CN103546048B

CN103546048B - Current sample method

Info

Publication number: CN103546048B
Application number: CN201310528992.0A
Authority: CN
Inventors: 王志隆
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Digital Power Technologies Co Ltd
Priority date: 2013-10-30
Filing date: 2013-10-30
Publication date: 2018-03-06
Anticipated expiration: 2033-10-30
Also published as: CN103546048A

Abstract

The present invention relates to a current sampling method, which is applied to AC and DC power supply circuits. or, connect the current sampling circuit in series between the negative pole of the DC source in the AC and DC power supply circuits or between the AC source and the first end of the inductance; wherein, the current sampling circuit includes: A frequency AC transformer and a degaussing circuit, the power frequency AC transformer is used for sampling current, and the degaussing circuit is used for magnetically resetting the power frequency AC transformer; when the AC and DC power supply circuits are powered by a DC source , by controlling the first switch tube, the power frequency AC transformer is magnetically reset through the degaussing circuit.

Description

Current sample method

Technical field

The present invention relates to field of circuit technology, more particularly to a kind of current sample method.

Background technology

In AC and DC power supply circuit, exchange shares same AC and DC power supply circuit with direct current input, and AC and DC supplies Current sampling circuit plays very important effect in circuit, and the inductor current signal obtained by current sampling circuit will be straight The loop control for participating in AC and DC power supply circuit is connect, influences AC and DC power supply circuit work stable state and dynamic operational behaviour.Cause This, will ensure accuracy, the stability of current sampling circuit sampling as far as possible, while also to be avoided because current sample is to whole The negative effect that AC and DC power supply circuit is brought, and take into account cost.

Existing current sample method is typically to set to include high-frequency ac transformer in AC and DC power supply circuit （Current Transformer, CT）Current sampling circuit.As shown in figure 1, the current sampling circuit is gone here and there with switching tube Q3 Connection, is in series with diode D1, by sampling the electric current by switching tube Q3 and the electric current by diode D1（Or only sampling passes through Cross switching tube Q3 electric current）To reflect that actual inductive current participates in loop control and logical action.When input AC electric current （When i.e. by mains-supplied）, it is that no electric current realizes magnetic by inductance, high frequency CT by this period to have half of sinusoidal cycles Reset.And when input direct-current electric current（When being powered by DC source）, by taking CT1 as an example realized by the switching tube Q3 turn-off times CT magnetic resets.But A points voltage is clamped at+VO in switching tube Q3 shutdown moments, Fig. 1, now CT1 primary sides can produce one Individual induced electromotive force and A point voltages are added to switching tube Q3 drain electrodes and source electrode jointly, cause switching tube Q3 voltage stress to raise.

Therefore, existing current sample method can cause the voltage stress of switching tube in AC and DC power supply circuit to raise, from And the raising of switching speed is limited, increase the loss of switch tube.Although above mentioned problem can be by powering in AC and DC The current sampling circuit that being set in circuit includes hall device solves, but uses the circuit cost of hall device high, and needs Special current supply circuit is designed for hall device, adds the complexity of circuit, so as to reduce the reliability of circuit.

The content of the invention

In view of this, the invention provides a kind of current sample method, can be opened in reducing to AC and DC power supply circuit While closing the voltage stress of pipe, ensure the reliability of circuit.

In a first aspect, a kind of current sample method of offer of the embodiment of the present invention, applied to AC and DC power supply circuit, is somebody's turn to do Method includes：

Current sampling circuit is series to the positive pole or alternating current source and inductance of the DC source in the AC and DC power supply circuit First end between, the second end of the inductance is connected with the positive pole of first switch pipe；Or, current sampling circuit is series at institute Between negative pole or alternating current source and the first end of inductance of stating the dc source in AC and DC power supply circuit, the second of the inductance End is connected with the negative pole of first switch pipe；

Wherein, the current sampling circuit includes：Industrial frequency AC transformer and degaussing circuit, the industrial frequency AC transformer For sample rate current, the degaussing circuit is used to make the industrial frequency AC transformer carry out magnetic reset；

When the AC and DC power supply circuit is powered by DC source, by controlling the first switch pipe, so that described Industrial frequency AC transformer carries out magnetic reset by the degaussing circuit.

