CN103457239B - The guard method of high frequency uninterrupted power supply short circuit - Google Patents
The guard method of high frequency uninterrupted power supply short circuit Download PDFInfo
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- CN103457239B CN103457239B CN201310388829.9A CN201310388829A CN103457239B CN 103457239 B CN103457239 B CN 103457239B CN 201310388829 A CN201310388829 A CN 201310388829A CN 103457239 B CN103457239 B CN 103457239B
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Abstract
The invention discloses the guard method of a kind of high frequency uninterrupted power supply short circuit; mainly within three civil power cycles, judge whether the condition meeting short circuit; if meet the condition of short circuit; judge it is long-term short circuit or instantaneous short-circuit again; according to different short-circuit-type; process accordingly respectively, thus protection ups power is not compromised.Cost of the present invention is lower, and can distinguish short-circuit type, positions protection.
Description
Technical field
The present invention relates to the guard method of high frequency uninterrupted power supply short circuit, the method is applicable to the online high frequency uninterruptible power system of Three-phase high-power, is also suitable for single-phase high frequency uninterruptible power system.
Background technology
Uninterrupted power supply (ups power) is the visual plant ensureing electric power system reliability, requires that higher occasion generally all needs to be equipped with ups power in power applications.Ups power can be powered to visual plant by battery pack when grid cut-off.While guarantee external equipment power supply safety, the safety of ups power equipment self is also extremely important.Ups power generally needs to provide various protection to ensure inherently safe, comprises overvoltage protection, overheat protector, short-circuit protection etc.Wherein short-circuit protection is the very important safeguard measure of UPS.Due to external disturbance, may there is the short circuit between phase and ground or short circuit between phase and phase in UPS.Very large short circuit current can be produced during short circuit flow between ups system, very large harm is produced to UPS.How to avoid impulse current to damage UPS being the object of short-circuit protection when short circuit.In addition, because the short circuit that may cause the UPS short time is touched in user's false touch, how still to recover normal after the short circuit of this short time is cancelled, namely short circuit is removed obstacles, and is also the thing that short-circuit protection needs to consider.
Tradition UPS many employings hardware circuit does short-circuit protection, and the duration of short circuit that UPS can bear is very short, and is difficult to the long-time short circuit of difference and instantaneous short circuit.In addition, the low reliability of this short-circuit protection that also causes of the aging and anti-interference of hardware circuit reduces.
Summary of the invention
The object of the invention is to solve above-mentioned problems of the prior art, propose a kind of guard method based on the high frequency uninterrupted power supply short circuit of Digital Signal Processing (DSP), the method mainly comprises the following steps:
Step 1. judges whether to meet short circuit condition within three cycles, no, continues monitoring; Perform step 2;
Step 2. puts short circuit mark;
Step 3. is switched to current control mode from voltage mode control;
Step 4. judges in one-period whether contravarianter voltage is greater than short-circuit voltage judging point, is, then perform step 5; No, then perform step 9;
The clear short circuit mark of step 5.;
Step 6. is switched to voltage mode control from current control mode;
It is soft start initial value that step 7. arranges now inverse pressure;
Step 8. inverter voltage soft start;
Step 9. starts to carry out timing to duration of short circuit;
Does step 10. judge that duration of short circuit is more than 5 seconds? no, then return step 4, be, then go to step 11;
Step 11. points out short trouble, shutdown.
Compared with prior art, what the present invention adopted is protection scheme based on software, and therefore, be compared to traditional technical scheme of being carried out short-circuit protection by hardware, cost is lower, and without the need to specialized designs hardware protection circuit.And the protection reliability of the present invention to UPS is higher, flexibility is also higher.Reliably judge that the generation of short circuit event, short-circuit-type, judgement short trouble are set up, or judged that short circuit event is withdrawn from, and can switch between voltage mode control and current control mode flexibly by software.Guard method of the present invention makes short circuit current little, and during short circuit, control output current can within tolerance range at UPS, to protect ups system by the injury of short circuit current.The present invention also has short circuit and to remove obstacles function further.After the short circuit event of short time is sent out, UPS can work on and not shut down after short time short circuit event is cancelled, and improves power supply reliability.
Accompanying drawing explanation
Below, the present invention is described in detail for contrast accompanying drawing and preferred embodiment, wherein:
Fig. 1 is signal wiring relation of the present invention and short circuit schematic diagram;
Fig. 2 is the principle schematic that the present invention controls electric current;
Fig. 3 is the execution schematic flow sheet of the inventive method.
Embodiment
Below in conjunction with drawings and Examples, invention is described in detail.Should be appreciated that to the explanation of specific embodiment only in order to explain the technical scheme that the present invention proposes, and non-limiting the present invention.
