchronous signals have enough pulse width.
Description
Technical field
The present invention relates to power electronic technology, specifically is a kind of sync detection circuit that is applied in the frequency changing air conditioner digital voltage lifting PFC circuit.
Background technology
In recent years, along with improving constantly of living standard and awareness of saving energy, convertible frequency air-conditioner obtains popularizing rapidly.Usually only be furnished with single-phase 220 volts of power supplys because domestic common merchant lives building, convertible frequency air-conditioner faces following two problems in actual applications.The first, when the input circuit of frequency converter only was made of single-phase full wave diode rectifier bridge and flat wave capacitor, input current waveform was pulse type, and total percent harmonic distortion surpasses 100%, and electrical network is caused very big harmonic pollution.The second, the DC bus-bar voltage fluctuation that obtains by the single-phase full wave rectification is big, and the mean value of voltage reduces significantly during heavy duty, causes compressor current to increase sharply.In order to prevent overcurrent, maximum running frequency that can only the limit compression machine causes the ability of compressor to be not in full use.
At rectification bridge output end the voltage lifting PFC circuit is set and solves harmonic pollution and direct voltage decline problem simultaneously.Frequency converter one example of convertible frequency air-conditioner is seen Fig. 1 at present, mainly comprise rectification circuit, voltage lifting PFC circuit and inverter circuit etc., system works under microcontroller MCU control, also has parts such as synchronous detecting, input current detection, PFC driving, direct voltage detection, PWM driving, output current detection.Rectification circuit adopts diode rectifier bridge, and single-phase 220V alternating current is carried out full-wave rectification; The voltage lifting PFC circuit adopts conventional Boost circuit structure, and its effect is by the control to switching device S, makes direct voltage V
DcKeep stable, make the input current i of frequency converter simultaneously
SHave and the synchronous sinusoidal waveform of supply voltage.
The phase place of supply voltage is a requisite information in the PFC control, can obtain with diverse ways, and wherein the simplest method is to utilize comparison circuit shown in Figure 2 to detect supply voltage V
SZero crossing.Supply voltage enters comparator input terminal through after the dividing potential drop, when being higher than reference level V
COMThe time, the comparator output low level; On the contrary, when being lower than reference level, comparator output high level.Control chip MCU passes through comparator output signal V
SYNThe processing of rising edge obtains the synchronizing signal of supply voltage, forms the same-phase sinusoidal reference waveform that not influenced by voltage waveform with this.But sync detection circuit need use isolating device to make input power supply and MCU keep insulation.In view of MCU is with the N of dc bus signal ground very, so adopt directly detection rectifier bridge output voltage V
RGenerate the method for synchronizing signal, do not need to carry out electrical isolation between sync detection circuit and the MCU, cost reduces.In ideal conditions, the waveform of zero-crossing detection circuit as shown in Figure 3, wherein Fig. 3 a represents to detect the waveform of rectifier bridge input terminal voltage, Fig. 3 b represents to detect the waveform of rectification bridge output end voltage.
When the synchronous detecting of frequency changing air conditioner digital voltage lifting PFC circuit adopted zero-crossing detection circuit shown in Figure 2, main circuit connection as shown in Figure 4.With reference to Fig. 5 rectification bridge output end voltage and synchronization waveform figure, the waveform measured result when pfc circuit and inverter circuit off-duty is shown in Fig. 5 (a), and Fig. 5 (a) middle and upper part is the rectification bridge output end voltage waveform, with the perfect condition basically identical.But when inverter circuit moved, measured waveform was shown in Fig. 5 (b).Because rectifier bridge output voltage v
RWaveform on the high-frequency impulse that superposeed, the narrower in width of the high level output of comparator, perhaps one connects and several burst pulses occur, can't produce the efficient synchronization signal.Because the step-up ratio of the voltage lifting PFC circuit of convertible frequency air-conditioner is low, pfc circuit should not move during underloading, has only when inverter circuit operation and load acquire a certain degree, and could start pfc circuit.Therefore, must solve the problem of above-mentioned synchronizing signal vibration.
