CN103078571A - Rotary transformer system and control method thereof - Google Patents

Abstract

The invention discloses a rotary transformer system and a control method thereof. A digital signal control chip modulates and outputs a sinusoidal excitation signal with preset frequency, the sinusoidal excitation signal is used as rated voltage of a rotary transformer after being conditioned; a zero passage moment of the sinusoidal excitation signal is used as an interrupt signal of the digital signal control chip; a timer of the digital signal control chip starts to count by taking the zero passage moment as a time reference, the digital signal control chip collects an AD sample of a sine and cosine signal of the rotary transformer after 1/4 period is delayed; the rotary transformer outputs two sine and cosine modulation and simulation signals; a signal conditioning circuit is used for conditioning the two sine and cosine modulation and simulation signals to obtain the conditioned simulation signals to be transmitted to the digital signal control chip; and the digital signal control chip synchronously samples the conditioned simulation signals to obtain an AD conversion result and output a rotor position angle value. According to the method, a special calculating chip is removed, so that the integration level of a control system is improved, and the cost of the control system is reduced.

Description

A kind of resolver system and control method thereof

Technical field

The present invention relates to resolver, relate in particular to a kind of resolver system and control method thereof.

Background technology

Resolver is a kind of position transducer based on the electromagnetic coupled principle, and it is a kind of small-sized alternating current machine as angular surveying in essence.Resolver need to add excitation signal as input signal, and it is output as the analog signal of two-way quadrature simultaneously, thereby must obtain by analog-to-digital conversion and computing the digital signal of correspondence position, can be input to control chip.

At present, some special digitals conversion (RDC) chips such as the conversion that the AU6802 of the AD2S1200 of AD company or TAMAGAWA company etc. can finish the generation of resolver excitation signal and output signal to digital type position signal.Cause it expensive but these chips are single-minded owing to performance, purposes is special.

Summary of the invention

The invention provides a kind of resolver system and control method thereof, the present invention has reduced production cost, has satisfied the needs in the practical application, sees for details hereinafter to describe:

A kind of resolver system comprises: resolver, Digital Signals chip and signal conditioning circuit;

The sinusoidal excitation signal of described Digital Signals chip modulation output predeterminated frequency, the rear rated voltage as described resolver of conditioning; The zero passage moment of described sinusoidal excitation signal is as the interrupt signal of described Digital Signals chip; The timer of described Digital Signals chip begins counting as time reference constantly with zero passage, and the described Digital Signals chip of 1/4 all after dates of delaying time gathers the AD sampling of described resolver cosine and sine signal;

Described resolver output two-way sine and cosine modulated analog signal, described signal conditioning circuit is nursed one's health described two-way sine and cosine modulated analog signal, obtains the rear analog signal of conditioning and transfers to described Digital Signals chip;

Described Digital Signals chip to described conditioning after analog signal carry out synchronized sampling, obtain AD transformation result and output rotor position angle value.

Said method comprising the steps of:

When (1) described resolver worked, elementary excitation winding R1-R2 added the sinusoidal voltage E of predeterminated frequency and default amplitude _R1-R2Two-phase secondary induction winding S1-S3, S2-S4 be output voltage E respectively _S1-S3, E _S2-S4

(2) according to the output voltage E of described two-phase secondary induction winding S1-S3, S2-S4 _S1-S3, E _S2-S4Obtain the rotor position of resolver 1.

Described E _R1-R2=E ₀Sin (ω t); E _S2-S4=KE ₀Sin (ω t) sin θ;

E _S1-S3=KE ₀Sin (ω t) cos θ; E ₀Be the sinusoidal excitation voltage magnitude; K is the no-load voltage ratio of resolver;

W is the exciting voltage angular frequency.

Described rotor position is specially:

$\mathrm{\θ}=\arctan \left(\frac{E_{S2-S4}}{E_{S1-S3}}\right).$

The beneficial effect of technical scheme provided by the invention is: the rotor-position that gets access to resolver by the voltage of two-phase secondary induction winding output, this resolver system has saved special use and has resolved chip, has improved the control system integration degree and has reduced the cost of control system; And got access to the rotor-position of resolver by control method, simple to operate, satisfied the needs in the practical application.

Description of drawings

Fig. 1 is the structural representation of resolver of the prior art;

Fig. 2 is that the signal of a kind of resolver provided by the invention system moves towards schematic diagram;

Fig. 3 is the structural representation of a kind of resolver provided by the invention system;

Fig. 4 is the flow chart that rotary transformer angle resolves;

Fig. 5 is the work schematic diagram of interrupt signal;

Fig. 6 is the schematic diagram of arctangent computation;

Fig. 7 is the flow chart of the control method of resolver.

In the accompanying drawing, the list of parts of each label representative is as follows:

1: resolver; 2: the Digital Signals chip;

3: signal conditioning circuit.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, below embodiment of the present invention is described further in detail.

