CN101795087A - Inductive load commutation method - Google Patents
Inductive load commutation method Download PDFInfo
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- CN101795087A CN101795087A CN 201010138622 CN201010138622A CN101795087A CN 101795087 A CN101795087 A CN 101795087A CN 201010138622 CN201010138622 CN 201010138622 CN 201010138622 A CN201010138622 A CN 201010138622A CN 101795087 A CN101795087 A CN 101795087A
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Abstract
The invention relates to an inductive load commutation method, and the method comprises the following steps: setting two reverse branches for supplying power to an inductive load alternately; carrying out real-time monitoring on the current of the load; and freewheeling the load whenever one branch is turned from the on-state to the off-state, and further giving a control command for turning the other branch to the on-state after monitoring that the freewheeling current is zero. The method can indirectly sense the inductance of the load and the release situation of stored energy of the load by measuring the freewheeling current in a current loop of the load, thereby being automatically applicable to the loads with different inductances according to the time which needs to switch the current direction and improving the efficiency.
Description
Technical field
The present invention relates to electricity field, relate in particular to a kind of method that need need carry out sense of current switching to inductive load.
Background technology
Electric current is called the change of current from the process that another branch road of Zhi Luxiang shifts.
When inductive load is carried out the change of current, because the inductive load electric current can not suddenly change, must stagnate a period of time (time of afterflow), the energy storage of waiting for this load discharges fully just can carry out reciprocal electric current output.
Elements such as employing controlled tr tube carry out the change of current as control device, are common modes.For elements such as the requirement of load running and protection switch pipes, usual way is: by table look-up, handbook or rule of thumb, set fixing time of afterflow to control device.Yet, different loads, needed time of afterflow is not quite similar, even difference is very big; So during the design time of afterflow, often the longest time of afterflow is made as unified time of afterflow, this just causes in most cases, given time of afterflow has caused the reduction of efficient greater than the time of afterflow of reality.
Employing Fig. 1 further specifies, and before the moment, load current continues to increase under the reverse voltage effect at t1; At t1 constantly, remove reverse voltage, electric current begins afterflow, and is reduced to zero gradually, is t2 constantly to zero; T3 adds forward voltage constantly, and electric current begins forward to be increased.As seen, the time of load afterflow is Td0=t2-t1, owing to do not know the inductance value and the energy storage situation of inductance, the fixedly time of afterflow that is provided with needs certain allowance, and as shown in Figure 1, the fixedly time of afterflow of setting is Td, Td=t3-t1, Td〉Td0, so the time of afterflow Td that is provided with is longer than actual time of afterflow, so this control efficiency is very low.
In production practices, when the load object of certain class control device may have the inductance value that differs greatly, under the situation that can not predict load inductance amount, maximum storage energy, fixedly the time of afterflow design of length in addition may make control device design, produce and can't carry out.
Summary of the invention
Order of the present invention is, a kind of inductance value and energy storage that can the self adaptation inductive load be provided, and adjusts the efficient change of current method of time of afterflow.
For achieving the above object, technical program of the present invention lies in:
A is provided with two reverse branch roads and alternately powers to inductive load;
B carries out real-time monitoring to load current;
C is whenever a route on-state transfers off-state to, the load afterflow, to be monitored be zero to freewheel current after, provide control command again, make another branch road transfer on-state to.
The on-state of described branch road and off-state are to be realized with turn-offing by the conducting of the controlled tr tube on the branch road; Controlled switching tube, its conducting and shutoff are subjected to the control of gate signal.And reverse parallel connection has fly-wheel diode on the controlled tr tube.
Owing to adopted current detecting, by the freewheel current in the sensing lead current circuit, the size of perception load inductance and load energy storage release conditions indirectly; When freewheel current is zero, in time change on off state, carry out the change of current, make control continuously, compactness has improved efficient.
Description of drawings
Fig. 1 is that prior art adopts the fixedly current/voltage variation schematic diagram of the inductive load of time of afterflow;
Fig. 2 is the current/voltage schematic diagram of the embodiment of the invention one;
Fig. 3 is the current/voltage schematic diagram of the embodiment of the invention two;
Fig. 4 is the circuit diagram of H bridge inverter circuit band inductive load;
Fig. 5 is the comparison schematic diagram of prior art, embodiment one, embodiment two;
Fig. 6 is the schematic diagram that is used to detect the comparison expression current detection circuit of electric current.
