CN103713558A - Loop gain scanning method used for digital control circuit - Google Patents
Loop gain scanning method used for digital control circuit Download PDFInfo
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- CN103713558A CN103713558A CN201310748032.5A CN201310748032A CN103713558A CN 103713558 A CN103713558 A CN 103713558A CN 201310748032 A CN201310748032 A CN 201310748032A CN 103713558 A CN103713558 A CN 103713558A
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Abstract
The invention discloses a loop gain scanning method used for a digital control circuit. Through a frequency spectrum scanner, a nearly-true system transfer function is obtained, but the method can be implemented under the condition that the frequency spectrum scanner exists in a laboratory, and certain limitation exists. The loop gain scanning method used for the digital control circuit is characterized in that by adjusting the duty ratio D to control a switch tube, the loop gain frequency band range is determined; the scanning step length is determined and namely, the difference between two adjacent scanning frequencies is determined; the amplitude value of disturbing signals is determined; loop gain points are calculated, and then a line is drawn according to point values; according to the influences of the duty ratio of each interference signal on output signals, the variable quantity of the output signals is sampled. With the method, amplitude-frequency characteristics and phase frequency characteristics can be obtained under the condition that no scanner exists.
Description
Technical field
the present invention relates to a kind of loop gain scan method, be specifically related to a kind of loop gain scan method for digital control circuit.
Background technology
The closed-loop control that in photovoltaic system, inverter is taked, need to understand system transter, it is the impact that the disturbing signal of each wavelength coverage can cause output, comprise the impact of amplitude and phase place, then according to the requirement to system output characteristics, design qualified controller, thereby guarantee that power supply obtains stable output and good performance.In the design phase of principle; because designer understands the principle of circuit; can release by theory the open-loop transfer function of circuit; thereby design theoretical controller parameter; but in side circuit; the time delay causing due to additional various defencive function circuit or due to digital control realization or non-linear, all can cause the transport function of side circuit and the result that theoretical transport function differs greatly.Normally adopt spectrum scan instrument to obtain approaching real ssystem transfer function, spectrum scan instrument is actually the undesired signal that adds characteristic frequency section in driving signal, then impact on output according to it, obtain amplitude versus frequency characte and the phase-frequency characteristic of system, but this method needs laboratory to have spectrum scan instrument to implement, therefore there is certain limitation.
Summary of the invention
The object of this invention is to provide a kind of loop gain scan method for digital control circuit that obtains system loop-gain characteristic in without spectrum scan instrument situation.
For solving the problems of the technologies described above, technical scheme of the present invention is: a kind of loop gain scan method for digital control circuit, and its special feature is: comprise the following steps:
(1) by regulating dutycycle D the control of switching tube to be determined to the band limits of loop gain;
(2) determine the step-length of scanning, the frequency of adjacent two scannings is poor;
(3) amplitude of deterministic disturbances signal: the undesired signal of definite band limits in modulating wave the inside adds step (1), this signal determined by frequency and amplitude, the size of its amplitude guarantees can not affect the normal work of quiescent point;
(4) calculate loop gain point, then according to point value, retouch line; The impact bringing to output signal according to the dutycycle of each undesired signal, the variable quantity of sampled output signal, according to Logarithmic calculation formula:
, calculate the gain of each Frequency point, can retouch out loop gain curve.
The band limits of determining loop gain in described step (1) is that 0Hz arrives
between Hz.
Compared with prior art, the present invention has following beneficial effect: the present invention passes through in output signal y (s) and the amplitude versus frequency characte relation of input signal u (s) in one section of frequency spectrum, the undesired signal of a series of frequency ranges that can superpose on input signal, then sampled output signal, by formula, calculate the Spectrum Relationship of output signal to input signal, in the situation that there is no scanner, by method of the present invention, just can not obtain amplitude versus frequency characte and phase-frequency characteristic.
Accompanying drawing explanation
Fig. 1 is the schematic diagram that in the inventive method, step 1 modulating wave and carrier wave ratio obtain dutycycle D;
Fig. 2 is the schematic diagram of step 2 in the inventive method;
Fig. 3 is step 3 schematic diagram in the inventive method;
Fig. 4 is the schematic diagram of step 4 in the inventive method.
Embodiment
Below in conjunction with embodiment, the present invention will be described in detail.
