CN101672931A - Unipolar trapezoidal pulse current control method and device of inductive load - Google Patents

Abstract

The invention relates to a unipolar trapezoidal pulse current control method and a device of an inductive load, which are applicable to leading a sending machine with the transient electromagnetic method to generate pulse current in a sending coil and can be applied in the fields of geophysical prospecting and nondestructive detection. The method comprises the steps of setting the current amplitude of a constant current source and the current amplitude of a load, calculating a constant current inductor, setting the clamping voltage of an ascending edge and the clamping voltage of a descendingedge, changing the slopes of the ascending edge and the descending edge, leading a driving signal synthesis circuit to control the conduction and the disconnection of a switch tube and outputting theunipolar trapezoidal pulse current. The device comprises a direct current power supply, the constant current inductor, a control circuit of the constant current source, the inductive load, a constantvoltage clamping circuit of the ascending edge, the constant voltage clamping circuit of the descending edge, the current control circuit of the load, a time sequence control circuit, the driving signal synthesis circuit, a driving circuit and an electronic switch. The method and the device have the advantages that the method and the device realize the current linear ascending of the load, the front edge and the back edge are symmetric, the current amplitude of the load is constant, and the unipolar trapezoidal pulse current is generated.

Description

The Unipolar trapezoidal pulse current control method of inductive load and device

Technical field

The present invention relates to a kind of Unipolar trapezoidal pulse current control method and device of inductive load, be applicable to that the transmitter that transient electromagnetic method is surveyed produces pulse current in sending coil, be applied to geophysical survey, Non-Destructive Testing field.

Background technology

Transient electromagnetic method is one of important method of surveying information such as underground medium electrical parameter, has broad application prospects in ore prospecting, underground water detection, engineering monitoring and fields such as salting of soil investigation, Non-Destructive Testing.Transient electromagnetic method normally utilizes the pulse current of constant amplitude in the underground magnetic field of setting up one time, and pulse current periodically turn-offs, and detects the secondary magnetic field that geologic body produces, and by analyzing and handling the secondary field data, determines subsurface geologic structures.

At present, as excitation field source, prior art also mainly is the negative edge that utilizes square wave pulsed current to transient electromagnetic method with emission bipolar square wave pulse current.Adopt the reason of bipolar square wave pulse current to be, have no progeny, can produce opposite in sign, equal-sized induced voltage at inductive coil positive and negative closing to electric current, twice signal subtraction, but enhancing signal, and can eliminate system zero point.In fact, the rising edge of pulse current also is utilizable, if emission Unipolar trapezoidal pulse electric current, rising and falling edges can produce opposite in sign, equal-sized induced voltage at inductive coil equally.Adopt the bipolar square wave pulse current, its utilization ratio has reduced half, simultaneously, produces the bipolar square wave pulse current and need adopt full bridge structure, and power tube quantity is more, and power consumption is big, and control is complicated.If produce the Unipolar trapezoidal pulse electric current, main circuit will no longer need full bridge structure, and the quantity of power tube will reduce, and power consumption reduces greatly, and favourable reduction printer body is long-pending, makes system's lighting.

The main cause that rising edge is not utilized is: load is an inductive load, had a strong impact on the shape of transmitter current, pulse current is not desirable bipolar square wave, pulse current rising edge (forward position) is to rise by index or piecewise linearity, and the negative edge of pulse current (edge, back) is a ramp step wave shape, and before and after edge is asymmetric.As license number " linear adjustable control method and the device of current impulse negative edge ", can realize that the negative edge linearity is adjustable, but can not realize that the rising edge linearity is adjustable with rising edge load-carrying capacity for ZL200410081518.9.And for example license number is ZL200810069272.1 " the wide-frequency amplitude-constant AC square wave current control method and the device of inductive load ", can realize rising edge, negative edge linearity, but rising edge and negative edge are also asymmetric, and the electric current of generation is the bipolarity ac square wave.

Summary of the invention

The present invention is directed to above-mentioned deficiency, a kind of Unipolar trapezoidal pulse current control method and device of inductive load is provided, make the linear rising in transmitter current forward position, front and back, realized the Unipolar trapezoidal pulse electric current along symmetry.

In order to realize the foregoing invention purpose, technical scheme of the present invention is:

1. the Unipolar trapezoidal pulse current control method of an inductive load, this method step is in the following order carried out

(1). the S that closes a switch, by regulating sequential control 3, regulate output load current i _o(t) frequency, the cycle of load current must be greater than the opening of electronic switch, turn-off time sum;

(2). constant current source control circuit 6 and constant current inductance 2 constitute a constant current source, by regulating constant current source reference voltage circuit in the constant current source control circuit 6, set the constant current source current amplitude;

(3). load current reference voltage circuit in the regulating load current control circuit 1, set the load current amplitude;

(4). the output terminal of the output terminal of sequential control 3, constant current source control circuit 6 and the output terminal of load current control circuit 1, be connected respectively to the input end of drive signal combiner circuit 7, after drive signal combiner circuit 7 is pressed the computing of drive signal combiner circuit truth table 1-1 completion logic, difference output signal Y ₁, Y ₂To two input ends of driving circuit 8, two output terminals of driving circuit 8 are connected respectively to the first switching tube J ₁With second switch pipe J ₂Control end; Thereby the turn-on and turn-off of gauge tap pipe are pressed setpoint frequency output pulse current, and make the electric current and the load current of constant current source output all be stabilized in setting value;

Drive signal combiner circuit truth table 1-1

In the table:

1-represents high level; 0-represents low level;

K ₀-switch enable clock signal; K ₁-load current cycle signal;

K ₂-constant current source control circuit output signal; K ₃-load current control circuit output signal;

Y ₁-drive signal combiner circuit output end signal;

Y ₂Another output terminal output signal of-drive signal combiner circuit;

(5). set the constant voltage clamp voltage V of rising clamps 9 ₁Thereby, the slope of change transmitter current rising edge, V ₁Much larger than V _S, make the linear rising of rising edge, V ₁Must be less than the minimum rated insulation voltage of all switching tubes, all diodes;

(6). by formula 3. set the constant voltage clamp voltage V of decline clamps 10 ₂Thereby the slope of change transmitter current negative edge makes the linear decline of negative edge;