Embodiment
The present invention is that example further specifies with grinding machine magnechuck controller.Grinding machine magnechuck controller, controlling object are all kinds of magnechucks.Magnechuck is an electromagnetic switching device, and in the course of work, controller control magnechuck magnetizes and demagnetizes operation.In the circuit, magnechuck is an inductive load, and the magnechuck inductance value of various models has great difference.
The direct current reversing damped method is adopted in the demagnetization operation of grinding machine magnechuck, by continuous change sense of current, makes the electric current by loading coil decay to zero gradually, thereby demagnetizes.For reliable demagnetization, decay to zero except guaranteeing each current of commutation, also will make the commutation number of times necessary abundant, and each attenuation amplitude is as far as possible little.Therefore, in demagnetization operation, controller exports that one group of duty ratio progressively diminishes, the square wave sequence of positive and negative alternating polarity, until the duty ratio of square wave near zero.Fig. 1 is the current-voltage waveform figure that adopts the inductance coil of prior art.Among the figure, duty ratio constantly reduces, and near zero, so each time of afterflow is also shorter and shorter, but each time of afterflow all is Td, has caused the very big reduction of efficient until current attenuation.
Embodiment one
Fig. 4 is the main circuit of demagnetizing apparatus, has adopted the H bridge inverter circuit, and two reverse branch roads are respectively by two switching tube Q1, Q4 and two switching tube Q2, and Q3 forms, two complementary conductings of branch road; Inductance L is a loading coil; Sampling resistor R connects with loading coil L, and voltage on this resistance R of sampling just can obtain the freewheel current value of sampling divided by the resistance R resistance.By controlling the turn-on and turn-off of four switching tubes, the ever-reduced ac square wave of output duty cycle, four switching tube Q1, Q2, Q3, Q4 last inverse parallel four diode D1, D2, D3, D4 respectively as fly-wheel diode, provide the afterflow path of electric current.Close at branch switch pipe and to have no progeny, load current can not suddenly change, and the fly-wheel diode by another branch road carries out afterflow, is reduced to zero up to electric current.
This embodiment adopted the mode of zero balancing, the zero crossing of monitoring current, in case electric current is zero, in conjunction with the state information of switching tube, the control switch pipe carries out change of current operation.The current-voltage waveform of this embodiment as shown in Figure 2, switching tube Q1 when initial, Q4 conducting; According to the duty ratio of initial setting, t1 controls two switching tube Q1 of a branch road constantly, and Q4 turn-offs, owing to lose power supply, freewheel current constantly reduces, and in the t2 moment, afterflow finishes, and electric current drops to zero, actuating switch pipe Q2 immediately, Q3, then load voltage and electric current are all reverse, and electric current begins to increase.As can be seen, present time of afterflow equals actual time of afterflow Td0.Because duty ratio constantly reduces, time of afterflow Td0 also constantly reduces.In the present embodiment, accurately detect the zero crossing of freewheel current, can adopt single-chip microcomputer or chip with strong A/D function, finish moment in afterflow and provide the switching tube triggering signal immediately, realize the change of current, it is the highest that efficient reaches.
