CN102901865A - Motor phase current detection circuit - Google Patents

Abstract

The invention discloses a motor phase current detection circuit, which comprises a switch module, a differential amplification module, an analog/digital conversion module and a control module, wherein a plurality of switch units are arranged in the switch module, and are connected in parallel; each switch unit comprises at least one switch and at least one resistor; the differential amplification module is connected with the switch module, and is used for performing differential amplification on voltage difference of two ends of the switch module to obtain a voltage signal subjected to differential amplification; the analog/digital conversion module is connected with the output end of the differential amplification module and is used for converting the voltage signal in an analog form into a voltage signal in a digital form; and the control module is connected with the output end of the analog/digital conversion module, and is used for controlling states of the switch units in the switch module according to the voltage signal to change the magnitude of a resistor between phase lines and improve the measurement accuracy.

Description

A kind of electric machine phase current testing circuit

Technical field

The present invention relates to the servocontrol field, relate in particular to a kind of electric machine phase current testing circuit.

Background technology

In the driver of motor, Current Control fast, accurately, can so that the motor operation more efficient with steadily.H bridge driving circuit is the core circuit unit in the motor driver, what flow through between the H bridge (the A end in the H bridge hold with B between) is the phase line current of motor, for motor phase line current is controlled, at first need the phase current of motor is measured, to obtain current current value.Prior art is to seal in the fixed-size resistance of resistance between phase line, such as the H bridge driving circuit of Fig. 1, by the voltage at measuring resistance R two ends, according to U=I*R(voltage=electric current * resistance), calculate the electric current in the phase line.

But motor is in motion process, and phase current is constantly to change in the motor, and when electric current is less, if the resistance that seals in is less, the voltage at resistance two ends is also less.Because voltage measuring apparatus is in the less measurement range of voltage, measuring accuracy is lower, therefore causes the current measurement precision to reduce.

Summary of the invention

In view of this, the invention provides a kind of electric machine phase current testing circuit, to overcome the low defective of current phasor measurement method precision in the prior art.

For achieving the above object, the existing scheme that proposes is as follows:

A kind of electric machine phase current testing circuit comprises:

Switch module, differential amplification module, mould/number conversion module and control module;

Have a plurality of switch elements in the described switch module, a plurality of described switch elements are parallel with one another;

Described differential amplification module links to each other with described switch module, is used for the voltage difference at described switch module two ends is carried out differential amplification, obtains the voltage signal behind the differential amplification;

Described mould/number conversion module links to each other with the output terminal of described differential amplification module, is used for the described voltage signal of analog form is converted to digital form;

Described control module links to each other with the output terminal of described mould/number conversion module, is used for according to described voltage signal, controls the state of each switch element in the described switch module;

Described switch element comprises at least one switch and at least one resistance; Described switch is connected with described resistance; The first end of described switch is connected with the output terminal of described control module, is used for receiving the control signal of described control module, and the second end links to each other with an end of described resistance, an end of the 3rd termination H bridge driving circuit; The other end of another termination H bridge driving circuit of described resistance.

Optionally, the resistance sum in each described switch element equates.

Optionally, resistance sum size in each described switch element is unequal, the switch element that has a resistance sum maximum, the resistance sum in the resistance sum in the switch element of described resistance sum maximum and other each described switch elements has proportionate relationship:

Wherein, R ₁Be the resistance sum in the switch element of described resistance sum maximum; R _nBe the resistance sum in n the switch element, n is positive integer.

Optionally, described switch module also comprises:

The basis sampling switching element, in parallel with described switch element, comprise at least one basic sampling resistor.

Optionally, the resistance sum in each described switch element equates, and the resistance sum equal and opposite in direction in described basic sampling resistor resistance sum and each the described switch element.

Optionally, basic sampling resistor resistance sum in the described basic sampling switching element is greater than the resistance sum in other each described switch element, and the resistance sum in the basic sampling resistor resistance sum in the described basic sampling switching element and other each the described switch element has proportionate relationship: $R_n=\frac{1}{n+1}R;$

Wherein, R is the basic sampling resistor resistance sum in the described basic sampling switching element; R _nBe the resistance sum in n the switch element, n is positive integer.

Optionally, described control module comprises:

Acquiring unit is used for obtaining the magnitude of voltage of mould/number conversion module output;

Computing unit is used for the resistance according to access channel in described magnitude of voltage and the switch module, calculates the current value between phase line;

Interval determining unit is used for determining that described current value is affiliated interval;

Control module is used for according to the corresponding relation of interval under the default described current value with access resistance, the state of each switch connection resistance in the gauge tap module.