At t ₀Constantly: the electric current in the constant current inductance 2 reaches setting value;

At t ₀～t ₁During this time: the first switching tube J ₁Turn-off second switch pipe J ₂Conducting, constant current source and load inductance are connected, and load current begins to rise, and rising edge constant voltage clamping circuit 4 is started working, and provides rising edge constant voltage clamp voltage V to load ₁, V ₁Much larger than direct supply voltage V _S, load current rises to I by zero line;

At t ₂～t ₃During this time: switch enable clock signal K ₀Be high level 1, the first switching tube J ₁, second switch pipe J ₂Allow switch motion, the load current sample circuit conversion i in the load current control circuit 1 _o(t) be voltage signal, by with load current control circuit 1 in the load current reference voltage circuit make comparisons, make the first comparer A ₁Output a control signal to drive signal combiner circuit 7, after drive signal combiner circuit 7 is pressed the computing of drive signal combiner circuit truth table 1-1 completion logic, difference output signal Y ₁, Y ₂To two input ends of driving circuit 8, two output terminals of driving circuit 8 output a control signal to the first switching tube J respectively ₁With second switch pipe J ₂Control end, make the first switching tube J ₁, second switch pipe J ₂Turn-off or conducting the proof load current i _o(t) at setting value I;

At t ₃～t ₄During this time: the first switching tube J ₁Conducting, second switch pipe J ₂Turn-off, negative edge constant voltage clamping circuit 5 is started working, and provides negative edge constant voltage clamp voltage V to load ₂, make load current drop to zero by the I linearity;

At t ₀～t ₂During this time: switch enable clock signal K ₀Be low level 0, the first switching tube J ₁Keep off state, second switch pipe J ₂Keep conducting state, the first switching tube J ₁With second switch pipe J ₂The disable switch action guarantees that data acquisition is not subjected to the electronic switch noise;

At t ₃～t ₅During this time, switch enable clock signal K ₀Be low level 0, the first switching tube J ₁Keep conducting state, second switch pipe J ₂Keep off state, the first switching tube J ₁With second switch pipe J ₂The disable switch action guarantees that data acquisition is not subjected to the electronic switch noise;

Wherein:

Clamps is meant when it stands the high energy impact events of moment, can absorb instantaneous large-current, its both end voltage strangulation on a predetermined numerical value;

t ₀-load current begins to rise constantly; t ₁-load current rises to I constantly;

t ₂-switching tube enables constantly; t ₃-load current begins to descend constantly;

t ₄-load current drops to zero constantly; t ₅-switching tube enables constantly;

i _o(t)-load current; I-load current amplitude;

K ₀-switch enable clock signal;

Y ₁-drive signal combiner circuit output end signal;

Y ₂Another output terminal output signal of-drive signal combiner circuit;

V ₁-rising edge constant voltage clamp voltage; V ₂-negative edge constant voltage clamp voltage;

(7). computational load electric current negative edge slope absolute value P ₁, following " slope " all refers to the absolute value of slope:

i _o(t) drop to zero slope by I:

${\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="A2009101909450025H2.png,A2009101909450026H1.png"\; state="\{\{state\}\}">P</figure-callout>}}_1=\left|\frac{{\mathrm{di}}_0\left(t\right)}{\mathrm{dt}}\right|=\left|\frac{R_{L}I+V_2}{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="A2009101909450025H2.png,A2009101909450026H1.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}\right|$ ①

Wherein:

R _L-pull-up resistor; L ₁-load inductance amount;

I-load current amplitude; V ₂-negative edge constant voltage clamp voltage;

(8). computational load electric current rising edge slope P ₂

i _o(t) by the slope that is raised to I above freezing:

${\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="A2009101909450026H1.png"\; state="\{\{state\}\}">P</figure-callout>}}_2=\left|\frac{{\mathrm{di}}_0\left(t\right)}{\mathrm{dt}}\right|=\left|\frac{V_1}{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="A2009101909450025H2.png,A2009101909450026H1.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}\right|$ ②

Wherein:

L ₁-load inductance amount;

V ₁-rising edge constant voltage clamp voltage;

From 1., 2. two formulas change V as can be known ₁Or V ₂Value, make

V ₂＝V ₁-IR _L ③

Can realize that then load current rising and falling edges slope equates;

(9). the computational load electric current rises, fall time

Rise time of load current: ${\mathrm{<figure-callout\; id="1"\; label="t\; d"\; filenames="A2009101909450025H2.png,A2009101909450026H1.png"\; state="\{\{state\}\}">t</figure-callout>}}_d=-\frac{L_1}{R_L}\ln (1-\frac{{\mathrm{IR}}_L}{V_1})$ ④

Load current fall time: ${\mathrm{<figure-callout\; id="2"\; label="t\; d"\; filenames="A2009101909450026H1.png"\; state="\{\{state\}\}">t</figure-callout>}}_d=-\frac{L_1}{R_L}\ln \left(\frac{V_2}{{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="A2009101909450026H1.png"\; state="\{\{state\}\}">V</figure-callout>}}_2+{\mathrm{IR}}_L}\right)$ ⑤

Wherein:

t _D1-i _o(t) by the time that is raised to I above freezing; t _D2-i _o(t) drop to the zero time by I;

R _L-pull-up resistor; L ₁-load inductance amount;

V ₁-rising edge constant voltage clamp voltage; V ₂-negative edge constant voltage clamp voltage;

I-load current amplitude;

(10). the constant current inductance L ₂Determine

For realizing i _o(t) constant between period of output, i _L2(t) should therefore, can suppose i greater than I _L2(t) at load current i _o(t) rise to the I value and reach minimum value I constantly _L2mini _L2(t) maximal value rises to setting value I during load current is zero _L2maxAt load current between the rising stage, I _L2(t) electric current is pressed following formula decline

$i_{L2}\left(t\right)=I_{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A2009101909450026H1.png"\; state="\{\{state\}\}">L</figure-callout>}2\max }-\frac{V_1-V_S}{L_2}\mathrm{<figure-callout\; id="6"\; label="t"\; filenames="A2009101909450025H2.png,A2009101909450026H1.png"\; state="\{\{state\}\}">t</figure-callout>}$ ⑥