It is described when the AC and DC power supply circuit passes through direct current in the first mode in the cards of first aspect When source powers, by controlling the first switch pipe, so that the industrial frequency AC transformer carries out magnetic by the degaussing circuit Reset is specially：Opened by controlling the first switch pipe to be alternately in, off state, so that the industrial frequency AC transformer Carry out current sample；By controlling the first switch pipe to be continuously in off state, so that the industrial frequency AC transformer leads to Cross the degaussing circuit and carry out magnetic reset.

With reference to the first mode in the cards of first aspect, in second of mode in the cards, described in control First switch pipe alternately in open, the time of off state is more than and controls the first switch pipe to be continuously in off state Time.

Second with reference to the first of first aspect or first aspect mode in the cards or first aspect may be real Existing mode, in the third mode in the cards, first end and the DC source of the industrial frequency AC transformer primary side Negative or positive electrode or alternating current source be connected, the second end of the industrial frequency AC transformer primary side and the first end phase of the inductance Even；The secondary of the industrial frequency AC transformer is connected with the degaussing circuit.

Second with reference to the first of first aspect or first aspect mode in the cards or first aspect may be real Existing mode or the third mode in the cards of first aspect, in the 4th kind of mode in the cards, the demagnetization electricity Road includes：Resistance, blocking diode；The first end of the industrial frequency AC transformer secondary and the second end respectively with the resistance First end is connected with the second end, and the positive pole of the first end of the resistance also with the blocking diode is connected, and the of the resistance Two ends are grounded, and the negative pole of the blocking diode is sample rate current output end.

By such scheme, the current sampling circuit including industrial frequency AC transformer and degaussing circuit is series at cross, straight Between the positive pole or alternating current source and the first end of inductance that flow the DC source in power supply circuit, or, industrial frequency AC transformer will be included The negative pole or alternating current source and inductance of the DC source in AC and DC power supply circuit are series at the current sampling circuit of degaussing circuit Between first end, the reliable of circuit can be ensured while the voltage stress of switching tube in reducing to AC and DC power supply circuit Property.

Brief description of the drawings

Fig. 1 is the structural representation of the AC and DC power supply circuit with current sampling circuit in the prior art；

Fig. 2 is that a kind of structure of the AC and DC power supply circuit with current sampling circuit provided in an embodiment of the present invention is shown It is intended to；

Fig. 3 is the structural representation of current sampling circuit provided in an embodiment of the present invention.

Embodiment

In order that the object, technical solutions and advantages of the present invention are clearer, the present invention is made below in conjunction with accompanying drawing into One step it is described in detail, it is clear that the described embodiment only a part of embodiment of the present invention, rather than whole implementation Example.Based on the embodiment in the present invention, what those of ordinary skill in the art were obtained under the premise of creative work is not made All other embodiment, belongs to the scope of protection of the invention.

A kind of current sample method provided in an embodiment of the present invention is described in detail with reference to Fig. 2, and Fig. 2 is implemented for the present invention A kind of AC and DC power supply circuit including current sampling circuit that example provides.

As shown in Fig. 2 current sampling circuit 210 is series at DC source（Such as battery BAT）Positive pole and inductance L1 the Between one end.Specifically, current sampling circuit 210 passes through switching tube Q5 and DC source（Such as battery BAT）Positive pole is connected, switching tube Q5 positive pole is connected with the positive pole of DC source, and switching tube Q5 negative pole is connected with one end of current sampling circuit 210.Current sample One end that circuit 210 is not connected with inductance L1 is also connected with alternating current source.Specifically, current sampling circuit 210 not with inductance L1 phases One end even is connected by IGCT Q1 with the live wire of civil power.Inductance L1 the second end is connected with switching tube Q3 positive pole, switch Positive pole of the pipe Q3 positive pole also with sustained diode 1 is connected, and the negative pole of sustained diode 1 is connected with electric capacity C1 first end, Electric capacity C1 the second end is connected with switching tube Q3 negative pole；