Optionally, described basic sampling switching element also comprises at least one switch, and described switch is connected with described basic sampling resistor.

Can find out from above-mentioned technical scheme, technical solution of the present invention can dynamically be controlled the size of access resistance between phase line.According to interval corresponding relation with accessing resistance under the default current value, access meets the resistance of described corresponding relation, make and measure between phase line the voltage at resistance two ends in (H bridge driving circuit A end hold with B between) path more accurate, precision is higher, thereby according to U=I*R(voltage=electric current * resistance), calculate the electric current in the phase line, the precision of electric current also can improve greatly between the described phase line that calculates, avoid between phase line, accessing in the prior art fixed resistance and come measuring voltage, the low defective of precision that the method for calculating phase line current is brought.

Secondly, when electric current is larger, technical scheme of the present invention can be according to interval corresponding relation with accessing resistance under the default described current value, the resistance of the less resistance of access in the gauge tap module, avoided in the prior art, when the fixed resistance resistance was larger, the power consumption of generation was high, the defective that the resistance life-span is short.

In addition, control module is according to corresponding relation interval under the default current value and access resistance in the technical scheme of the present invention, fast gauge tap module basis sampling switching element or a switch element access channel, save the control step to switch element, improved work efficiency.

Can find out from above-mentioned technical scheme, in the electric machine phase current testing circuit disclosed by the invention, switch module between the access phase line is the resistor network of a parallel connection, by control module can the gauge tap module in the access state of resistance in the resistor network, thereby overcome the coarse defective of measurement that the available technology adopting fixed resistance brings, improved measuring accuracy.

Description of drawings

In order to be illustrated more clearly in the embodiment of the invention or technical scheme of the prior art, the below will do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art, apparently, accompanying drawing in the following describes only is some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain according to these accompanying drawings other accompanying drawing.

Fig. 1 is the circuit diagram of existing electric machine phase current testing circuit;

Fig. 2 is the circuit diagram of the embodiment of the invention one disclosed a kind of electric machine phase current testing circuit;

Fig. 3 is the circuit diagram of the embodiment of the invention one disclosed another electric machine phase current testing circuit;

Fig. 4 is the circuit diagram of the embodiment of the invention two disclosed a kind of electric machine phase current testing circuits;

Fig. 5 is the circuit diagram of the embodiment of the invention two disclosed another electric machine phase current testing circuit.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the invention, the technical scheme in the embodiment of the invention is clearly and completely described, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that obtains under the creative work prerequisite.

The embodiment of the invention discloses a kind of electric machine phase current testing circuit, to improve the precision that electric machine phase current is detected.

Embodiment one

Fig. 2 is the circuit diagram of the embodiment of the invention one disclosed a kind of electric machine phase current testing circuit, as shown in Figure 2, the disclosed electric machine phase current testing circuit of the present embodiment comprises: switch module 201, differential amplification module 202, mould/number conversion module 203 and control module 204;

Have a plurality of switch elements in the described switch module 201, a plurality of described switch elements are parallel with one another; Described switch element comprises at least one switch and at least one resistance, and described switch is connected with described resistance; The first end of described switch is connected with the output terminal of described control module, is used for receiving the control signal of described control module, and the second end links to each other with an end of described resistance, an end of the 3rd termination H bridge driving circuit; The other end of another termination H bridge driving circuit of described resistance;

For technical scheme disclosed by the invention is more clearly explained, one end of the H bridge driving circuit that is connected with the 3rd end of described switch, be designated as the A end of H bridge driving circuit, the other end of the H bridge driving circuit that is connected with the other end of described resistance, the B that is designated as H bridge driving circuit holds; Described resistance is the resistance that links to each other with switch in the switch element.Resistance is connected with resistance in the described switch element, the resistance sum equal and opposite in direction in the switch element of each relation in parallel, and in Fig. 2, R ₁=R ₂=R ₃=R _n

Wherein, R ₁Be the resistance sum in first switch element; R ₂Be second resistance sum in the switch element; R ₃Be the 3rd the resistance sum in the switch element; R _nBe the resistance sum in n the switch element, n is positive integer.

Fig. 3 is the circuit diagram of the embodiment of the invention one disclosed another electric machine phase current testing circuit.In Fig. 3, R ₁₁+ R ₁₂=R ₂₁+ R ₂₂==R ₃₁+ R ₃₂=R _N1+ R _N2

Wherein, R ₁₁+ R ₁₂Be the resistance sum in first switch element; R ₂₁+ R ₂₂Be second resistance sum in the switch element; R ₃₁+ R ₃₂Be the 3rd the resistance sum in the switch element; R _N1+ R _N2Be the resistance sum in n the switch element, n is positive integer.