At t=t _D1Constantly, drop to minimum value,

$i_{L2}\left(t\right)=I_{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A2009101909450026H1.png"\; state="\{\{state\}\}">L</figure-callout>}2\max }-\frac{V_1-V_S}{L_2}{\mathrm{<figure-callout\; id="1"\; label="t\; d"\; filenames="A2009101909450025H2.png,A2009101909450026H1.png"\; state="\{\{state\}\}">t</figure-callout>}}_d=I_{L2\mathrm{<figure-callout\; id="7"\; label="min"\; filenames="A2009101909450025H2.png,A2009101909450026H1.png"\; state="\{\{state\}\}">min</figure-callout>}}$ ⑦

With 4. substitution following formula of formula:

${\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A2009101909450026H1.png"\; state="\{\{state\}\}">L</figure-callout>}}_2=\frac{L_1(V_1-V_S)\ln (1-\frac{{\mathrm{IR}}_L}{V_1})}{({\mathrm{<figure-callout\; id="2"\; label="I\; L"\; filenames="A2009101909450026H1.png"\; state="\{\{state\}\}">I</figure-callout>}}_L-{\mathrm{<figure-callout\; id="2"\; label="I\; L"\; filenames="A2009101909450026H1.png"\; state="\{\{state\}\}">I</figure-callout>}}_L){\mathrm{<figure-callout\; id="8"\; label="R\; L"\; filenames="A2009101909450025H2.png,A2009101909450026H1.png"\; state="\{\{state\}\}">R</figure-callout>}}_L}$ ⑧

Make load current constant, then must make: I _L2min＞I 9.

Wherein:

R _L-pull-up resistor; L ₁-load inductance amount;

V ₁-rising edge constant voltage clamp voltage; V _S-direct supply voltage;

i _L2(t)-the constant current source output current; I-load current amplitude;

I _L2minThe minimum current magnitude of-constant current source output;

I _L2maxThe maximum current amplitude of-constant current source output, the maximum current that can bear less than switching tube.

2. the Unipolar trapezoidal pulse current control device of an inductive load is characterized in that this device comprises direct supply V _S, constant current inductance 2, constant current source control circuit 6, sequential control 3, rising edge constant voltage clamping circuit 4, negative edge constant voltage clamping circuit 5, rising clamps 9, decline clamps 10, load current control circuit 1, drive signal combiner circuit 7, driving circuit 8, two all-controlling power electronics device first switching tube J ₁With second switch pipe J ₂, the first diode D ₁, second switch pipe D ₂, the 3rd diode D ₃With the 4th switching tube D ₄Direct supply V _SBe connected with switch S one end, the switch S other end is connected with constant current inductance 2 one ends, constant current inductance 2 other ends and the 5th diode D ₅Anodal connection, the 5th diode D ₅The A end of negative pole and inductive load 11 is connected the B end and the second switch pipe J of inductive load 11 ₂One end, the 4th diode D ₄Negative pole connect second switch pipe J ₂The other end and the 4th diode D ₄Positive pole, direct supply V _SNegative pole connects; The first switching tube J ₁One end and the 3rd diode D ₃Negative pole, the 5th diode D ₅Negative pole connect the first switching tube J ₁The other end and the 3rd diode D ₃Positive pole, direct supply V _SNegative pole is connected; The first diode D ₁The A end of positive pole and inductive load 11 be connected the first diode D ₁Negative pole connect an end of rising clamps 9, the other end of rising clamps 9 connects direct supply V _SNegative pole; The second diode D ₂The B end of positive pole and inductive load 11 be connected the second diode D ₂Negative pole be connected the other end of decline clamps 10 and direct supply V with an end of decline clamps 10 _SNegative pole connect.

3. the Unipolar trapezoidal pulse current device of inductive load according to claim 2 is characterized in that rising edge constant voltage clamping circuit 4 and negative edge constant voltage clamping circuit 5; The first diode D ₁Form rising edge constant voltage clamping circuit 4, the second diode D with rising clamps 9 ₂Form negative edge constant voltage clamping circuit 5 with decline clamps 10, rising edge constant voltage clamping circuit 4 and negative edge constant voltage clamping circuit 5 are connected respectively to A, the B two ends of inductive load 11, thereby provide rising edge constant voltage clamp voltage V to load ₁With negative edge constant voltage clamp voltage V ₂, make load current linearly rise and to descend.

4. the Unipolar trapezoidal pulse current device of inductive load according to claim 2 is characterized in that constant current source control circuit 6 and load current control circuit 1; Constant current source control circuit 6 comprises constant current source current sampling circuit, constant current source reference voltage circuit, by the second comparer A ₂And resistance R ₁, R ₂, R ₃The stagnant loop control circuit that constitutes, constant current source current sampling circuit conversion i _L2(t) be voltage signal, and and the constant current source reference voltage circuit compare, when its during less than the voltage of constant current source reference voltage circuit, constant current source control circuit 6 output signal K ₂Be high level 1, on the contrary K ₂Be low level 0; Load current control circuit 1 comprises load current sample circuit, load current reference voltage circuit and the first comparer A ₁, load current sample circuit conversion i _o(t) be voltage signal, and and the load current reference voltage circuit compare, when its during less than the voltage of load current reference voltage circuit, load current control circuit 1 output signal K ₃Be low level 0, on the contrary K ₃Be high level 1.

5. the Unipolar trapezoidal pulse current device of inductive load according to claim 2 is characterized in that drive signal combiner circuit 7; The input end of drive signal combiner circuit 7 is connected with the output terminal of constant current source control circuit 6, the output terminal of load current control circuit 1 and the output terminal of sequential control 3 respectively, two output terminals of drive signal combiner circuit 7 are connected respectively to two input ends of driving circuit 8, and two output terminals of driving circuit 8 are connected respectively to the first switching tube J ₁With second switch pipe J ₂Control end; The signal K of drive signal combiner circuit 7 by sequential control 3 is exported ₀And K ₁, constant current source control circuit 6 output signal K ₂Signal K with load current control circuit 1 output ₃By after the computing of drive signal combiner circuit truth table 1-1 completion logic, difference output signal Y ₁, Y ₂To two input ends of driving circuit 8, two output terminals of driving circuit 8 output a control signal to the first switching tube J respectively ₁, second switch pipe J ₂Control end, control the first switching tube J ₁, second switch pipe J ₂Conducting or shutoff, press setpoint frequency output pulse current, and make the electric current and the load current of constant current source output all be stabilized in setting value.