Current sampling circuit 220 is series between the negative pole of DC source and inductance L2 first end.Specifically, electric current is adopted Sample circuit 220 is connected by switching tube Q6 with the negative pole of DC source, and switching tube Q6 negative pole is connected with the negative pole of DC source, switch Pipe Q6 positive pole is connected with one end of current sampling circuit 220.One end that current sampling circuit 220 is not connected with inductance L2 also with Alternating current source is connected.Specifically, current sampling circuit 220 does not pass through IGCT Q2 and the live wire of civil power with one end that inductance L2 is connected It is connected, inductance L2 the second end is connected with switching tube Q4 negative pole, the negative pole of switching tube Q4 negative pole also with sustained diode 2 It is connected, the positive pole of sustained diode 2 is connected with electric capacity C2 first end, electric capacity C2 the second end and switching tube Q4 positive pole phase Even；

The second of the positive pole and electric capacity C1 of switching tube Q3 negative pole and the tie point at electric capacity C1 the second end and switching tube Q4 The tie point at end is connected, and switching tube Q3 negative pole and the electric capacity C1 tie point at the second end are connected with the zero line of civil power.

It should be noted that switching tube Q3, switching tube Q4 can be insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT), or metal oxide layer-semiconductor-field-effect transistor（Metal-Oxide- Semiconductor Field-Effect Transistor,MOSFET）.As switching tube Q3, when switching tube Q4 is IGBT, open Close pipe Q3, switching tube Q4 just extremely colelctor electrode（C poles）, negative pole is emitter stage（E poles）.When switching tube Q3, switching tube Q4 are During MOSFET, switching tube Q3's, switching tube Q4 just extremely drains（D poles）, negative pole is source electrode（S poles）.Switching tube Q5 and switching tube Q6 is IGCT.

It is understood that the embodiment of the present invention only illustrates by taking the AC and DC power supply circuit described in Fig. 2 as an example, It can only include current sampling circuit 210 in AC and DC power supply circuit shown in Fig. 2 or only include current sampling circuit 220.And And current sampling circuit 210 in the present embodiment and current sampling circuit 220 can also be series at only alternating current source or only straight In the power supply circuit in stream source.

Wherein, current sampling circuit 210 is identical with the concrete structure of current sampling circuit 220, as shown in figure 3, current sample Circuit includes：Power frequency CT and degaussing circuit, degaussing circuit include resistance R1 and blocking diode D3.

Wherein, the first end of power frequency CT secondary and the second end are connected with resistance R1 first end and the second end respectively, resistance Positive pole of the R1 first end also with blocking diode D3 is connected, resistance R1 the second end ground connection, and blocking diode D3 negative pole is Sample rate current output end.

For current sampling circuit 210, the first end of power frequency CT primary sides is connected with switching tube Q5 negative pole, power frequency CT primary sides The second end be connected with inductance L1 first end.

For current sampling circuit 220, the first end of power frequency CT primary sides is connected with switching tube Q6 positive pole, power frequency CT primary sides The second end be connected with inductance L2 first end.

It is understood that degaussing circuit can also be realized otherwise, the present invention is not done to the structure of degaussing circuit Any restrictions.

When being powered by alternating current source, by taking current sampling circuit 210 as an example, because mains current is alternating current, During the positive half cycle of alternating current, power frequency CT1 carries out current sample, is exported by sample rate current output end.In the negative of alternating current During half cycle, power frequency CT1 is used without the time progress magnetic reset that electric current flows through, and avoids magnetic core saturation.

When being powered by DC source, by taking current sampling circuit 210 as an example, because direct current ource electric current is continuous direct current Stream, it is therefore desirable to demagnetization is carried out to power frequency CT1 using degaussing circuit by controlling switch pipe Q3, to avoid magnetic core saturation.

Specifically, by controlling switch pipe Q3 alternately in open, off state so that the cross, straight power supply circuit is realized Boost function, while power frequency CT1 carries out current sample, is exported by sample circuit output end.Continued by controlling switch pipe Q3 State is off, so that power frequency CT1 carries out magnetic reset by degaussing circuit.

Preferably, controlling switch pipe Q3 alternately in open, the time of off state is persistently located more than controlling switch pipe Q3 In the time of off state.

In a specific example, the current acquisition cycle is preset, within the time in each cycle 2/3, control is opened Close pipe Q3 alternately in open, off state inductive current IL directions as shown in Figure 3, power frequency CT1 sampling inductive currents pass through Blocking diode D3 exports current detection signal.

