CN202197244U - Motor position detection circuit adopting isolation type rotary transformer - Google Patents

Abstract

The utility model discloses a motor position detection circuit adopting an isolation type rotary transformer, consisting of a decoding chip, a Buffer circuit and a differential signal conditioning circuit, wherein an output end of the decoding chip is connected to an input end of the Buffer circuit, an output end of the Buffer circuit is connected to an input end of the rotary transformer, the rotary transformer outputs a sine-cosine differential signal to the differential signal conditioning circuit, the processed sine-cosine differential signal is input to the decoding chip; and the Buffer circuit comprises a front end filtering circuit, an operational amplifier control circuit, a push-pull circuit and a drive protection circuit. The motor position detection circuit of the utility model adopts the Buffer circuit with a power supply and a protection to realize power amplification of an excitation signal, thus the motor position detection circuit can be adapted to driving capabilities of different loads, and can realize the large-scale change of a peak-to-peak value of a differential voltage, thereby raising circuit stability, achieving a strong load adaptability, and achieving a good anti-interference capability; and the differential signal conditioning circuit with a direct current bias can realize level matching of the different rotary transformers and the decoding chip, thus the motor position detection circuit has the advantages of simple circuit structure, low cost and wide application scope.

Description

Adopt the motor position testing circuit of isolated resolver

Technical field

The utility model relates to the rotor position detection circuit of a kind of new-energy automobile with the high-power driving motor, relates in particular to a kind of motor position testing circuit that adopts isolated resolver.

Background technology

In the rotor position detection circuit of motor; At present commonly used have photoelectric encoder and a resolver; Wherein photoelectric encoder is a kind of transducer that the mechanical angle displacement on the output shaft is converted to pulse or digital quantity through opto-electronic conversion; And resolver is a kind of electromagnetic sensor, is used for measuring the rotating shaft angular travel and the angular speed of rotating object.Compare with photoelectric encoder, resolver has the reliability height, and stability is high; Cost is low; To insensitive advantages of environmental factor such as mechanical oscillation, temperature, humidity, in the motor position in new-energy automobile field detects, just progressively become a kind of transducer of main flow.

The rotating transformer structures of main flow is isolated at present; The transducer input need provide the pumping signal of certain power; Output two-way just, the cosine differential signal; Wherein pumping signal and just, cosine signal all is pure differential signal, therefore, the position detecting circuit of resolver mainly comprises pumping signal amplifying circuit and differential signal modulate circuit two large divisions.Wherein, the pumping signal amplifying circuit mainly contains the amplifier amplifying circuit, push-pull amplifier circuit, common Buffer amplifying circuit etc.; The differential signal modulate circuit mainly contains the amplifier modulate circuit, and resistance processing etc. are to satisfy the incoming level demand of decoding chip.

Adopt amplifier to amplify and have the limited shortcoming of amplifying power, directly adopt push-pull circuit or common Buffer circuit to amplify and then exist the stability of a system poor, shortcomings such as workload-adaptability difference.

The utility model content

The utility model technical problem to be solved provides a kind of motor position testing circuit that adopts isolated resolver, and its amplifying circuit stability improves, and workload-adaptability is strong, and antijamming capability is good, and the circuit of differential signal modulate circuit is simple, and cost is low.

For solving the problems of the technologies described above; The motor position testing circuit of the isolated resolver of employing that the utility model provides; Comprise decoding chip, Buffer circuit and differential signal modulate circuit; The output of said decoding chip is connected to the input of Buffer circuit; The output of Buffer circuit is connected to the input of resolver, and resolver output sine and cosine differential signal outputs signal to the input of decoding chip after the differential signal modulate circuit is handled to the differential signal modulate circuit.

Wherein, said Buffer circuit comprises front end filtering circuit, amplifier control circuit and modified model push-pull circuit.Said differential signal modulate circuit is a resistor network formula structure, the input that it is handled the sine and cosine differential signal of resolver output and exports decoding chip to.

Preferably; Said modified model push-pull circuit comprises push-pull circuit and a Drive Protecting Circuit; Said push-pull circuit comprises two continuous dissimilar triodes, No. two triodes, and said Drive Protecting Circuit is connected in parallel between the base stage of base stage and No. two triodes of a triode.

Further; Said Drive Protecting Circuit comprises No. three triodes, a diode, No. two diodes and No. four triodes of series connection successively, and wherein, the collector electrode of No. three triodes is connected to the base stage of a triode; Emitter links to each other with the positive pole of a diode; The negative pole of a diode links to each other with the positive pole of No. two diodes, and the negative pole of No. two diodes is connected to the emitter of No. four triodes, and the collector electrode of No. four triodes is connected to the base stage of No. two triodes; No. three triodes and a triode are the NPN type, and No. four triodes and No. two triodes are positive-negative-positive.