The present invention compared with prior art, its technique effect is:

Load current by zero to I and by I during the zero conversion, load voltage is distinguished clamper at rising edge constant voltage clamp voltage V ₁With negative edge constant voltage clamp voltage V ₂On, realized the linear rising of load current before and after edge, by formula 3. determine rising edge constant voltage clamp voltage V ₁With negative edge constant voltage clamp voltage V ₂Relation, can realize the before and after edge symmetry.

2. set the clamp voltage V of rising clamps 9 ₁Clamp voltage V with decline clamps 10 ₂Can realize respectively that current rise time and fall time are adjustable.

3. adopted constant current inductance 2 and load current control circuit 1, realized the constant of load current amplitude, the variation with supply voltage, frequency of operation, load does not change.

Description of drawings

Fig. 1 is the sequential chart of load current waveform figure of the present invention and timing control signal;

Fig. 2 is the composition frame chart of apparatus of the present invention;

Fig. 3 is the circuit topology of apparatus of the present invention composition frame chart;

Fig. 4 is actual measurement constant current source output current wave figure;

Fig. 5 is the Y of actual measurement drive signal combiner circuit output ₂Signal and load current waveform figure;

Fig. 6 is actual measurement load current rising edge waveform and clamp voltage oscillogram thereof;

Fig. 7 is actual measurement load current negative edge waveform and clamp voltage oscillogram thereof.

Last figure in Fig. 1 is load current waveform figure, and wherein the symbol implication is as follows:

t ₀-load current begins to rise constantly; t ₁-load current rises to I constantly;

t ₂-switching tube enables constantly; t ₃-load current begins to descend constantly;

t ₄-load current drops to zero constantly; t ₅-switching tube enables constantly;

t _D1-load current is by the zero time that begins to rise to I;

t _D2-load current begins to drop to zero time by I;

t _MdThe time of-switching tube hold mode;

i _o(t)-load current; I-load current amplitude.

Figure below among Fig. 1 is the sequential chart of timing control signal, and wherein the symbol implication is as follows:

The 1-high level; The 0-low level;

K ₀-switch enable clock signal; K ₁-load current cycle signal;

As switch enable clock signal K ₀Be low level 0, the first switching tube J ₁, second switch pipe J ₂Be in hold mode, the disable switch action guarantees that data acquisition is not subjected to the electronic switch noise; As switch enable clock signal K ₀Be high level 1, the first switching tube J ₁, second switch pipe J ₂Allow switch motion, make the electric current and the load current of constant current source output all be stabilized in setting value;

At t ₀Moment K ₁Be high level 1, second switch pipe J ₂Conducting, the first switching tube J ₁Turn-off K ₀Be low level 0, will keep the first switching tube J ₁, second switch pipe J ₂State this moment, the disable switch action; To t ₂Moment K ₀Be high level 1, allow the first switching tube J ₁, second switch pipe J ₂Switch motion is stablized the electric current of constant current source output and load current all in setting value; At t ₃Moment K ₁Be low level 0, second switch pipe J ₂Turn-off the first switching tube conducting J ₁, K ₀Be low level 0, will keep the first switching tube J ₁, second switch pipe J ₂State this moment, the disable switch action; To t ₅Moment K ₀Be high level 1, allow the first switching tube J ₁, second switch pipe J ₂Switch motion, the electric current of stablizing constant current source output is in setting value.

Among Fig. 2 to Fig. 3

The 1-load current control circuit; 2-constant current inductance;

The 3-sequential control; 4-rising edge constant voltage clamping circuit;

5-negative edge constant voltage clamping circuit; The 6-constant current source control circuit;

7-drive signal combiner circuit; The 8-driving circuit;

Among Fig. 3

9-rising clamps; 10-decline clamps;

The 11-inductive load;

K ₀-switch enable clock signal; K ₁-load current cycle signal;

K ₂-constant current source control circuit output signal; K ₃-load current control circuit output signal;

Y ₁-drive signal combiner circuit output end signal;

Y ₂Another output terminal output signal of-drive signal combiner circuit.

X represents horizontal ordinate among Fig. 4, and every lattice are 50 μ s; Y represents ordinate, and every lattice are 10A.

Last figure among Fig. 5 is the Y of actual measurement load current in the output of constant current drive signal synthesis circuit ₂Signal, X represents horizontal ordinate among the figure, and every lattice are 50 μ s, and Y represents ordinate, and every lattice are 5V; Figure below is the actual measurement load current waveform, and X represents horizontal ordinate among the figure, and every lattice are 50 μ s, and Y represents ordinate, and every lattice are 10A.

Last figure among Fig. 6 is an actual measurement load current rising edge waveform, and X represents horizontal ordinate among the figure, and every lattice are 50 μ s, and Y represents ordinate, and every lattice are 10A; Figure below is rising edge constant voltage clamp voltage V ₁Waveform, X represents horizontal ordinate among the figure, and every lattice are 50 μ s, and Y represents ordinate, and every lattice are 200V.

Last figure among Fig. 7 is an actual measurement load current negative edge waveform, and X represents horizontal ordinate among the figure, and every lattice are 50 μ s, and Y represents ordinate, and every lattice are 10A; Figure below is negative edge constant voltage clamp voltage V ₂Waveform, X represents horizontal ordinate among the figure, and every lattice are 50 μ s, and Y represents ordinate, and every lattice are 200V.

Embodiment

The present invention will be described in further details in conjunction with the accompanying drawings.