Embodiment two
Embodiment two only is with the difference of embodiment one: embodiment two chooses the approximation of a very little generating positive and negative voltage value as zero potential, and provides a very short time-delay when electric current reaches this value detecting.Because the precision problem of measuring, current zero-crossing point may and be not easy to determine.So when measuring a reference potential point is set, make reference potential point very near zero potential, come the analogue zero current potential with reference potential point.In order to reach this purpose, embodiment two has adopted a kind of comparison expression current detection circuit that is used to detect electric current, and its circuit theory diagrams as shown in Figure 6.Amplifier U1A and its peripheral circuit are formed sign-changing amplifier, and amplifier U1B and amplifier U1C and its peripheral circuit are formed comparator; Four R7, R4, R6, R8 are connected in series between positive supply and the negative supply successively, for comparator provides voltage reference and reference potential; The resistance of resistance R 7 and resistance R 8 equates that the resistance of resistance R 4 and resistance R 6 equates, ground connection between resistance R 4 and the resistance R 6.The reverse input end R of amplifier U1B is connected between resistance R 7 and the resistance R 4, the positive input R ' of amplifier U1C is connected between resistance R 6 and the resistance R 8, the output T that the positive input of amplifier U1B and the reverse input end of amplifier U1C link together and be connected amplifier U1A.Amplifier U1B forms homophase input simple gate limit voltage comparator, and amplifier U1B forms anti-phase input simple gate limit voltage comparator.Their reference point of potential is respectively R point and R ' point, R point voltage and R ' point voltage equal and opposite in direction, and direction is opposite, is respectively the generating positive and negative voltage reference value.When the current signal of sampling is introduced from the IN terminal, through amplifying, output to the T end, be respectively above-mentioned two voltage comparators positive and anti-phase input are provided.
When sample rate current (IN point voltage) is timing (two switching tube Q1 and Q4 conducting), through oppositely amplifying, the T point voltage is for negative, it is the reverse voltage thresholding that amplifier U1B output makes the B point voltage, make diode D5 end, it is the forward voltage thresholding that amplifier U1C output simultaneously makes the C point voltage, makes diode D6 conducting, and OUT exports high level; As shown in Figure 3, t1 constantly, two switching tube Q1 and Q4 shutoff, freewheel current reduces, when freewheel current is reduced to when making T voltage less than R ' point voltage Ur ', diode D6 also ends, the OUT output low level; Detect the trailing edge signal of OUT this moment, corresponding to the t0 among Fig. 3 constantly, postpone a △ t then, during this period of time in, electric current is reduced to zero, and electric current is zero moment to be the t2 moment, and time-delay finishes, and arrives t3 ' constantly, two switching tube Q2 of another branch road of triggering and conducting, Q3, electric current begin reverse increase.
As sample rate current (IN point voltage) (two switching tube Q2 and Q3 conducting) when negative, through oppositely amplifying, the T point voltage is for just, it is the forward voltage thresholding that amplifier U1B output makes the B point voltage, make diode D5 conducting, it is the reverse voltage thresholding that amplifier U1C output simultaneously makes the C point voltage, makes diode D6 end, and OUT exports high level; As shown in Figure 3, t5 constantly, two switching tube Q2 and Q3 shutoff, freewheel current reduces, when freewheel current is reduced to when making T voltage less than R point voltage Ur, diode D5 also ends, the OUT output low level; Detect the trailing edge signal of OUT once more, then trigger and open switching tube Q1, Q4, corresponding to the t6 among Fig. 3 constantly, postpone a △ t then, during this period of time in, electric current is reduced to zero, electric current is zero moment to be the t7 moment, time-delay finishes, and arrives t8 constantly, two switching tube Q1 of another branch road of triggering and conducting, Q4, electric current begin reverse increase.So alternately, reduce duty ratio, be zero up to duty ratio at every turn, finishes demagnetization.Need to prove that △ t compares Td0 and Td ' is very little, the reference potential R point voltage of comparator is be provided with more little, just can make the precision of detection high more, and the OUT low level time is short more, and the △ t time-delay that provides also can be short more.
Fig. 5 is to prior art A, embodiment one B, the waveform of embodiment two C and their time of afterflow have carried out comparing intuitively, label etc. all with above-mentioned figure in identical, repeat no more.Therefrom as can be seen, the current waveform of embodiment one reaches seamless link, and the control time equals actual time of afterflow, and efficient is very high; Among the embodiment two, though the time-delay of a △ t is arranged, the ratio that △ t accounts in the time in The whole control is very little, can't influence the adaptivity and the high efficiency of control.
Claims (4)
1. the method for an inductive load commutation is characterized in that, this method comprises the steps:
Two reverse branch roads are set alternately powers to inductive load;
Load current is carried out real-time monitoring;
Whenever a route on-state transfers off-state to, the load afterflow, to be monitored be zero to freewheel current after, provide control command again, make another branch road transfer on-state to.
2. the method for inductive load commutation according to claim 1 is characterized in that, described control command is to monitor after electric current is zero, providing after time-delay 10～30ms.