Preferably, said front end filtering circuit comprises an electric capacity, and said electric capacity links to each other with the output of decoding chip, and this electric capacity filters the DC component in the pumping signal of decoding chip output.

Preferably, said amplifier control circuit adopts the power supply of 30V power supply, comprises an operational amplifier and the feedback loop that links to each other with the operational amplifier negative terminal.

Further, the anode of said operational amplifier is input as reference voltage, and negative terminal is input as the pumping signal of filtering through the front end filtering circuit.Said feedback loop comprises first resistance, second resistance that is connected in parallel on the mutual series connection between Buffer circuit output end and the operational amplifier negative terminal, and an end ground connection, the feedback capacity of an end between first resistance and second resistance.

Further, also comprise filter circuit and protective circuit in the said differential signal modulate circuit.

The beneficial effect of the utility model is:

1, the input of resolver adopts the Buffer circuit of the band protection of power supply power supply to realize the power amplification of pumping signal; Compare with common Buffer circuit, increased Drive Protecting Circuit, can adapt to the unequally loaded driving force; The peak-to-peak value that can realize differential voltage through the parameter of regulating resistance and electric capacity changes about from 7.2V to 28V; Improved the stability of Buffer circuit, workload-adaptability is strong, and antijamming capability is good;

2, the differential signal modulate circuit of the output connecting band direct current biasing of resolver can be realized the level match of different rotary transformer and decoding chip through regulating the capacitance-resistance parameter, and its circuit structure is simple, and cost is low, and is applied widely.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is done further detailed explanation:

Fig. 1 is the system block diagram of the position detecting circuit of the utility model;

Fig. 2 is the circuit diagram of the Buffer amplifying circuit of the EXC pumping signal among the utility model embodiment;

Fig. 3 is the circuit diagram of the differential signal modulate circuit among the utility model embodiment.

Embodiment

The motor position testing circuit of the isolated resolver of employing of the utility model; As shown in Figure 1; Comprise decoding chip 1, Buffer circuit 2 and differential signal modulate circuit 4; The output of said decoding chip 1 is connected to the input of Buffer circuit 2; The output of Buffer circuit 2 is connected to the input of resolver 3, and resolver 3 output sine and cosine differential signals output signal to the input of decoding chip 1 after differential signal modulate circuit 4 is handled to differential signal modulate circuit 4.

In Fig. 1, the pumping signal single channel of decoding chip 1 can be used formula (1) expression to earth signal,

v _EXC＝v _offset+a·sin(wt) (1)

In the formula, a is the amplitude of the pumping signal EXC of decoding chip output, v _OffsetBe the DC component of EXC, asin (wt) is the alternating current component of EXC.

Will be behind the process Buffer circuit 2 with reference to direct current v _RefAmplify with the alternating current component of decoding chip 1 output, amplification coefficient is respectively k _DCAnd K _AC, and the excitation signals phase difference be 180 the degree, shown in following formula (2), (3),

The differential signal of excitation signals is suc as formula shown in (4)

The output signal of Buffer circuit 2 is exported two paths of differential signals behind resolver 3, be respectively Sin differential signal and Cos differential signal, shown in (5) and formula (6),

In the formula, COEFFICIENT K _RBe the no-load voltage ratio coefficient of resolver 3, θ is the electrical degree of resolver 3.

For the level requirement of matching and decoding chip 1, further carry out proportional zoom through the capacitance-resistance parameter of regulating differential signal modulate circuit 2.

In the present embodiment, said Buffer circuit 2 comprises front end filtering circuit, amplifier control circuit and modified model push-pull circuit.Said differential signal modulate circuit 4 is a resistor network formula structure, the input that it is handled the sine and cosine differential signal of resolver 3 outputs and exports decoding chip 1 to.As shown in Figure 2; Said front end filtering circuit comprises a capacitor C 11; Said capacitor C 11 links to each other with the output of decoding chip 1; DC component in the pumping signal of 11 pairs of decoding chips of this capacitor C, 1 output is filtered, and only keeps alternating current component, realizes the dc-isolation of front-end source circuit and rear end amplifying circuit.The modified model push-pull circuit comprises push-pull circuit and Drive Protecting Circuit of 30V power supply power supply; Said push-pull circuit comprises a triode Q1 of two continuous opposed polarities, No. two triode Q2, and said Drive Protecting Circuit is connected in parallel between the base stage of base stage and No. two triode Q2 of a triode Q1.

Fig. 2 is the Buffer amplifying circuit of EXC pumping signal, because/Buffer amplifying circuit and the EXC of EXC is just the same, phase phasic difference 180 degree of signal just, so only introduce the Buffer amplifying circuit of EXC here.Amplifier control circuit and push-pull circuit adopt the power supply of 30V power supply, and the amplifier control circuit comprises an operational amplifier U1 and the feedback loop that links to each other with operational amplifier U1 negative terminal.The anode of said operational amplifier U1 is input as DC reference voltage, and negative terminal is input as decoding chip 1 output and ac-excited signal that process capacitor C 11 is filtered.