The concrete control method of this invention step is in the following order carried out:

1. the S that closes a switch by regulating sequential control 3, regulates output transmitter current i _o(t) frequency, the frequency that makes transmitter current is 32Hz;

2. regulate the constant current source reference voltage circuit in the constant current source control circuit 6, set the constant current source current amplitude, 7. calculate the constant current source electric current, make current amplitude reach setting value 28A by formula;

3. the load current reference voltage circuit in the regulating load current control circuit 1 is set the load current amplitude, makes current amplitude reach 20A;

4. adjust rising clamps 9, make rising edge constant voltage clamp voltage V ₁Reach 610V;

5. adjust decline clamps 10, make negative edge constant voltage clamp voltage V ₂Reach 600V;

6. switching tube adopts the IGBT module of 1200V, 100A;

7. the load current in the one-period:

At t ₀～t ₁During this time: the first switching tube J ₁Turn-off second switch pipe J ₂Conducting, the constant current inductance L ₂With load inductance L ₁Series connection, the first diode D ₁Conducting, with the load inductance voltage clamp at rising edge constant voltage clamp voltage V ₁On=the 610V, i _o(t) rise to I by zero line;

At t ₂～t ₃During this time: load current control circuit 1 outputs a control signal to drive signal combiner circuit 7, and drive signal combiner circuit 7 is by after the computing of drive signal combiner circuit truth table 1-1 completion logic, and output signal makes the first switching tube J to driving circuit 8 ₁, second switch pipe J ₂Turn-off or conducting the proof load current i _o(t) at setting value I;

At t ₃～t ₄During this time: the first switching tube J ₁Conducting, second switch pipe J ₂Turn-off the second diode D ₂Conducting, with the load inductance voltage clamp at negative edge constant voltage clamp voltage V ₂On=the 600V, i _o(t) drop to zero by the I linearity;

At t ₀～t ₂During this time: switch enable clock signal K ₀Be low level 0, the first switching tube J ₁Keep off state, second switch pipe J ₂Keep conducting state, the first switching tube J ₁With second switch pipe J ₂The disable switch action guarantees that data acquisition is not subjected to the electronic switch noise;

At t ₃～t ₅During this time, switch enable clock signal K ₀Be low level 0, the first switching tube J ₁Keep conducting state, second switch pipe J ₂Keep off state, the first switching tube J ₁With second switch pipe J ₂The disable switch action guarantees that data acquisition is not subjected to the electronic switch noise; Switch enable clock signal K ₀With load current cycle signal K ₁, constant current source control circuit output signal K ₂, load current control circuit output signal K ₃Logical relation see drive signal combiner circuit truth table 1-1;

Drive signal combiner circuit truth table 1-1

In the table:

1-represents high level; 0-represents low level;

K ₀-switch enable clock signal; K ₁-load current cycle signal;

K ₂-constant current source control circuit output signal; K ₃-load current control circuit output signal;

Y ₁-drive signal combiner circuit output end signal;

Y ₂Another output terminal output signal of-drive signal combiner circuit;

8. measured data: transmitter current 20A, direct supply voltage V _S=37.7V, the constant current inductance

L ₂=3.89mH, constant current source electric current 28A, inductive load internal resistance R _L=0.53 Ω, inductive load inductance value L ₁=1.51mH, rising edge constant voltage clamp voltage V ₁=610V, negative edge constant voltage clamp voltage V ₂=600V, electronic switch adopt the IGBT module of 1200V, 100A, current rise time t _D1=50 μ s; Downslope time t _D2=50 μ s;

9. computational load electric current negative edge slope P ₁, following " slope " all refers to the absolute value of slope:

i _o(t) drop to zero slope by I:

${\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="A2009101909450025H2.png,A2009101909450026H1.png"\; state="\{\{state\}\}">P</figure-callout>}}_1=\left|\frac{{\mathrm{di}}_0\left(t\right)}{\mathrm{dt}}\right|=\left|\frac{R_{L}I+V_2}{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="A2009101909450025H2.png,A2009101909450026H1.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}\right|=\left|\frac{0.53\&times;20+600}{1.51\&times;{10}^{-3}}\right|=404\&times;{10}^3$

Wherein: R _L=0.53 Ω, L ₁=1.51mH, I=20A, V ₂=600V;

10. computational load electric current rising edge slope P ₂

i _o(t) by the slope that is raised to I above freezing:

${\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="A2009101909450026H1.png"\; state="\{\{state\}\}">P</figure-callout>}}_2=\left|\frac{{\mathrm{di}}_0\left(t\right)}{\mathrm{dt}}\right|=\left|\frac{V_1}{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="A2009101909450025H2.png,A2009101909450026H1.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}\right|=\left|\frac{610}{1.51\&times;{10}^{-3}}\right|=404\&times;{10}^3$

Wherein: L ₁=1.51mH, V ₁=610V;

11. the computational load electric current rises, fall time

Rise time of load current: ${\mathrm{<figure-callout\; id="1"\; label="t\; d"\; filenames="A2009101909450025H2.png,A2009101909450026H1.png"\; state="\{\{state\}\}">t</figure-callout>}}_d=-\frac{L_1}{R_L}\ln (1-\frac{{\mathrm{IR}}_L}{V_1})$

Load current fall time: ${\mathrm{<figure-callout\; id="2"\; label="t\; d"\; filenames="A2009101909450026H1.png"\; state="\{\{state\}\}">t</figure-callout>}}_d=-\frac{L_1}{R_L}\ln \left(\frac{V_2}{{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="A2009101909450026H1.png"\; state="\{\{state\}\}">V</figure-callout>}}_2+{\mathrm{IR}}_L}\right)$

${\mathrm{<figure-callout\; id="1"\; label="t\; d"\; filenames="A2009101909450025H2.png,A2009101909450026H1.png"\; state="\{\{state\}\}">t</figure-callout>}}_d=-\frac{L_1}{R_L}\ln (1-\frac{{\mathrm{IR}}_L}{V_1})=-\frac{1.51\&times;{10}^{-3}}{0.53}\ln (1-\frac{20\&times;0.53}{610})=49.9\&times;{10}^{-6}s=49.9\mathrm{\&mu;s}$

${\mathrm{<figure-callout\; id="2"\; label="t\; d"\; filenames="A2009101909450026H1.png"\; state="\{\{state\}\}">t</figure-callout>}}_d=-\frac{L_1}{R_L}\ln \left(\frac{V_2}{{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="A2009101909450026H1.png"\; state="\{\{state\}\}">V</figure-callout>}}_2+{\mathrm{IR}}_L}\right)=-\frac{1.51\&times;{10}^{-3}}{0.53}\ln \left(\frac{600}{600+20\&times;0.53}\right)=49.8\&times;{10}^{-6}s=49.8\mathrm{\&mu;s}$