Perhaps, resistance sum size in each described switch element is unequal, the switch element that has a resistance sum maximum, resistance sum in resistance sum in the switch element of described resistance sum maximum and other each described switch elements has proportionate relationship, in Fig. 2 ${\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HDA00002340702300031.png"\; state="\{\{state\}\}">R</figure-callout>}}_2=\frac{1}{2}{R}_1;$ $R_3=\frac{1}{3}{R}_1;$ $R_n=\frac{1}{n}{R}_1;$

Wherein, R ₁Be the resistance sum in first switch element; R ₂Be second resistance sum in the switch element; R ₃Be the 3rd the resistance sum in the switch element; R _nBe the resistance sum in n the switch element, n is positive integer.

In Fig. 3, $R_{21}+R_{22}=\frac{1}{3}(R_{11}+R_{12});$ $R_{31}+R_{32}==\frac{1}{3}(R_{11}+R_{12});$ $R_{n1}+R_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HDA00002340702300031.png"\; state="\{\{state\}\}">n</figure-callout>}2}=\frac{1}{n}(R_{11}+R_{12});$

Wherein, R ₁₁+ R ₁₂Be the resistance sum in first switch element; R ₂₁+ R ₂₂Be second resistance sum in the switch element; R ₃₁+ R ₃₂Be the 3rd the resistance sum in the switch element; R _N1+ R _N2Be the resistance sum in n the switch element, n is positive integer.

In Fig. 2, described differential amplification module 202 links to each other with described switch module 201, is used for the voltage difference at described switch module 201 two ends is carried out differential amplification, obtains the voltage signal behind the differential amplification;

Differential amplification module 202 comprises at least one differential amplifier circuit, and to the numerical range that mould/number conversion module 203 can gather, switch module 201 is placed between the H bridge driving circuit side a and b with the voltage difference differential amplification at described switch module 201 two ends.

Described mould/number conversion module 203 links to each other with the output terminal of described differential amplification module 202, is used for the described voltage signal of analog form is converted to digital form;

Mould/number conversion module 203 is sampled the voltage signal of analog form, keeps size constant and be converted to digital form.

Described control module 204 links to each other with the output terminal of described mould/number conversion module 203, is used for according to described voltage signal, controls the state of each switch element in the described switch module 201;

Control module 204, preferred, comprising:

Acquiring unit is used for obtaining the voltage signal of the digital form of mould/number conversion module 203 outputs:

Computing unit is used for the resistance according to access channel in described magnitude of voltage and the switch module, calculates the current value between phase line;

Interval determining unit is used for determining that described current value is affiliated interval;

Control module is used for according to the corresponding relation of interval under the default described current value with access resistance, the state of each switch connection resistance in the gauge tap module 201;

In Fig. 2, control module all switch closures at least one switch element in original state is gauge tap module 201.In the described switch module 201, during resistance sum equal and opposite in direction in the switch element of relation in parallel, i.e. R ₁=R ₂=R ₃=R _n

Wherein, R ₁Be the resistance sum in first switch element; R ₂Be second resistance sum in the switch element; R ₃Be the 3rd the resistance sum in the switch element; R _nBe the resistance sum in n the switch element, n is positive integer.

Optionally, control module is initially controlled all switch closures in any one switch element, supposes that control S1 is closed.

Resistance sum size in each described switch element is unequal, the switch element that has a resistance sum maximum, when the resistance sum in the resistance sum in the switch element of described resistance sum maximum and other each described switch elements has proportionate relationship, namely ${\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HDA00002340702300031.png"\; state="\{\{state\}\}">R</figure-callout>}}_2=\frac{1}{3}{R}_1;$ $R_3=\frac{1}{3}{R}_1;$ $R_n=\frac{1}{n}{R}_1;$

Wherein, R ₁Be the resistance sum in first switch element, be the resistance sum in the switch element of described resistance sum maximum; R ₂Be second resistance sum in the switch element; R ₃Be the 3rd the resistance sum in the switch element; R _nBe the resistance sum in n the switch element, n is positive integer.

Optionally, all switch closures in the switch element of the initial controlling resistance resistance of control module sum maximum are then controlled the S1 closure.