Said feedback loop comprises first resistance R 36, second resistance R 48 of the mutual series connection that is connected in parallel between Buffer circuit output end and the operational amplifier negative terminal, and an end ground connection, the feedback capacity C13 of an end between first resistance R 36 and second resistance R 48.Carry out noise reduction through 12 pairs of ac-excited signals that filter through capacitor C 11 of capacitor C, operational amplifier output terminal is used to control the base potential of a triode Q1 and No. two triode Q2.First resistance R 36, second resistance R 48 through in the feedback loop can be amplified to DC reference voltage+15V about; Wherein DC reference voltage is suc as formula shown in (7); The direct current multiplication factor is suc as formula shown in (8), and the center voltage that is about to the Buffer circuit output signal is biased in+15V; First resistance R 36, second resistance R 48 and feedback capacity C13 through feedback loop exchanges amplification with the sinusoidal signal of decoding chip output simultaneously; Exchange multiplication factor suc as formula shown in (9), the amplitude multiplication factor is suc as formula shown in (10), and wherein the load characteristic of choosing by resolver of multiplication factor determines; And the pumping signal that is input to resolver 3 is pure differential signal; Shown in (4), strong thereby this circuit has been realized pumping signal to revolving change transducer adaptability, the performance that precision is high.

$V_{\mathrm{ref}}=\frac{R29}{R30+R29}*V_{30V}---\left(7\right)$

$K_{\mathrm{DC}}=\frac{R36+R48+R34}{R34}---\left(8\right)$

$K_{\mathrm{AC}}=\frac{R48//Z_{c13}+R36}{R31+Z_{c11}}---\left(9\right)$

$\left|K_{\mathrm{AC}}\right|=\frac{\sqrt{{(R_{36}\·R_{48})}^2+{[(R_{36}+R_{48})\·Z_{C13}]}^2}}{\sqrt{({R_{31}}^2+{Z_{C11}}^2)\·({R_{48}}^2+{Z_{C13}}^2)}}---\left(10\right)$

In Fig. 2, be parallel with a series connection circuit between the base stage of the base stage of a triode Q1 and No. two triode Q2, this series circuit is composed in series by No. three diode D7, first resistance R 23, second resistance R 21 and No. four diode D8.When static, to GND a quiescent current is arranged from+30V power supply, the voltage that between a triode Q1 and two base stages of No. two triode Q2, is produced does

U _B1B2＝U _D7+U _D8+U _R23+U _R21

R21 wherein, the R23 resistance is less, and R24 and R22 resistance are bigger, guarantee U _B1B2Be slightly larger than a triode Q1 and No. two triode Q2 emitter junction cut-in voltage sums; Thereby make two triode pipes all be in slightly conducting state; Regulate the resistance parameter of R36, R48 and R34 and can regulate the direct current multiplication factor, make the emitter current potential of a triode Q1 and No. two triode Q2 slightly equal 15V.When the output end voltage of amplifier changes by sinusoidal rule, because the dynamic electric resistor of No. three diode D7 and No. four diode D8 is very little, and R21, the resistance of R23 is less, can think that the base potential of a triode Q1 and No. two triode Q2 changes approximately equal.As sinusoidal excitation signal V _EXCWhen positive half cycle, u _B1E1Increase i _B1Increase emitter i _E1Also increase; Together should input signal u _iWhen negative half period, i _B2Increase emitter i _E2Also increase.

In order to improve the driving force of load; Between the base stage of a triode Q1 and No. two triode Q2, increased Drive Protecting Circuit; Comprise No. three triode Q3, a diode D5, No. two diode D6 and No. four triode Q4 of series connection successively, wherein, the collector electrode of No. three triode Q3 is connected to the base stage of a triode Q1; The emitter of No. three triode Q3 links to each other with the positive pole of a diode D5; The negative pole of a diode D5 links to each other with the positive pole of No. two diode D6, and the negative pole of No. two diode D6 is connected to the emitter of No. four triode Q4, and the collector electrode of No. four triode Q4 is connected to the base stage of No. two triode Q2; And the identical NPN type that is of the type of No. three triodes and a triode, the identical positive-negative-positive that is of type of No. four triodes and No. two triodes.In addition, as shown in Figure 2, resistance R 46 is the base resistance of No. three triode Q3, and resistance R 47 is the base resistance of No. four triode Q4, mainly plays metering function, and resistance R 27 and R28 then are used for controlling the emitter junction voltage of No. three triode Q3 and No. four triode Q4.When load is big, i _E1Increase, the voltage at resistance R 27 two ends increases, i.e. v _B3Increase u _B3E3Increase, thus No. three triode Q3 saturation conductions, thus u _B1E1Reduce i _B1Reduce i _E1Reduce; In like manner, when load hour, i _E1Reduce, the voltage at resistance R 27 two ends reduces, i.e. v _B3Reduce i _B3Reduce, thereby No. three triode Q3 get into linear zone, u _C3E3Increase, thus u _B1E1Increase i _B1Increase, thus i _E1Increase, therefore realized to adapt to load variations and self-regulating ability, also play a protective role simultaneously.