Wherein: L ₁=1.51mH, R _L=0.53 Ω, V ₁=610V, V ₂=600V, I=20A;

12. constant current inductance L ₂Determine

According to formula 8., 9. know

${\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A2009101909450026H1.png"\; state="\{\{state\}\}">L</figure-callout>}}_2=\frac{L_1(V_1-V_S)\ln (1-\frac{{\mathrm{IR}}_L}{V_1})}{({\mathrm{<figure-callout\; id="2"\; label="I\; L"\; filenames="A2009101909450026H1.png"\; state="\{\{state\}\}">I</figure-callout>}}_L-{\mathrm{<figure-callout\; id="2"\; label="I\; L"\; filenames="A2009101909450026H1.png"\; state="\{\{state\}\}">I</figure-callout>}}_L)R_L}=3.57\&times;{10}^{-3}H=3.57\mathrm{mH}$

Wherein: I _L2min=20A, I _L2max=28A, L ₁=1.51mH, R _L=0.53 Ω, V ₁=610V, V _S=37.7V.

As shown in Figure 2, the inventive system comprises direct supply V _S, constant current inductance 2, constant current source control circuit 6, sequential control 3, rising edge constant voltage clamping circuit 4, negative edge constant voltage clamping circuit 5, load current control circuit 1, drive signal combiner circuit 7, driving circuit 8, electronic switch.

As shown in Figure 3, direct supply V _SBe connected with switch S one end, the switch S other end is connected with constant current inductance 2 one ends, constant current inductance 2 other ends and the 5th diode D ₅Anodal connection, the 5th diode D ₅The A end of negative pole and inductive load 11 is connected the B end and the second switch pipe J of inductive load 11 ₂One end, the 4th diode D ₄Negative pole be connected second switch pipe J ₂The other end and the 4th diode D ₄Positive pole, direct supply V _SNegative pole is connected; The first switching tube J ₁One end and the 3rd diode D ₃Negative pole, the 5th diode D ₅Negative pole be connected the first switching tube J ₁The other end and the 3rd diode D ₃Positive pole, direct supply V _SNegative pole is connected; The first diode D ₁The A end of positive pole and inductive load 11 be connected the first diode D ₁Negative pole connect an end of rising clamps 9, the other end of rising clamps 9 connects direct supply V _SNegative pole; The second diode D ₂The B end of positive pole and inductive load 11 be connected the second diode D ₂Negative pole be connected the other end of decline clamps 10 and direct supply V with an end of decline clamps 10 _SNegative pole connect.

Constant current source control circuit 6 comprises constant current source current sampling circuit, constant current source reference voltage circuit, by the second comparer A ₂And resistance R ₁, R ₂, R ₃The stagnant loop control circuit that constitutes, constant current source current sampling circuit conversion i _L2(t) be voltage signal, and and the constant current source reference voltage circuit compare, when its during less than the voltage of constant current source reference voltage circuit, constant current source control circuit 6 output signal K ₂Be high level 1, on the contrary K ₂Be low level 0.

Load current control circuit 1 comprises load current sample circuit, load current reference voltage circuit and the first comparer A ₁, load current sample circuit conversion i _o(t) be voltage signal, and and the load current reference voltage circuit compare, when its during less than the voltage of load current reference voltage circuit, load current control circuit 1 output signal K ₃Be low level 0, on the contrary K ₃Be high level 1.

The input end of drive signal combiner circuit 7 is connected with the output terminal of constant current source control circuit 6, the output terminal of load current control circuit 1, the output terminal of sequential control 3 respectively, two output terminals of drive signal combiner circuit 7 are connected with two input ends of driving circuit 8 respectively, and two output terminals of driving circuit 8 are connected respectively to the first switching tube J ₁With second switch pipe J ₂Control end.

As load current i _oDuring (t) less than setting value I, load current sample circuit conversion i _o(t) be voltage signal, by with load current control circuit 1 in the load current reference voltage circuit make comparisons, make the first comparer A ₁Output control signal K ₃To drive signal combiner circuit 7, after drive signal combiner circuit 7 is pressed the computing of drive signal combiner circuit truth table 1-1 completion logic, output signal Y ₁To an input end of driving circuit 8, the output terminal of driving circuit 8 output high level 1 control signal is to the first switching tube J ₁Control end, make the first switching tube J ₁Turn-off, constant current source is given load inductance L ₁Makeup energy makes load current i _o(t) rise to I; In like manner, work as i _oDuring (t) greater than I, driving circuit 8 output terminal output low levels 0 control signal is to the first switching tube J ₁Control end, the first switching tube J ₁Conducting, load electricity L ₁Release energy, make load current i _o(t) drop to I, thereby keep load current at setting value I.

By the load current reference voltage circuit in the regulating load current control circuit 1, can realize that I's is adjustable.

By setting the clamp voltage V of rising clamps 9 ₁Clamp voltage V with decline clamps 10 ₂Can realize rising edge respectively, the negative edge slope is adjustable, thereby can realize rise time of load current and fall time is adjustable and rising edge and negative edge symmetry.

As shown in Figure 4: actual measurement constant current source electric current 28A, constant current inductance L ₂=3.89mH.

As Fig. 5, Fig. 6, shown in Figure 7: actual measurement transmitter current 20A, direct supply voltage V _S=37.7V, inductive load internal resistance R _L=0.53 Ω, inductive load inductance value L ₁=1.51mH, rising edge constant voltage clamp voltage V ₁=610V, negative edge constant voltage clamp voltage V ₂=600V, switching tube adopt the IGBT module of 1200V, 100A, current rise time t _D1=50 μ s; Downslope time t _D2=50 μ s.

The present invention realized that rising edge is linear and risen, and rising edge, negative edge slope can be in harmonious proportion rising edge, negative edge symmetry, make the load current constant amplitude, have produced the Unipolar trapezoidal pulse electric current.