Within the time in each cycle 1/3, controlling switch pipe Q3 is continuously in off state.In this period, inductance electricity It is zero to flow IL.Power frequency CT1 secondary induces inverse electromotive force, and direction is that just 1. to put be negative for 2. point.Now due to ending two poles Pipe D3 presence, force the inverse electromotive force to be discharged by resistance R1, the energy accumulated during conducting is consumed, so that power frequency CT1 carries out magnetic reset.

When switching tube Q3 is turned off, A point voltages are clamped at+VO in Fig. 2, because power frequency CT1 does not go here and there with switching tube Q3 Connection, therefore will not additionally increase switching tube Q3 voltage stress.

It is understood that the current sample process of current sampling circuit 220 and the process to power frequency CT2 progress magnetic resets It is identical with current sampling circuit 210, it will not be repeated here.

By using current sample method provided in an embodiment of the present invention, industrial frequency AC transformer and degaussing circuit will be included Current sampling circuit be series at DC source in AC and DC power supply circuit positive pole or the first end of alternating current source and inductance it Between, or, the current sampling circuit including industrial frequency AC transformer and degaussing circuit is series at straight in AC and DC power supply circuit Between the negative pole or alternating current source in stream source and the first end of inductance, can reduce to AC and DC power supply circuit in switching tube voltage While stress, ensure the reliability of circuit.Due to using power frequency CT, therefore the cost of circuit there will not be and be increased.

Above-described embodiment, the purpose of the present invention, technical scheme and beneficial effect are carried out further Describe in detail, should be understood that the embodiment that the foregoing is only the present invention, be not intended to limit the present invention Protection domain, within the spirit and principles of the invention, any modification, equivalent substitution and improvements done etc., all should include Within protection scope of the present invention.

Claims

1. A current sampling method, applied to AC and DC power supply circuits, is characterized in that, the method comprises:

The current sampling circuit is connected in series between the positive pole of the DC source in the AC and DC power supply circuits or the live wire of the AC source and the first end of the inductance, and the second end of the inductance is connected to the positive pole of the first switch tube, so The negative pole of the first switching tube is connected to the negative pole of the DC source or the neutral line of the AC source; or, the current sampling circuit is connected in series with the negative pole of the DC power supply or the live wire of the AC source in the AC and DC power supply circuit Between the first end of the inductance, the second end of the inductance is connected to the negative pole of the first switch tube, and the positive pole of the first switch tube is connected to the positive pole of the DC source or the neutral line of the AC source;

Wherein, the current sampling circuit includes: a power frequency AC transformer and a degaussing circuit, the power frequency AC transformer is used for sampling current, and the degaussing circuit is used for magnetically resetting the power frequency AC transformer;

When the AC and DC power supply circuits are powered by a DC source, by controlling the first switch tube, the power frequency AC transformer is magnetically reset through the degaussing circuit.

2. The method according to claim 1, characterized in that, when the AC and DC power supply circuits are powered by a DC source, the power frequency AC transformer is passed through by controlling the first switching tube. The magnetic reset performed by the degaussing circuit is specifically:

By controlling the first switching tube to be alternately turned on and off, so that the power frequency AC transformer performs current sampling;

By controlling the first switching tube to be continuously in the off state, the power frequency AC transformer is magnetically reset through the degaussing circuit.

3 . The method according to claim 2 , wherein the time for controlling the first switch tube to be in the on-state and the off-state alternately is longer than the time for controlling the first switch tube to be in the off-state continuously. 4 .

4. The method according to any one of claims 1-3, wherein the first end of the primary side of the power frequency AC transformer is connected to the positive or negative pole of the DC source or the AC source, and the power frequency The second end of the primary side of the AC transformer is connected to the first end of the inductance;

The secondary side of the power frequency AC transformer is connected to the degaussing circuit.

5. The method according to any one of claims 1-3, wherein the degaussing circuit comprises: a resistor, a blocking diode;

The first end and the second end of the secondary side of the power frequency AC transformer are respectively connected to the first end and the second end of the resistor, and the first end of the resistor is also connected to the anode of the blocking diode, The second end of the resistor is grounded, and the cathode of the blocking diode is the sampling current output end.

6. The method according to claim 4, wherein the degaussing circuit comprises: a resistor, a blocking diode;