As shown in Figure 3, according to the requirement of no resolver 3 and 1 pair of level of decoding chip, just can satisfy the incoming signal level requirement of decoding chip 1 through the parameter of optimizing resistance R 8, R1, R3, R2, R9.In order to guarantee the biasing of single-ended common-mode signal,, guarantee that the minimum value of input signal is a positive voltage simultaneously, saved requirement simultaneously negative supply through resistance R 6, the last 2.5V power supply of moving to of R7.Also comprise filter circuit and protective circuit in the said differential signal modulate circuit 4.Protective circuit realizes through voltage-stabiliser tube W1, W2, prevent to burn out decoding chip 1 when peripheral signal is shorted to power supply, and filter circuit is realized through RC filtering, is respectively R4, C1 and R5, C2 among Fig. 3.

More than through specific embodiment the utility model has been carried out detailed explanation, this embodiment only is the preferred embodiment of the utility model, it is not that the utility model is limited.Under the situation that does not break away from the utility model principle, equivalent replacement and improvement that those skilled in the art makes circuit structure and electronic component etc. all should be regarded as in the technological category that the utility model is protected.

Claims (10)

1. motor position testing circuit that adopts isolated resolver; It is characterized in that; Comprise decoding chip, Buffer circuit and differential signal modulate circuit, the output of said decoding chip is connected to the input of Buffer circuit, and the output of Buffer circuit is connected to the input of resolver; Resolver output sine and cosine differential signal outputs signal to the input of decoding chip after the differential signal modulate circuit is handled to the differential signal modulate circuit.

2. the motor position testing circuit of the isolated resolver of employing according to claim 1 is characterized in that: said Buffer circuit comprises front end filtering circuit, amplifier control circuit and modified model push-pull circuit.

3. the motor position testing circuit of the isolated resolver of employing according to claim 2; It is characterized in that: said modified model push-pull circuit comprises push-pull circuit and a Drive Protecting Circuit; Said push-pull circuit comprises two continuous dissimilar triodes, No. two triodes, and said Drive Protecting Circuit is connected in parallel between the base stage of base stage and No. two triodes of a triode.

4. the motor position testing circuit of the isolated resolver of employing according to claim 3; It is characterized in that: said Drive Protecting Circuit comprises No. three triodes, a diode, No. two diodes and No. four triodes of series connection successively; Wherein, The collector electrode of No. three triodes is connected to the base stage of a triode, and emitter links to each other with the positive pole of a diode, and the negative pole of a diode links to each other with the positive pole of No. two diodes; The negative pole of No. two diodes is connected to the emitter of No. four triodes, and the collector electrode of No. four triodes is connected to the base stage of No. two triodes; No. three triodes and a triode are the NPN type, and No. four triodes and No. two triodes are positive-negative-positive.

5. the motor position testing circuit of the isolated resolver of employing according to claim 2; It is characterized in that: said front end filtering circuit comprises an electric capacity; Said electric capacity links to each other with the output of decoding chip, and this electric capacity filters the DC component in the pumping signal of decoding chip output.

6. the motor position testing circuit of the isolated resolver of employing according to claim 2 is characterized in that: said amplifier control circuit adopts the power supply of 30V power supply, comprises an operational amplifier and the feedback loop that links to each other with the operational amplifier negative terminal.

7. the motor position testing circuit of the isolated resolver of employing according to claim 6; It is characterized in that: the anode of said operational amplifier is input as DC reference voltage, and negative terminal is input as the pumping signal of the decoding chip output of filtering through the front end filtering circuit.

8. according to the motor position testing circuit of claim 6 or the isolated resolver of 3 described employings; It is characterized in that: said feedback loop comprises first resistance, second resistance that is connected in parallel on the mutual series connection between Buffer circuit output end and the operational amplifier negative terminal, and an end ground connection, the feedback capacity of an end between first resistance and second resistance.

9. the motor position testing circuit of the isolated resolver of employing according to claim 1; It is characterized in that: said differential signal modulate circuit is a resistor network formula structure, the input that it is handled the sine and cosine differential signal of resolver output and exports decoding chip to.

10. the motor position testing circuit of the isolated resolver of employing according to claim 9 is characterized in that: also comprise filter circuit and protective circuit in the said differential signal modulate circuit.

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