Claims (5)

1, a kind of Unipolar trapezoidal pulse current control method of inductive load, it is characterized in that this method in the following order step carry out:

(1). the S that closes a switch, by regulating sequential control 3, regulate output load current i _o(t) frequency, the cycle of load current must be greater than the opening of electronic switch, turn-off time sum;

(2). constant current source control circuit 6 and constant current inductance 2 constitute a constant current source, by regulating constant current source reference voltage circuit in the constant current source control circuit 6, set the constant current source current amplitude;

(3). load current reference voltage circuit in the regulating load current control circuit 1, set the load current amplitude;

(4). the output terminal of the output terminal of sequential control 3, constant current source control circuit 6 and the output terminal of load current control circuit 1, be connected respectively to the input end of drive signal combiner circuit 7, after drive signal combiner circuit 7 is pressed the computing of drive signal combiner circuit truth table 1-1 completion logic, difference output signal Y ₁, Y ₂To two input ends of driving circuit 8, two output terminals of driving circuit 8 are connected respectively to the first switching tube J ₁With second switch pipe J ₂Control end; Thereby the turn-on and turn-off of gauge tap pipe are pressed setpoint frequency output pulse current, and make the electric current and the load current of constant current source output all be stabilized in setting value;

Drive signal combiner circuit truth table 1-1

In the table:

1-represents high level; 0-represents low level;

K ₀-switch enable clock signal; K ₁-load current cycle signal;

K ₂-constant current source control circuit output signal; K ₃-load current control circuit output signal;

Y ₁-drive signal combiner circuit output end signal;

Y ₂Another output terminal output signal of-drive signal combiner circuit;

(5). set the constant voltage clamp voltage V of rising clamps 9 ₁Thereby, the slope of change transmitter current rising edge, V ₁Much larger than V _S, make the linear rising of rising edge, V ₁Must be less than the minimum rated insulation voltage of all switching tubes, all diodes;

(6). by formula 3. set the constant voltage clamp voltage V of decline clamps 10 ₂Thereby the slope of change transmitter current negative edge makes the linear decline of negative edge;

At t ₀Constantly: the electric current in the constant current inductance 2 reaches setting value;

At t ₀～t ₁During this time: the first switching tube J ₁Turn-off second switch pipe J ₂Conducting, constant current source and load inductance are connected, and load current begins to rise, and rising edge constant voltage clamping circuit 4 is started working, and provides rising edge constant voltage clamp voltage V to load ₁, V ₁Much larger than direct supply voltage V _S, load current rises to I by zero line;

At t ₂～t ₃During this time: switch enable clock signal K ₀Be high level 1, the first switching tube J ₁, second switch pipe J ₂Allow switch motion, the load current sample circuit conversion i in the load current control circuit 1 _o(t) be voltage signal, by with load current control circuit 1 in the load current reference voltage circuit make comparisons, make the first comparer A ₁Output a control signal to drive signal combiner circuit 7, after drive signal combiner circuit 7 is pressed the computing of drive signal combiner circuit truth table 1-1 completion logic, difference output signal Y ₁, Y ₂To two input ends of driving circuit 8, two output terminals of driving circuit 8 output a control signal to the first switching tube J respectively ₁With second switch pipe J ₂Control end, make the first switching tube J ₁, second switch pipe J ₂Turn-off or conducting the proof load current i _o(t) at setting value I;

At t ₃～t ₄During this time: the first switching tube J ₁Conducting, second switch pipe J ₂Turn-off, negative edge constant voltage clamping circuit 5 is started working, and provides negative edge constant voltage clamp voltage V to load ₂, make load current drop to zero by the I linearity;

At t ₀～t ₂During this time: switch enable clock signal K ₀Be low level 0, the first switching tube J ₁Keep off state, second switch pipe J ₂Keep conducting state, the first switching tube J ₁With second switch pipe J ₂The disable switch action guarantees that data acquisition is not subjected to the electronic switch noise;

At t ₃～t ₅During this time, switch enable clock signal K ₀Be low level 0, the first switching tube J ₁Keep conducting state, second switch pipe J ₂Keep off state, the first switching tube J ₁With second switch pipe J ₂The disable switch action guarantees that data acquisition is not subjected to the electronic switch noise;

Wherein:

Clamps is meant when it stands the high energy impact events of moment, can absorb instantaneous large-current, its both end voltage strangulation on a predetermined numerical value;

t ₀-load current begins to rise constantly; t ₁-load current rises to I constantly;

t ₂-switching tube enables constantly; t ₃-load current begins to descend constantly;

t ₄-load current drops to zero constantly; t ₅-switching tube enables constantly;

i _o(t)-load current; I-load current amplitude;

K ₀-switch enable clock signal;

Y ₁-drive signal combiner circuit output end signal;

Y ₂Another output terminal output signal of-drive signal combiner circuit;

V ₁-rising edge constant voltage clamp voltage; V ₂-negative edge constant voltage clamp voltage;

(7). computational load electric current negative edge slope absolute value P ₁, following " slope " all refers to the absolute value of slope:

i _o(t) drop to zero slope by I:

$P_1=\left|\frac{{\mathrm{di}}_0\left(t\right)}{\mathrm{dt}}\right|=\left|\frac{R_{L}I+V_2}{L_1}\right|$ ①

Wherein:

R _L-pull-up resistor; L ₁-load inductance amount;

I-load current amplitude; V ₂-negative edge constant voltage clamp voltage;

(8). computational load electric current rising edge slope P ₂

i _o(t) by the slope that is raised to I above freezing:

$P_2=\left|\frac{{\mathrm{di}}_0\left(t\right)}{\mathrm{dt}}\right|=\left|\frac{V_1}{L_1}\right|$ ②

Wherein:

L ₁-load inductance amount;

V ₁-rising edge constant voltage clamp voltage;

From 1., 2. two formulas change V as can be known ₁Or V ₂Value, make

V ₂＝V ₁-IR _L ③

Can realize that then load current rising and falling edges slope equates;

(9). the computational load electric current rises, fall time

Rise time of load current: $t_{d1}=-\frac{L_1}{R_L}\ln (1-\frac{{\mathrm{IR}}_L}{V_1})$ ④

Load current fall time: $t_{d2}=-\frac{L_1}{R_L}\ln \left(\frac{V_2}{V_2+{\mathrm{IR}}_L}\right)$ ⑤