Summary of the invention
The problems referred to above in view of the prior art existence, the invention provides a kind of sync detection circuit of improved frequency changing air conditioner digital voltage lifting PFC circuit, by shunt capacitance on each diode of rectifier bridge, between positive and negative dc bus and measure such as connecting resistance, weakening is disturbed from the high-frequency impulse of inverter circuit, obtains the synchronization pulse that system needs.
The sync detection circuit of the frequency changing air conditioner digital voltage lifting PFC circuit that the present invention proposes is the improvement design of prior art.It comprises a comparison circuit, the positive input termination reference level of described comparison circuit, the comparator negative input end is connected with the voltage sample circuit that is connected to rectification circuit output end, be connected resistance and diode series circuit between comparator output terminal and the reference edge, four of bridge joint rectifier diode difference electric capacity in parallel in the rectification circuit, rectification circuit output end also and connect another resistance, be used to weaken the high-frequency impulse interference signal on the Output Voltage in Rectified Circuits that is superimposed on, obtain the synchronization pulse that system needs from inverter circuit.
Sync detection circuit technical conceive novelty of the present invention, circuit structure is simple, and each diode difference shunt capacitance at rectifier bridge inserts resistance between positive and negative dc bus, weakened greatly to be superimposed on high-frequency impulse interference signal on the Output Voltage in Rectified Circuits; Between comparator output terminal and reference edge, be connected resistance and diode serial Feedback circuit, the bandwidth of the ring response that stagnates is increased, guarantee that synchronizing signal has enough pulse durations.
The present invention is through test, and the high-frequency impulse of rectification bridge output end voltage significantly reduces, and the synchronization waveform of output is good, and system is stable.
Description of drawings
Fig. 1 is the frequency converter one example theory diagram of traditional frequency conversion air-conditioning;
The zero-crossing detection circuit figure of Fig. 2 for adopting among Fig. 1;
Fig. 3 is the waveform of zero-crossing detection circuit ideally;
Fig. 4 is the system's main circuit diagram that contains Fig. 2 zero-crossing detection circuit;
Fig. 5 is rectification bridge output end voltage and synchronization waveform figure;
Fig. 6 is for adopting system's main circuit diagram of circuit of the present invention.
Embodiment
The present invention is further described below in conjunction with accompanying drawing.
With reference to Fig. 6, the sync detection circuit of frequency changing air conditioner digital voltage lifting PFC circuit of the present invention comprises a comparison circuit, the positive input termination reference level V of described comparison circuit
COM, this reference level passes through resistance R by+5V power supply
2, R
3Dividing potential drop obtains, and rectification circuit output end connects by resistance R
2, R
3The voltage sample circuit that is composed in series, resistance R
2, R
3Common port is received the comparator negative input end, is connected resistance R between comparator output terminal and reference edge
6With diode D
5Series circuit, diode D
5Negative terminal connect the positive input terminal of comparison circuit; Four of bridge joint rectifier diode D in the rectification circuit
1～D
4Difference shunt capacitance C
1～C
4, rectification circuit output end also and connect a resistance R
1, be used to weaken the high-frequency impulse interference signal on the Output Voltage in Rectified Circuits that is superimposed on from inverter circuit; Resistance R wherein
7Output pull-up resistor for comparison circuit.
From Fig. 6 as seen, the present invention has done following 2 improvement to traditional circuit:
1. at the diode D of rectifier bridge
1～D
4Last shunt capacitance C respectively
1～C
4, between positive and negative dc bus, insert resistance R
1, weaken the interference of inverter circuit.
The waveform experimental result of Fig. 5 (b) shows, is not adding above-mentioned capacitor C
1～C
4And resistance R
1Situation under, when inverter circuit moves, rectifier bridge output v
RWaveform on the high-frequency impulse that superposeed.Its reason is flat wave capacitor C
5On metastable high direct voltage is arranged, make each diode most of the time be in reverse blocking state, and in fact the reverse blocking dynamic characteristic of diode is subjected to the influence of its junction capacitance.When inverter circuit operation earlier, high-frequency pulse current appears on the dc bus, cause D
1～D
4And D
6The reverse voltage of (in pfc circuit) is in the dynamic change state all the time, constantly distribute the reverse voltage total according to separately junction capacitance and line parameter circuit value with balance, cause the voltage of rectification bridge output end to contain high-frequency impulse, sync detection circuit can't produce the efficient synchronization signal.