Measure under the original state voltage of (between phase line) between described switch module 201 two ends (H bridge driving circuit side a and b) with voltage table, voltage difference through 202 pairs of described switch modules of differential amplification module two ends is amplified, obtain the voltage signal behind the differential amplification, described voltage signal is through described mould/number conversion module 203, and the voltage signal of analog form becomes digital form.

Described control module 204 is used for according to described voltage signal, calculates the current value between phase line, determines that described current value is affiliated interval, according to the state of each switch in the interval corresponding relation gauge tap module 201 with accessing resistance under the default current value.In the described switch module 201, during resistance sum equal and opposite in direction in the switch element of relation in parallel, i.e. R ₁=R ₂=R ₃=R _n

Wherein, R ₁Be the resistance sum in first switch element; R ₂Be second resistance sum in the switch element; R ₃Be the 3rd the resistance sum in the switch element; R _nBe the resistance sum in n the switch element, n is positive integer.

Control module 204 is by all switch closures in the more switch elements of control, suppose all switch S 2 closures in second unit that opens the light of control, all switch S 3 of controlling in the 3rd switch element are also closed, form path in parallel, thereby the size of resistance in the gauge tap module 201 interior access channels, S2 and S3 be after the closure, the resistance in the switch module 201 interior access channels:

Wherein, R _tBe the equivalent resistance resistance in the described switch module 201 interior access channels; R ₁Be the resistance sum in first switch element.

In the described switch module 201, resistance sum size in each described switch element is unequal, the switch element that has a resistance sum maximum, when the resistance sum in the resistance sum in the switch element of described resistance sum maximum and other each described switch elements has proportionate relationship, control module 204 disconnects by switch in the switch element in the control path, supposes R ₁The place switch element is path, then controls S1 and disconnects, and according to interval corresponding relation with accessing resistance under the default current value, controls all switch closures in the switch element, supposes that control S3 is closed, then the resistance in the 201 interior access channels in the switch module:

Wherein, R _tBe the equivalent resistance resistance in the described switch module 201 interior access channels; R ₃Be the 3rd the resistance sum in the switch element; R ₁Be the resistance sum in first switch list.

In Fig. 3, control module all switch closures at least one switch element in original state is gauge tap module 301.In the described switch module 301, during resistance sum equal and opposite in direction in the switch element of relation in parallel, i.e. R ₁₁+ R ₁₂=R ₂₁+ R ₂₂==R ₃₁+ R ₃₂=R _N1+ R _N2

Wherein, R ₁₁+ R ₁₂Be the resistance sum in first switch element; R ₂₁+ R ₂₂Be second resistance sum in the switch element; R ₃₁+ R ₃₂Be the 3rd the resistance sum in the switch element; R _N1+ R _N2Be the resistance sum in n the switch element, n is positive integer.

Optionally, control module is initially controlled all switch closures in any one switch element, supposes that gauge tap S1 is closed.

Resistance sum size in each described switch element is unequal, the switch element that has a resistance sum maximum, when the resistance sum in the resistance sum in the switch element of described resistance sum maximum and other each described switch elements has proportionate relationship, namely $R_{21}+R_{22}=\frac{1}{3}(R_{11}+R_{12}),$ $R_{31}+R_{32}==\frac{1}{3}(R_{11}+R_{12}),$ $R_{n1}+{\mathrm{<figure-callout\; id="2"\; label="R\; n"\; filenames="HDA00002340702300031.png"\; state="\{\{state\}\}">R</figure-callout>}}_n=\frac{1}{n}(R_{11}+R_{12});$

Wherein, R ₁₁+ R ₁₂Be the resistance sum in first switch element; R ₂₁+ R ₂₂Be second resistance sum in the switch element; R ₃₁+ R ₃₂Be the 3rd the resistance sum in the switch element; R _N1+ R _N2Be the resistance sum in n the switch element, n is positive integer.

Optionally, all switch closures in the switch element of the initial controlling resistance resistance of control module sum maximum are then controlled the S1 closure.

Measure the voltage between described switch module 301 two ends (H bridge driving circuit side a and b) under the original state with voltage table, voltage difference through 302 pairs of described switch modules of differential amplification module two ends is amplified, obtain the voltage signal behind the differential amplification, described voltage signal is through described mould/number conversion module 303, and the voltage signal of analog form becomes digital form.