Wherein:

t _D1-i _o(t) by the time that is raised to I above freezing; t _D2-i _o(t) drop to the zero time by I;

R _L-pull-up resistor; L ₁-load inductance amount;

V ₁-rising edge constant voltage clamp voltage; V ₂-negative edge constant voltage clamp voltage;

I-load current amplitude;

(10). the constant current inductance L ₂Determine

For realizing i _o(t) constant between period of output, i _L2(t) should therefore, can suppose i greater than I _L2(t) at load current i _o(t) rise to the I value and reach minimum value I constantly _L2mini _L2(t) maximal value rises to setting value I during load current is zero _L2maxAt load current between the rising stage, i _L2(t) electric current is pressed following formula decline

$i_{L2}\left(t\right)=I_{L2\max }-\frac{V_1-V_S}{L_2}t$ ⑥

At t=t _D1Constantly, drop to minimum value,

$i_{L2}\left(t\right)=I_{L2\max }-\frac{V_1-V_S}{L_2}{t}_{d1}=I_{L2\min }$ ⑦

With 4. substitution following formula of formula:

$L_2=\frac{L_1(V_1-V_S)\ln (1-\frac{{\mathrm{IR}}_L}{V_1})}{(I_{L2\min }-I_{L2\max })R_L}$ ⑧

Make load current constant, then must make: I _L2min＞I 9.

Wherein:

R _L-pull-up resistor; L ₁-load inductance amount;

V ₁-rising edge constant voltage clamp voltage; V _S-direct supply voltage;

i _L2(t)-the constant current source output current; I-load current amplitude;

I _L2minThe minimum current magnitude of-constant current source output;

I _L2maxThe maximum current amplitude of-constant current source output, the maximum current that can bear less than switching tube.

2. the Unipolar trapezoidal pulse current control device of an inductive load is characterized in that this device comprises direct supply V _S, constant current inductance 2, constant current source control circuit 6, sequential control 3, rising edge constant voltage clamping circuit 4, negative edge constant voltage clamping circuit 5, rising clamps 9, decline clamps 10, load current control circuit 1, drive signal combiner circuit 7, driving circuit 8, two all-controlling power electronics device first switching tube J ₁With second switch pipe J ₂, the first diode D ₁, second switch pipe D ₂, the 3rd diode D ₃With the 4th switching tube D ₄Direct supply V _SBe connected with switch S one end, the switch S other end is connected with constant current inductance 2 one ends, constant current inductance 2 other ends and the 5th diode D ₅Anodal connection, the 5th diode D ₅The A end of negative pole and inductive load 11 is connected the B end and the second switch pipe J of inductive load 11 ₂One end, the 4th diode D ₄Negative pole connect second switch pipe J ₂The other end and the 4th diode D ₄Positive pole, direct supply V _SNegative pole connects; The first switching tube J ₁One end and the 3rd diode D ₃Negative pole, the 5th diode D ₅Negative pole connect the first switching tube J ₁The other end and the 3rd diode D ₃Positive pole, direct supply V _SNegative pole is connected; The first diode D ₁The A end of positive pole and inductive load 11 be connected the first diode D ₁Negative pole connect an end of rising clamps 9, the other end of rising clamps 9 connects direct supply V _SNegative pole; The second diode D ₂The B end of positive pole and inductive load 11 be connected the second diode D ₂Negative pole be connected the other end of decline clamps 10 and direct supply V with an end of decline clamps 10 _SNegative pole connect.

3. the Unipolar trapezoidal pulse current device of inductive load according to claim 2 is characterized in that rising edge constant voltage clamping circuit 4 and negative edge constant voltage clamping circuit 5; The first diode D ₁Form rising edge constant voltage clamping circuit 4, the second diode D with rising clamps 9 ₂Form negative edge constant voltage clamping circuit 5 with decline clamps 10, rising edge constant voltage clamping circuit 4 and negative edge constant voltage clamping circuit 5 are connected respectively to A, the B two ends of inductive load 11, thereby provide rising edge constant voltage clamp voltage V to load ₁With negative edge constant voltage clamp voltage V ₂, make load current linearly rise and to descend.

4. the Unipolar trapezoidal pulse current device of inductive load according to claim 2 is characterized in that constant current source control circuit 6 and load current control circuit 1; Constant current source control circuit 6 comprises constant current source current sampling circuit, constant current source reference voltage circuit, by the second comparer A ₂And resistance R ₁, R ₂, R ₃The stagnant loop control circuit that constitutes, constant current source current sampling circuit conversion i _L2(t) be voltage signal, and and the constant current source reference voltage circuit compare, when its during less than the voltage of constant current source reference voltage circuit, constant current source control circuit 6 output signal K ₂Be high level 1, on the contrary K ₂Be low level 0; Load current control circuit 1 comprises load current sample circuit, load current reference voltage circuit and the first comparer A ₁, load current sample circuit conversion i _o(t) be voltage signal, and and the load current reference voltage circuit compare, when its during less than the voltage of load current reference voltage circuit, load current control circuit 1 output signal K ₃Be low level 0, on the contrary K ₃Be high level 1.

5. the Unipolar trapezoidal pulse current device of inductive load according to claim 2 is characterized in that drive signal combiner circuit 7; The input end of drive signal combiner circuit 7 is connected with the output terminal of constant current source control circuit 6, the output terminal of load current control circuit 1 and the output terminal of sequential control 3 respectively, two output terminals of drive signal combiner circuit 7 are connected respectively to two input ends of driving circuit 8, and two output terminals of driving circuit 8 are connected respectively to the first switching tube J ₁With second switch pipe J ₂Control end; The signal K of drive signal combiner circuit 7 by sequential control 3 is exported ₀And K ₁, constant current source control circuit 6 output signal K ₂Signal K with load current control circuit 1 output ₃By after the computing of drive signal combiner circuit truth table 1-1 completion logic, difference output signal Y ₁, Y ₂To two input ends of driving circuit 8, two output terminals of driving circuit 8 output a control signal to the first switching tube J respectively ₁, second switch pipe J ₂Control end, control the first switching tube J ₁, second switch pipe J ₂Conducting or shutoff, press setpoint frequency output pulse current, and make the electric current and the load current of constant current source output all be stabilized in setting value.

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