The present invention is by shunt capacitance C on each diode of rectifier bridge
1～C
4, the ratio of change equivalent junction capacitance makes D
6Bear bigger pulse voltage, thereby reduce the pulse composition of rectification bridge output end voltage, the assurance synchronizing signal is not vibrated; Newly-increased resistance R
1Be C
1～C
4Discharge channel is provided, makes v
RMinimum value near zero, thereby guarantee that per half power supply cycle all produces lock-out pulse, and make the synchronizing signal rising edge consistent as far as possible with the supply voltage zero crossing.
Through experiment repeatedly, shunt capacitance C on each diode in the rectification circuit
1～C
4Capacity be 1100～4700pF, rectification circuit output end parallel resistance R
1Be 20～60k Ω.
2. between comparator output terminal and reference edge, be connected resistance R
6With diode D
5Series circuit particularly increases diode D
5, the bandwidth of the ring response that stagnates is increased, guarantee synchronizing signal V
SYNHave enough pulse durations.
Between comparator reference end and output, only insert resistance R
6, just can produce the ring response characteristic that stagnates.The ring response characteristic that stagnates can be eliminated the flutter phenomenon of synchronizing signal, has also determined the width that synchronizing signal is dashed.
There is not diode D
5The time, synchronizing signal V
SYNBecome the condition of high level by low level:
Wherein, V
LHBe synchronizing signal V
SYNThe input voltage of rising edge correspondence;
Synchronizing signal V
SYNBecome low level condition by high level:
Wherein, V
HLBe synchronizing signal V
SYNThe input voltage of trailing edge correspondence;
For the rising edge that makes synchronizing signal consistent with the supply voltage zero crossing, the V of formula (1)
LHShould exhaust the little value of possibility; Content 1 of the present invention has reduced the pulse composition of rectification bridge output end voltage, but can not eliminate fully, for the pulse that makes synchronizing signal has enough width, and the V of formula (2)
HLShould exhaust the big value of possibility.But, in the allowed band of comparator input signal, and guarantee the high level of synchronizing signal can satisfy the requirement of MCU (＞4V), be difficult to selected suitable R according to formula (1), (2)
2～R
7
In order to address the above problem, increase by one and resistance R
6Diode in series D
5, V
SYNIt is still constant to become low level condition by high level, but is become by the condition that low level becomes high level
According to formula (2), (3), select by reasonable parameter, can realize V
LH≈ 15V, V
HL≈ 200V.
Embodiment: apply the present invention in the multi-joint machine DC frequency converting air-conditioner special converter, adopt with a slice MCU and implement PFC and inversion control.The sinusoidal wave control of Speedless sensor, switching frequency 5kHz, peak power output 4.5kW are adopted in inversion.Pfc circuit adopts dead beat control, switching frequency 20kHz.Wherein, the parameter of sync detection circuit is selected as follows:
Comparator: LM311H or CA311 chip
Each diode shunt capacitance: C of rectifier bridge
1=C
2=C
3=C
4=2200pF
The parallel resistance of rectification bridge output end: R
1=47k Ω
All the other each resistance: R
2=300k Ω, R
3=4.7k Ω, R
4=100k Ω, R
5=4.7k Ω, R
6=1.0k Ω, R
7=1.0k Ω
With resistance R
6Diode in series D
5: 1N4148 etc.
Can get V according to above-mentioned formula (2), (3)
LH=15V, V
HL=229V.Fig. 5 (c) is a measured result, and the high-frequency impulse of rectification bridge output end voltage significantly reduces, and synchronization waveform is good, and system is stable.
Claims (5)
1, a kind of sync detection circuit of frequency changing air conditioner digital voltage lifting PFC circuit, comprise a comparison circuit that contains comparator, it is characterized in that: the positive input termination reference level of described comparator, the comparator negative input end is connected with the voltage sample circuit that is connected to rectification circuit output end, be connected resistance and diode series circuit between comparator output terminal and the positive input terminal, four of bridge joint rectifier diode electric capacity respectively in parallel in the rectification circuit, rectification circuit output end also and connect another resistance is used to weaken the high-frequency impulse interference signal on the Output Voltage in Rectified Circuits that is superimposed on from inverter circuit.