Described control module 304 is used for according to described voltage signal the state of each switch in the gauge tap module 301.In the described switch module 301, during resistance sum equal and opposite in direction in the switch element of relation in parallel, i.e. R ₁₁+ R ₁₂=R ₂₁+ R ₂₂==R ₃₁+ R ₃₂=R _N1+ R _N2

Wherein, R ₁₁+ R ₁₂Be the resistance sum in first switch element; R ₂₁+ R ₂₂Be second resistance sum in the switch element; R ₃₁+ R ₃₂Be the 3rd the resistance sum in the switch element; R _N1+ R _N2Be the resistance sum in n the switch element, n is positive integer.

Control module 304 is by all switch closures in the more switch elements of control, suppose all switch S 2 closures in second unit that opens the light of control, all switch S 3 of controlling in the 3rd switch element are also closed, form path in parallel, thereby the size of resistance in the gauge tap module 301 interior access channels, S2 and S3 be after the closure, the resistance in the switch module 301 interior access channels:

Wherein, R _tBe the equivalent resistance resistance in the described switch module 301 interior access channels; R ₁₁+ R ₁₂Be the resistance sum in first switch list.

In the described switch module 301, resistance sum size in each described switch element is unequal, the switch element that has a resistance sum maximum, when the resistance sum in the resistance sum in the switch element of described resistance sum maximum and other each described switch elements has proportionate relationship, control module 304 disconnects by switch in the switch element in the control path, supposes R ₁₁And R ₁₂The place switch element is path, then controls S1 and disconnects, according to interval corresponding relation with accessing resistance under the default current value, control all switch closures in the switch element, suppose that control S3 is closed, then the resistance in the 301 interior access channels in the switch module is assumed to be R _t, then $R_t=$ $R_{31}+R_{32}=\frac{1}{3}(R_{11}+R_{12});$

Wherein, R _tBe the equivalent resistance resistance in the described switch module 301 interior access channels; R ₁₁+ R ₁₂Be the resistance sum in first switch list, be the resistance sum in the switch element of described resistance sum maximum; R ₃₁+ R ₃₂Be the 3rd the resistance sum in the switch list.

As seen, technical solution of the present invention can dynamically be controlled the size of access resistance between phase line.According to interval corresponding relation with accessing resistance under the default current value, access meets the resistance of described corresponding relation, make and measure between phase line the voltage at resistance two ends in (H bridge driving circuit A end hold with B between) path more accurate, precision is higher, thereby according to U=I*R(voltage=electric current * resistance), calculate the electric current in the phase line, the precision of electric current also can improve greatly between the described phase line that calculates, avoid between phase line, accessing in the prior art fixed resistance and come measuring voltage, the low defective of precision that the method for calculating phase line current is brought.。

Secondly, when electric current is larger, technical scheme of the present invention can be according to interval corresponding relation with accessing resistance under the default described current value, the resistance of the less resistance of access in the gauge tap module, avoided in the prior art, when the fixed resistance resistance was larger, the power consumption of generation was high, the defective that the resistance life-span is short.

Embodiment two

Fig. 4 is the circuit diagram of the embodiment of the invention two disclosed a kind of electric machine phase current testing circuits, as shown in Figure 4, the disclosed electric machine phase current testing circuit of the present embodiment comprises: switch module 401, differential amplification module 402, mould/number conversion module 403 and control module 404;

Have a basic sampling switching element and a plurality of switch element in the described switch module 401, described basic sampling switching element and a plurality of described switch element are parallel with one another, one end of described basic sampling switching element one termination H bridge driving circuit, the other end of another termination H bridge driving circuit.Described switch element comprises at least one switch and at least one resistance, and described switch is connected with described resistance; The first end of described switch is connected with the output terminal of described control module 404, is used for receiving the control signal of described control module 404, and the second end links to each other with an end of described resistance, an end of the 3rd termination H bridge driving circuit; The other end of another termination H bridge driving circuit of described resistance;

For technical scheme disclosed by the invention is more clearly explained, one end of the H bridge driving circuit that is connected with the 3rd end of described switch, be designated as the A end of H bridge driving circuit, the other end of the H bridge driving circuit that is connected with the other end of described resistance, be designated as the B end of H bridge driving circuit, described resistance is the resistance that links to each other with switch in the switch element.In the described switch module 401, in described basic sampling switching element and the switch element, resistance is connected with resistance, the basis sampling switching element comprises at least one basic sampling resistor R, resistance sum equal and opposite in direction in the switch element of basis sampling resistor resistance sum and relation parallel with one another, in Fig. 4, R=R ₁=R ₂=R ₃=R _n

Wherein, R is the basic sampling resistor resistance sum in the described basic sampling switching element; R ₁Be the resistance sum in first switch element; R ₂Be second resistance sum in the switch element; R ₃Be the 3rd the resistance sum in the switch element; R _nBe the resistance sum in n the switch element, n is positive integer.