Fig. 1 is signal wiring relation in the present invention and short circuit schematic diagram.Three-phase UPS three-phase export structure is connected with load, and with ground wire.The generation of mark a place be short circuit between phase and ground.The generation of mark b place be short circuit between phase and phase.UPS exports and comprises mutually and terra short, phase fault and three-phase shortcircuit.Mutually and terra short comprises the short circuit of R phase and ground, S-phase and ground short circuit, T-phase and ground short circuit three kinds of situations; Phase fault comprises RS phase fault, phase fault and TR phase fault three kinds of situations between ST.The most extreme situation is that three-phase shortcircuit occurs, and namely R, S and T-phase all link together short circuit, and three-phase shortcircuit can be regarded as and is short-circuited between RS, ST and RT all simultaneously.When there is mutually and terra short, this phase inverter voltage is very little and output current is very large.Voltage during generation phase phase short circuit between this two-phase is very little and the output current of this two-phase is all very large.
When being short-circuited, power factor corrector (PFC) part of UPS is substantially unaffected, and what need control is Converting Unit.Inverter is the important component part of UPS uninterrupted power supply, its basic function is the industrial-frequency alternating current of stable output, and make the phase place of output AC point identical with the alternating current phases that electrical network is supplied, complete the switching between inverter output with civil power, can ensure that when load changing circuit normally works, and the stability of output voltage.Working in voltage mode control when UPS normally works, needing when being short-circuited to be operated under current control mode to control output current.During generation mutually and terra short, UPS output current is equal with inductive current, and UPS output voltage is zero.UPS model is equivalent to a proportional amplifier and is connected in series an inductance.When being short-circuited, UPS can equivalent transfer function be:
Then corresponding PI controller can be set to:
Wherein, K
pfor the proportionality coefficient of PI controller, K
ifor the integral coefficient of PI controller, I
reffor given output current reference value, I
lfor sampling inductive current.
Fig. 2 has drawn the transfer function of UPS equivalent model, wherein K
pwmfor the equivalent amplification coefficient of UPS inverter bridge
.given output current reference value I
ref, with sampling inductive current I
lcalculate output variable through PI controller (proportion adjustment and integral adjustment controller) after getting error, this output variable superposes a feedforward duty ratio Feed again and finally obtains Kpwm Duty ratio control amount.The object adding feedforward enhances the stability of control program of the present invention.For the inverter bridge of double-bus structure, feedforward is generally taken as 50% Duty ratio control amount, and such UPS output current may be controlled to zero substantially.For phase fault, need to perform Current Control to the two-phase be short-circuited simultaneously simultaneously.Similarly, for three-phase shortcircuit, then need to perform Current Control to three-phase simultaneously.
Fig. 3 is the control flow schematic diagram of the inventive method.The short-circuit protection method of the high frequency uninterrupted power supply that the present invention proposes, comprising:
Step 1. judges whether to meet short circuit condition within three cycles, no, continues monitoring; Perform step 2;
Step 2. puts short circuit mark;
Step 3. is switched to current control mode from voltage mode control;
Step 4. judges in one-period whether contravarianter voltage is greater than short-circuit voltage judging point, is, then perform step 5; No, then perform step 9;
The clear short circuit mark of step 5.;
Step 6. is switched to voltage mode control from current control mode;
It is soft start initial value that step 7. arranges now inverse pressure;
Step 8. inverter voltage soft start;
Step 9. starts to carry out timing to duration of short circuit;
Does step 10. judge that duration of short circuit is more than 5 seconds? no, then return step 4, be, then go to step 11;
Step 11. points out short trouble, shutdown.
In order to judge that short circuit event occurs reliably, this programme is judging that time lengthening is to 3 civil power cycles, and be such as the civil power of frequency 50Hz, then 1 civil power cycle is 20ms, and 3 civil power cycles are exactly 60ms.If meet the condition of phase fault or mutually and terra short within three cycles, namely output voltage effective value is less than 50V and output current effective value is greater than 50A, then judge that short circuit event occurs.Judging in these three cycles of short circuit, short circuit current all needs by inversion wave limiting function, current peak to be limited in the scope that UPS can bear.After judging that short circuit is set up, immediately from the current control mode shown in normal inverter voltage control mode switch to Fig. 2, now output current is controlled to the less sine wave of an amplitude, to avoid causing damage to ups system.Short circuit event the longest maintenance 5s clock, then thinks long-term short trouble more than 5s, and UPS reports short trouble and shuts down.
If short circuit event disappears within the 5s time be short-circuited, then inverter voltage can revert to a larger effective value in a current mode control.When program detects that inverter voltage effective value is larger after one cycle, then think that short trouble is cancelled, enter short circuit this time and to remove obstacles recovery flow process.Different from judging 3 civil power cycles of short circuit event generation needs, program can judge that short circuit event is cancelled within a civil power cycle, recovers normal power supply to ensure power supply reliability to improve as early as possible.When short circuit recovers, be transformed into voltage mode control from current control mode.Due to inverter voltage when short circuit is cancelled and normal working voltage there is larger pressure reduction, need to take the mode of soft start progressively to improve inverter voltage to avoid producing vibration.To judge that the inverter voltage value set up when short circuit is cancelled is set to the initial value of inverter voltage soft start in this patent, increase inverter voltage amplitude on this basis gradually until rated operational voltage, to reduce to cause larger voltge surge when current control mode is switched to voltage system as far as possible.