A loop gain scan method for digital control circuit, comprises the following steps:
(1) first, determine the band limits want the loop gain that obtains: referring to Fig. 2, general because be by regulating dutycycle to go to realize to the control of switching tube to the control of system, so switching frequency
near, or even switching frequency
the loop gain of half and above frequency range is all otiose; Therefore definite frequency range that need to scan loop gain is that 0Hz arrives
between Hz;
(2) determine the step-length of scanning, the frequency of adjacent two scannings is poor, in Fig. 2
.This does not generally have strict value, step-length is little, and whole scanning process can be slow, scanning process that step-length is large can be than comparatively fast, and just as described point line, point is more, line is more accurate, but the calculative point of possibility is more, and speed is slower, conventionally in photovoltaic DC-to-AC converter, considers that mains frequency is 50Hz, in order to take into account accuracy and runtime, step-length that can scanning is set to 10Hz;
(3) amplitude of deterministic disturbances signal: the undesired signal of definite band limits in modulating wave the inside adds step (1), see Fig. 3, this undesired signal is determined by frequency and amplitude, the frequency of each undesired signal can be obtained by above-mentioned 2 steps, the size of its amplitude should guarantee can not affect the normal work of quiescent point, for example the dutycycle of quiescent point is 0.5, and the dutycycle disturbance size that the disturbing signal adding so causes should be no more than 0.01, in figure
should be much smaller than D;
(4) calculate loop gain point, then according to point value, retouch line: the impact bringing to output signal according to the dutycycle of each undesired signal, the variable quantity of sampled output signal, according to Logarithmic calculation formula,
, calculate the gain of each Frequency point, can retouch out at 0Hz and arrive
loop gain curve, i.e. Bode diagram, referring to Fig. 4.
Claims (2)
1. for a loop gain scan method for digital control circuit, it is characterized in that: comprise the following steps:
(1) by regulating dutycycle D the control of switching tube to be determined to the band limits of loop gain;
(2) determine the step-length of scanning, the frequency of adjacent two scannings is poor;
(3) amplitude of deterministic disturbances signal: the undesired signal of definite band limits in modulating wave the inside adds step (1), this signal determined by frequency and amplitude, the size of its amplitude guarantees can not affect the normal work of quiescent point;
(4) calculate loop gain point, then according to point value, retouch line; The impact bringing to output signal according to the dutycycle of each undesired signal, the variable quantity of sampled output signal, according to Logarithmic calculation formula:
, calculate the gain of each Frequency point, can retouch out loop gain curve.
2. according to a kind of loop gain scan method for digital control circuit described in claim 1, it is characterized in that: the band limits of determining loop gain in described step (1) is that 0Hz arrives
between Hz.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310748032.5A CN103713558B (en) | 2013-12-31 | 2013-12-31 | A kind of loop gain scan method for digital control circuit |
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|---|---|---|---|
| CN201310748032.5A CN103713558B (en) | 2013-12-31 | 2013-12-31 | A kind of loop gain scan method for digital control circuit |
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| CN103713558A true CN103713558A (en) | 2014-04-09 |
| CN103713558B CN103713558B (en) | 2016-06-15 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116930808A (en) * | 2023-06-26 | 2023-10-24 | 广州致远仪器有限公司 | Stability testing method, device and equipment for power loop and storage medium |
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| CN101841331A (en) * | 2009-03-19 | 2010-09-22 | 谌君 | Method for designing passive filter of charge pump phase-locked loop (CPPLL) |
| US20110298410A1 (en) * | 2010-06-03 | 2011-12-08 | On Semiconductor Trading, Ltd. | Loop gain adjusting circuit |
| CN102426416A (en) * | 2011-09-05 | 2012-04-25 | 广东电网公司电力科学研究院 | Method and device for identifying frequency domain amplitude characteristic of control object |
| CN103051177A (en) * | 2012-12-20 | 2013-04-17 | 矽力杰半导体技术(杭州)有限公司 | Quick response control circuit and control method thereof |
-
2013
- 2013-12-31 CN CN201310748032.5A patent/CN103713558B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101841331A (en) * | 2009-03-19 | 2010-09-22 | 谌君 | Method for designing passive filter of charge pump phase-locked loop (CPPLL) |
| US20110298410A1 (en) * | 2010-06-03 | 2011-12-08 | On Semiconductor Trading, Ltd. | Loop gain adjusting circuit |
| CN102426416A (en) * | 2011-09-05 | 2012-04-25 | 广东电网公司电力科学研究院 | Method and device for identifying frequency domain amplitude characteristic of control object |
| CN103051177A (en) * | 2012-12-20 | 2013-04-17 | 矽力杰半导体技术(杭州)有限公司 | Quick response control circuit and control method thereof |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116930808A (en) * | 2023-06-26 | 2023-10-24 | 广州致远仪器有限公司 | Stability testing method, device and equipment for power loop and storage medium |
| CN116930808B (en) * | 2023-06-26 | 2024-01-23 | 广州致远仪器有限公司 | Stability testing method, device and equipment for power loop and storage medium |
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| CN103713558B (en) | 2016-06-15 |
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Address after: 710021 export processing zone, No. twelve, 1 road, Fengcheng, Shaanxi, Xi'an Patentee after: Longteng Semiconductor Co.,Ltd. Address before: 710021 export processing zone, No. twelve, 1 road, Fengcheng, Shaanxi, Xi'an Patentee before: LONTEN SEMICONDUCTOR Co.,Ltd. Address after: 710021 export processing zone, No. twelve, 1 road, Fengcheng, Shaanxi, Xi'an Patentee after: LONTEN SEMICONDUCTOR Co.,Ltd. Address before: 710021 export processing zone, No. twelve, 1 road, Fengcheng, Shaanxi, Xi'an Patentee before: XI'AN LONTEN RENEWABLE ENERGY TECHNOLOGY Inc. |
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