Perhaps, basic sampling resistor resistance sum in the described basic sampling switching element is greater than the resistance sum in other each described switch element, resistance sum in basic sampling resistor resistance sum in the described basic sampling switching element and other each the described switch element has proportionate relationship, and Fig. 5 is the circuit diagram of the embodiment of the invention two disclosed another electric machine phase current testing circuit.In Fig. 5, $R_1=\frac{1}{3}R;$ ${\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HDA00002340702300031.png"\; state="\{\{state\}\}">R</figure-callout>}}_2=\frac{1}{3}R;$ $R_n=\frac{1}{n+1}R;$

Wherein, R is the basic sampling resistor resistance sum in the described basic sampling switching element; R ₁Be the resistance sum in first switch element; R ₂Be second resistance sum in the switch element; R _nBe the resistance sum in n the switch element, n is positive integer.

Described differential amplification module 402 links to each other with described switch module 401, is used for the voltage difference at described switch module 401 two ends is carried out differential amplification, obtains the voltage signal behind the differential amplification;

Differential amplification module 402 comprises at least one differential amplifier circuit, and to the numerical range that mould/number conversion module 403 can gather, switch module 401 is placed between the H bridge driving circuit side a and b with the voltage difference differential amplification at described switch module 401 two ends.

Described mould/number conversion module 403 links to each other with the output terminal of described differential amplification module 402, is used for the described voltage signal of analog form is converted to digital form;

Mould/number conversion module 403 is sampled the voltage signal of analog form, keeps size constant and be converted to digital form.

Described control module 404 links to each other with the output terminal of described mould/number conversion module 403, is used for according to described voltage signal, controls the state of each switch element in the described switch module 401;

Control module 404, preferred, comprising:

Acquiring unit is used for obtaining the voltage signal of the digital form of mould/number conversion module 403 outputs:

Computing unit, be used for according to described magnitude of voltage with switch module in the resistance of access channel, calculate the current value between phase line;

Interval determining unit is used for determining that described current value is affiliated interval;

Control module is used for according to the corresponding relation of interval under the default described current value with access resistance, the state of each switch connection resistance in the gauge tap module 401;

That the switch in all switch elements disconnects in the gauge tap module 401 such as control module among Fig. 4 in original state, i.e. S1, S2, S3, Sn disconnects.In the described switch module 401, only having basic sampling switching element is path.Optionally, when the basic sampling switching element of relation parallel with one another and the resistance sum equal and opposite in direction in a plurality of switch element, i.e. R=R ₁=R ₂=R ₃=R _n

Wherein, R is the basic sampling resistor resistance sum in the described basic sampling switching element; R ₁Be the resistance sum in first switch element; R ₂Be second resistance sum in the switch element; R ₃Be the 3rd the resistance sum in the switch element; R _nBe the resistance sum in n the switch element, n is positive integer.

Under the control module original state, all switch S 1 in the gauge tap module 401, S2, S3, Sn disconnects.

Measure under the original state voltage of (between phase line) between described switch module 401 two ends (H bridge driving circuit side a and b) with voltage table, voltage difference through 402 pairs of described switch modules of differential amplification module, 401 two ends is amplified, obtain the voltage signal behind the differential amplification, described voltage signal is through described mould/number conversion module 403, and the voltage signal of analog form becomes digital form.

Described control module 404 is used for according to described voltage signal, calculates the current value between phase line, determines that described current value is affiliated interval, according to the state of each switch in the interval corresponding relation gauge tap module 401 with accessing resistance under the default current value.In the described switch module 401, when the basic sampling switching element of relation in parallel and the resistance sum equal and opposite in direction in the switch element, i.e. R=R ₁=R ₂=R ₃=R _n

Wherein, R is the basic sampling resistor resistance sum in the described basic sampling switching element; R ₁Be the resistance sum in first switch element; R ₂Be second resistance sum in the switch element; R ₃Be the 3rd the resistance sum in the switch element; R _nBe the resistance sum in n the switch element, n is positive integer.

Control module is by switch closure in the more switch elements of control, suppose all switch S 1 closures in unit that opens the light of control, all switch S 2 of controlling in another switch element are also closed, form path in parallel, thereby the size of resistance in the gauge tap module 401 interior access channels, S1 and S2 be after the closure, the resistance in the switch module 201 interior access channels:

Wherein, R _tBe the equivalent resistance resistance in the described switch module 401 interior access channels; R is the basic sampling resistor resistance sum in the described basic sampling switching element.