3. the method for inductive load commutation according to claim 1 and 2 is characterized in that, the on-state of described branch road and off-state are to realize that its conducting and shutoff are subjected to the control of gate signal by the conducting of the controlled tr tube on the branch road with turn-offing.
4. the method for inductive load commutation according to claim 1 and 2 is characterized in that, controlled tr tube and fly-wheel diode reverse parallel connection.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010138622 CN101795087A (en) | 2010-04-02 | 2010-04-02 | Inductive load commutation method |
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| CN 201010138622 CN101795087A (en) | 2010-04-02 | 2010-04-02 | Inductive load commutation method |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106059359A (en) * | 2016-07-18 | 2016-10-26 | 杭州重芯力科技有限公司 | Bipolar power converter circuit and driving method |
| CN109192437A (en) * | 2018-09-27 | 2019-01-11 | 南京迪威尔高端制造股份有限公司 | A kind of three phase full wave rectification ultralow frequency demagnetizing method |
| CN109360708A (en) * | 2018-09-27 | 2019-02-19 | 南京迪威尔高端制造股份有限公司 | A kind of three phase full wave rectification ultralow frequency demagnetizer |
| CN112946351A (en) * | 2019-12-11 | 2021-06-11 | 圣邦微电子（北京）股份有限公司 | Negative follow current monitoring circuit |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0307057A1 (en) * | 1987-09-07 | 1989-03-15 | Alcatel Nederland B.V. | Energy convertor |
| CA2170317A1 (en) * | 1995-02-27 | 1996-08-28 | Juan Gonzalez | Control process for bidirectional current and inverter |
| JP3711334B2 (en) * | 2001-10-15 | 2005-11-02 | 三菱電機株式会社 | Switchgear |
| CN100420143C (en) * | 2005-04-13 | 2008-09-17 | 台达电子工业股份有限公司 | Control method and control circuit for brushless DC motor |
| CN100485831C (en) * | 2006-07-27 | 2009-05-06 | 西安鸣士机电开发有限公司 | Grinder chuck magnetizing and demagnetizing controller |
-
2010
- 2010-04-02 CN CN 201010138622 patent/CN101795087A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0307057A1 (en) * | 1987-09-07 | 1989-03-15 | Alcatel Nederland B.V. | Energy convertor |
| CA2170317A1 (en) * | 1995-02-27 | 1996-08-28 | Juan Gonzalez | Control process for bidirectional current and inverter |
| JP3711334B2 (en) * | 2001-10-15 | 2005-11-02 | 三菱電機株式会社 | Switchgear |
| CN100420143C (en) * | 2005-04-13 | 2008-09-17 | 台达电子工业股份有限公司 | Control method and control circuit for brushless DC motor |
| CN100485831C (en) * | 2006-07-27 | 2009-05-06 | 西安鸣士机电开发有限公司 | Grinder chuck magnetizing and demagnetizing controller |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106059359A (en) * | 2016-07-18 | 2016-10-26 | 杭州重芯力科技有限公司 | Bipolar power converter circuit and driving method |
| CN106059359B (en) * | 2016-07-18 | 2019-11-22 | 杭州重芯力科技有限公司 | Bipolar-type power converter circuit and driving method |
| CN109192437A (en) * | 2018-09-27 | 2019-01-11 | 南京迪威尔高端制造股份有限公司 | A kind of three phase full wave rectification ultralow frequency demagnetizing method |
| CN109360708A (en) * | 2018-09-27 | 2019-02-19 | 南京迪威尔高端制造股份有限公司 | A kind of three phase full wave rectification ultralow frequency demagnetizer |
| CN109360708B (en) * | 2018-09-27 | 2020-10-13 | 南京迪威尔高端制造股份有限公司 | Three-phase full-wave rectification ultralow frequency demagnetizer |
| CN112946351A (en) * | 2019-12-11 | 2021-06-11 | 圣邦微电子（北京）股份有限公司 | Negative follow current monitoring circuit |
| CN112946351B (en) * | 2019-12-11 | 2023-04-11 | 圣邦微电子（北京）股份有限公司 | Negative follow current monitoring circuit |
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Application publication date: 20100804 |