2, according to the sync detection circuit of the frequency changing air conditioner digital voltage lifting PFC circuit of claim 1, it is characterized in that: described comparison circuit adopts LM311H or CA311 chip.
3, according to the sync detection circuit of the frequency changing air conditioner digital voltage lifting PFC circuit of claim 1, it is characterized in that: 1100～4700pF electric capacity in parallel on each diode of described rectification circuit, rectification circuit output end also connects 20～60k Ω resistance.
4, according to the sync detection circuit of the frequency changing air conditioner digital voltage lifting PFC circuit of claim 1, it is characterized in that: 1100～4700pF electric capacity in parallel on each diode of described rectification circuit.
5, according to the sync detection circuit of the frequency changing air conditioner digital voltage lifting PFC circuit of claim 1, it is characterized in that: described rectification circuit output end also connects 20～60k Ω resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006101469869A CN100435478C (en) | 2006-09-08 | 2006-11-28 | Synchronous detection circuit for frequency changing air conditioner digital voltage lifting PFC circuit |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200610062546.5 | 2006-09-08 | ||
| CN200610062546 | 2006-09-08 | ||
| CNB2006101469869A CN100435478C (en) | 2006-09-08 | 2006-11-28 | Synchronous detection circuit for frequency changing air conditioner digital voltage lifting PFC circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1988370A CN1988370A (en) | 2007-06-27 |
| CN100435478C true CN100435478C (en) | 2008-11-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2006101469869A Expired - Fee Related CN100435478C (en) | 2006-09-08 | 2006-11-28 | Synchronous detection circuit for frequency changing air conditioner digital voltage lifting PFC circuit |
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Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090092502A1 (en) * | 2007-10-08 | 2009-04-09 | Emerson Climate Technologies, Inc. | Compressor having a power factor correction system and method |
| CN101418983B (en) * | 2007-10-23 | 2011-03-09 | 海尔集团公司 | Power supply system for air conditioner and power supply method |
| CN103516228B (en) * | 2012-06-18 | 2016-10-05 | 珠海格力电器股份有限公司 | The power conversion modules of transducer air conditioning |
| CN104953917B (en) * | 2015-06-30 | 2017-07-07 | 广东美的制冷设备有限公司 | Input current open loop amplitude limit method and system during air-conditioning system grid voltage sags |
| CN110429898B (en) * | 2019-08-15 | 2021-11-30 | 海信（山东）空调有限公司 | Control method and device of frequency conversion equipment and frequency conversion equipment |
| CN113852320B (en) * | 2021-08-20 | 2024-04-02 | 杭州先途电子有限公司 | Motor control circuit and variable frequency controller |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2178956Y (en) * | 1993-12-27 | 1994-10-05 | 董方秘 | Safety device for electrical equipment of household |
| CN2295285Y (en) * | 1997-02-03 | 1998-10-21 | 王永生 | Random power-less compensator |
| JP2003111423A (en) * | 2001-09-28 | 2003-04-11 | Matsushita Electric Ind Co Ltd | Power source unit |
-
2006
- 2006-11-28 CN CNB2006101469869A patent/CN100435478C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2178956Y (en) * | 1993-12-27 | 1994-10-05 | 董方秘 | Safety device for electrical equipment of household |
| CN2295285Y (en) * | 1997-02-03 | 1998-10-21 | 王永生 | Random power-less compensator |
| JP2003111423A (en) * | 2001-09-28 | 2003-04-11 | Matsushita Electric Ind Co Ltd | Power source unit |
Non-Patent Citations (2)
| Title |
|---|
| 一种新型高效电容型非线性阻抗变换整流电路. 侯云海，关巍，林哲.长春工业大学学报，第27卷第1期. 2006 |
| 一种新型高效电容型非线性阻抗变换整流电路. 侯云海，关巍，林哲.长春工业大学学报，第27卷第1期. 2006 * |
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|---|---|
| CN1988370A (en) | 2007-06-27 |
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Granted publication date: 20081119 Termination date: 20121128 |