As seen, technical solution of the present invention can dynamically be controlled the size of access resistance between phase line.According to interval corresponding relation with accessing resistance under the default current value, access meets the resistance of described corresponding relation, make and measure between phase line the voltage at resistance two ends in (H bridge driving circuit A end hold with B between) path more accurate, precision is higher, thereby the precision that calculates the electric current in the phase line also can improve greatly.

Secondly, when electric current is larger, technical scheme of the present invention can be according to interval corresponding relation with accessing resistance under the default described current value, the resistance of the less resistance of access in the gauge tap module, avoided in the prior art, when the fixed resistance resistance was larger, the power consumption of generation was high, the defective that the resistance life-span is short.

In addition, the present embodiment accesses basic sampling switching element between phase line, so that under original state, needn't control again a path between whole switch closures formation phase lines in the switch element, just can carry out initial current detecting, save to a great extent operation, improve work efficiency.

In the technical scheme that Fig. 4 provides, by switch element being parallel to the size that changes resistance between phase line in the path, basic sampling resistor in the sampling switching element of basis is not directly received between phase line through switch, and basic sampling resistor resistance sum equals resistance sum in each switch element.Optionally, the resistance sum can not wait in basis sampling resistor resistance sum and each switch element, in Fig. 5, optionally, basic sampling resistor resistance sum in the described basic sampling switching element is greater than the resistance sum in other each described switch element, and the resistance sum in the basic sampling resistor resistance sum in the described basic sampling switching element and other each the described switch element has proportionate relationship: $R_1=\frac{1}{3}R;$ ${\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HDA00002340702300031.png"\; state="\{\{state\}\}">R</figure-callout>}}_2=\frac{1}{3}R;$ $R_n=\frac{1}{n+1}R;$

Wherein, R is the basic sampling resistor resistance sum in the described basic sampling switching element; R ₁Be the resistance sum in first switch element; R ₂Be second resistance sum in the switch element; R _nBe the resistance sum in n the switch element, n is positive integer.

When the basic sampling resistor resistance sum in the described basic sampling switching element greater than the resistance sum in other each described switch element, when the resistance sum in the basic sampling resistor resistance sum in the described basic sampling switching element and other each the described switch element has proportionate relationship, optionally, can comprise at least one switch in the basic sampling switching element.Control module original state be in the gauge tap module 504 in the basic sampling switching element all switch S closed, all switches disconnect in each switch element, namely control S1, S2, S3, Sn disconnects.Control module 504 disconnects by switch S in the basic sampling switching element in the control path, according to interval corresponding relation with accessing resistance under the default current value, control all switch closures in the switch element, suppose that control S2 is closed, then the resistance in the switch module 501 interior access channels:

Wherein, R _tBe the equivalent resistance resistance in the described switch module 501 interior access channels; R ₂Be the 2nd the resistance sum in the switch element; R is the basic sampling resistor resistance sum in the described basic sampling switching element.

As seen, technical solution of the present invention can dynamically be controlled the size of access resistance between phase line.According to interval corresponding relation with accessing resistance under the default current value, access meets the resistance of described corresponding relation, make and measure between phase line the voltage at resistance two ends in (H bridge driving circuit A end hold with B between) path more accurate, precision is higher, thereby the precision that calculates the electric current in the phase line also can improve greatly.

Secondly, when electric current is larger, technical scheme of the present invention can be according to interval corresponding relation with accessing resistance under the default described current value, the resistance of the less resistance of access in the gauge tap module, avoided in the prior art, when the fixed resistance resistance was larger, the power consumption of generation was high, the defective that the resistance life-span is short.

In addition, in the technical scheme that the present embodiment Fig. 5 provides, the basic sampling switching element of access between phase line, at least one switch of access in the sampling switching element of basis, basic sampling resistor resistance sum in the described basic sampling switching element is greater than the resistance sum in other each described switch element, resistance sum in basic sampling resistor resistance sum in the described basic sampling switching element and other each the described switch element has proportionate relationship, in testing process, original state is with all switch closures in the basic sampling switching element.Control module is according to corresponding relation interval under the default current value and access resistance, the switch of controlling in the basic sampling switching element disconnects, and control all switch closures in the selected switch element, perhaps, under the original state, the resistance in the switch module in the access channel meets the described interval of default current value and the corresponding relation that accesses resistance.In the technical scheme that illustration 5 provides, because the resistance in the switch module in the access channel all is in a switch element, the basic sampling switching element situation in parallel with at least one switch element that can occur in the technical scheme of having avoided Fig. 4 to provide, prolong the life-span of resistance, saved resource.