Claims (5)
1. a short-circuit protection method for high frequency uninterrupted power supply, described high frequency uninterrupted power supply comprises inverter, it is characterized in that, comprises the steps:
Step 1. judges whether to meet short circuit condition within three cycles, no, continues monitoring; Perform step 2;
Step 2. puts short circuit mark;
Step 3. is switched to current control mode from voltage mode control;
Step 4. judges in one-period whether contravarianter voltage is greater than short-circuit voltage judging point, is, then perform step 5; No, then perform step 9;
The clear short circuit mark of step 5.;
Step 6. is switched to voltage mode control from current control mode;
It is soft start initial value that step 7. arranges now contravarianter voltage;
Step 8. contravarianter voltage soft start;
Step 9. starts to carry out timing to duration of short circuit;
Step 10. judges that whether duration of short circuit is more than 5 seconds,
ifno, then return step 4,
ifthen go to step 11;
Step 11. points out short trouble, shutdown;
In step 3, current control mode controls electric current, its specifically comprise given output current reference value Iref and sampling inductive current IL got error after calculate output variable through PI controller, then this output variable is superposed a feedforward duty ratio Feed again, obtain Kpwm Duty ratio control amount;
The described cycle is the civil power cycle.
2. the method for claim 1, is characterized in that: feedforward duty ratio Feed is 50%.
3. the method for claim 1, is characterized in that: for phase fault, needs to perform current control mode to the two-phase be short-circuited simultaneously simultaneously.
4. the method for claim 1, is characterized in that: for three-phase shortcircuit, needs to perform current control mode to three-phase simultaneously.
5. the method as described in claim 3 or 4, is characterized in that: after step 3 performs, output current is controlled to the less sine wave of an amplitude, to avoid causing damage to high frequency uninterrupted power supply.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201310388829.9A CN103457239B (en) | 2013-08-30 | 2013-08-30 | The guard method of high frequency uninterrupted power supply short circuit |
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| CN201310388829.9A CN103457239B (en) | 2013-08-30 | 2013-08-30 | The guard method of high frequency uninterrupted power supply short circuit |
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| CN103457239A CN103457239A (en) | 2013-12-18 |
| CN103457239B true CN103457239B (en) | 2016-01-20 |
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| CN104914441B (en) * | 2015-01-29 | 2017-06-16 | 上海兰宝传感科技股份有限公司 | A kind of self-identifying output intent of photoelectric sensor |
| CN114039334B (en) * | 2021-11-05 | 2023-12-08 | 上海杰瑞兆新信息科技有限公司 | Converter output short-circuit protection circuit and method without output current sampling |
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| CN102916205A (en) * | 2011-08-05 | 2013-02-06 | 全琎 | Energy-controllable output device for fuel cell and control method |
| CN103095165A (en) * | 2013-01-16 | 2013-05-08 | 武汉新能源接入装备与技术研究院有限公司 | Three-phase inverter parallel-connection control method without output isolation transformer |
| CN103248013A (en) * | 2013-05-10 | 2013-08-14 | 温州大学 | Current transformer current-limiting protection system control device and current-limiting control method thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002186172A (en) * | 2000-12-14 | 2002-06-28 | Kokusan Denki Co Ltd | Inverter power generator and control method in overloaded condition |
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Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1466255A (en) * | 2002-06-29 | 2004-01-07 | 深圳市中兴通讯股份有限公司 | Output overcurrent and short circuit protector for high power contravariant equipment |
| CN1902809A (en) * | 2004-01-09 | 2007-01-24 | 皇家飞利浦电子股份有限公司 | DC/DC converter and decentralized power generation system comprising a DC/DC converter |
| CN102163950A (en) * | 2007-05-30 | 2011-08-24 | 株式会社日立制作所 | Wind power generation system and method of controlling power converter |
| CN102916205A (en) * | 2011-08-05 | 2013-02-06 | 全琎 | Energy-controllable output device for fuel cell and control method |
| CN102830263A (en) * | 2012-08-31 | 2012-12-19 | 惠州三华工业有限公司 | Over-current detection system of inverter circuit and method of over-current detection system |
| CN103095165A (en) * | 2013-01-16 | 2013-05-08 | 武汉新能源接入装备与技术研究院有限公司 | Three-phase inverter parallel-connection control method without output isolation transformer |
| CN103248013A (en) * | 2013-05-10 | 2013-08-14 | 温州大学 | Current transformer current-limiting protection system control device and current-limiting control method thereof |
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| CN103457239A (en) | 2013-12-18 |
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Address after: Shenzhen Nanshan District City, Guangdong province 518000 white pine Luxili Nangang Second Industrial Park 12 Building 1, 2, 5 floor Applicant after: SHENZHEN JINGFUYUAN TECH CO.,LTD. Address before: Shenzhen Nanshan District City, Guangdong province 518000 white pine Luxili Nangang Second Industrial Park 12 Building 1, 2, 5 floor Applicant before: SHENZHEN JINGFUYUAN TECH Co.,Ltd. |
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