Secondly, control module 504 is according to corresponding relation interval under the default current value and access resistance, fast basic sampling switching element or a switch element access channel in the gauge tap module 501, can occur in the technical scheme of having avoided Fig. 4 to provide, control module 504 will be controlled the situation of a plurality of switch element access channels, save the control step to switch element, improved work efficiency.

Need to prove, in the embodiment of the invention, the number of switch element does not limit, and the number of resistance and switch does not limit in basic sampling switching element and the switch element.The size of each resistance does not limit in the switch element; only need resistance sum in the switch element of resistance sum maximum between phase line and the resistance sum in other each described switch elements to have proportionate relationship; the basis interior resistance sum of sampling switching element and each switch element equates or has a proportionate relationship; and; the proportionate relationship that the embodiment of the invention provides is a kind of optional reference case, and other proportionate relationships do not break away from protection scope of the present invention.

Each embodiment adopts the mode of going forward one by one to describe in this instructions, and what each embodiment stressed is and the difference of other embodiment that identical similar part is mutually referring to getting final product between each embodiment.

To the above-mentioned explanation of the disclosed embodiments, make this area professional and technical personnel can realize or use the present invention.Multiple modification to these embodiment will be apparent concerning those skilled in the art, and General Principle as defined herein can be in the situation that do not break away from the spirit or scope of the present invention, in other embodiments realization.Therefore, the present invention will can not be restricted to these embodiment shown in this article, but will meet the widest scope consistent with principle disclosed herein and features of novelty.

Claims (8)

1. an electric machine phase current testing circuit is characterized in that, comprising:

Switch module, differential amplification module, mould/number conversion module and control module;

Have a plurality of switch elements in the described switch module, a plurality of described switch elements are parallel with one another;

Described differential amplification module links to each other with described switch module, is used for the voltage difference at described switch module two ends is carried out differential amplification, obtains the voltage signal behind the differential amplification;

Described mould/number conversion module links to each other with the output terminal of described differential amplification module, is used for the described voltage signal of analog form is converted to digital form;

Described control module links to each other with the output terminal of described mould/number conversion module, is used for according to described voltage signal, controls the state of each switch element in the described switch module;

Described switch element comprises at least one switch and at least one resistance; Described switch is connected with described resistance; The first end of described switch is connected with the output terminal of described control module, is used for receiving the control signal of described control module, and the second end links to each other with an end of described resistance, an end of the 3rd termination H bridge driving circuit; The other end of another termination H bridge driving circuit of described resistance.

2. circuit according to claim 1 is characterized in that, the resistance sum in each described switch element equates.

3. circuit according to claim 1, it is characterized in that, resistance sum size in each described switch element is unequal, the switch element that has a resistance sum maximum, the resistance sum in the resistance sum in the switch element of described resistance sum maximum and other each described switch elements has proportionate relationship:

Wherein, R ₁Be the resistance sum in the switch element of described resistance sum maximum; R _nBe the resistance sum in n the switch element, n is positive integer.

4. circuit according to claim 1 is characterized in that, described switch module also comprises:

The basis sampling switching element, in parallel with described switch element, comprise at least one basic sampling resistor.

5. circuit according to claim 4 is characterized in that, the resistance sum in each described switch element equates, and the resistance sum equal and opposite in direction in described basic sampling resistor resistance sum and each the described switch element.

6. circuit according to claim 4, it is characterized in that, basic sampling resistor resistance sum in the described basic sampling switching element is greater than the resistance sum in other each described switch element, and the resistance sum in the basic sampling resistor resistance sum in the described basic sampling switching element and other each the described switch element has proportionate relationship:

Wherein, R is the basic sampling resistor resistance sum in the described basic sampling switching element; R _nBe the resistance sum in n the switch element, n is positive integer.

7. circuit according to claim 1 is characterized in that, described control module comprises:

Acquiring unit is used for obtaining the magnitude of voltage of mould/number conversion module output;

Computing unit is used for the resistance according to access channel in described magnitude of voltage and the switch module, calculates the current value between phase line;

Interval determining unit is used for determining that described current value is affiliated interval;

Control module is used for according to the corresponding relation of interval under the default described current value with access resistance, the state of each switch connection resistance in the gauge tap module.

8. the described circuit of any one is characterized in that according to claim 4-6, and described basic sampling switching element also comprises at least one switch, and described switch is connected with described basic sampling resistor.

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