Referring to Fig. 1, Fig. 2 and Fig. 3, a kind of resolver system comprises: resolver 1, Digital Signals chip (DSC) 2 and signal conditioning circuit 3;

The sinusoidal excitation signal of Digital Signals chip 2 modulation output predeterminated frequencies, the rear rated voltage as resolver 1 of conditioning; The zero passage moment of sinusoidal excitation signal is as the interrupt signal of Digital Signals chip 2; The timer of Digital Signals chip 2 begins counting as time reference constantly with zero passage, and the 1/4 all after date Digital Signals chips 2 of delaying time gather the AD sampling of resolver 1 cosine and sine signal;

Resolver 1 output two-way sine and cosine modulated analog signal, 3 pairs of two-way sine and cosines of signal conditioning circuit modulated analog signal is nursed one's health, and obtains the rear analog signal of conditioning and transfers to Digital Signals chip 2;

2 pairs of conditionings of Digital Signals chip rear mold analog signal carries out synchronized sampling, obtains AD transformation result and output rotor position angle value.

Wherein, predeterminated frequency is set according to the needs in the practical application, is generally the 10kHz sinusoidal excitation signal, and this 10kHz sinusoidal excitation signal is through the rated voltage of conditioning to resolver 1 input excitation signal, as the input of resolver 1.

Wherein, the ePWM timer of Digital Signals chip 2 begins counting take ω t=0 as time reference, and the AD sample conversion at time-delay 1/4 all after dates (ω t=pi/2) startup resolver 1 cosine and sine signal realizes the purpose of " peak value sampling " with this.

The two-way sine and cosine modulated analog signal of resolver 1 output must carry out synchronized sampling through the AD ALT-CH alternate channel that can send into Digital Signals chip (DSC) 2 after the conditioning of signal conditioning circuit 3, its input voltage range be 0-3.3V(namely the signal demand after signal conditioning circuit 3 conditionings satisfy the operating voltage of Digital Signals chip 2).Digital Signals chip 2 reads the AD transformation result and carries out arctangent cp cp operation, finally obtains the rotor position angle value.

The model of above-mentioned device is selected according to the needs in the practical application, if the device that can satisfy above-mentioned functions all can, the embodiment of the invention does not limit this.

Referring to Fig. 4, Fig. 5, Fig. 6 and Fig. 7, the control method of a kind of resolver system may further comprise the steps:

101: during resolver 1 normal operation, elementary excitation winding R1-R2 adds the sinusoidal voltage E of predeterminated frequency and default amplitude _R1-R2Two-phase secondary induction winding S1-S3, S2-S4 be output voltage E respectively _S1-S3, E _S2-S4

Change along with the angle theta between rotor and elementary excitation winding, its quantitative relation satisfies:

E _R1-R2＝E ₀·sin(ωt) (1)

E _S2-S4＝K·E ₀·sin(ωt)·sinθ (2)

E _S1-S3＝K·E ₀·sin(ωt)·cosθ (3)

In the following formula with E ₀=10V is the sinusoidal excitation voltage magnitude; ω=2 π f=2 π * 10kHz are the exciting voltage angular frequency; K is that the no-load voltage ratio of resolver is that example describes, and during specific implementation, can also be other value, and the embodiment of the invention does not limit this.

102: according to the output voltage E of two-phase secondary induction winding S1-S3, S2-S4 _S1-S3, E _S2-S4Obtain the rotor-position of resolver 1.

Formula (2), (3) show that the two-way aanalogvoltage of resolver 1 secondary induction winding output is Sine Modulated and the cosine-modulation of rotor position offset of sinusoidal high frequency exciting voltage, have comprised resolver 1 rotor absolute location information in this two-way high frequency modulated analog signal.Formula (2) (3) is divided by, and obtains:

$\frac{E_{S2-S4}}{E_{S1-\mathrm{<figure-callout\; id="3"\; label="S"\; filenames="HDA00002696700800021.png"\; state="\{\{state\}\}">S</figure-callout>}3}}=\frac{K\&CenterDot;E_0\&CenterDot;\sin \left(\mathrm{\&omega;t}\right)\&CenterDot;\sin \mathrm{\&theta;}}{K\&CenterDot;E_0\&CenterDot;\sin \left(\mathrm{\&omega;t}\right)\&CenterDot;\cos \mathrm{\&theta;}}=\tan \mathrm{\&theta;}---\left(4\right)$

By (4) formula as seen: any time resolver 1 output Sine Modulated aanalogvoltage except ω t=0 and ω t=π is the tan of rotor position with the ratio of cosine-modulation aanalogvoltage, does not have direct relation with sinusoidal excitation voltage; Can obtain the resolver rotor-position so only need to carry out arctangent computation to (4) formula:

$\mathrm{\&theta;}=\arctan \left(\frac{E_{S2-S4}}{E_{S1-S3}}\right)$

Simultaneously, drop on ω t=0 and ω t=π place also so that the analog signal of sampling instant comprises the rotor absolute location information to the full extent for fear of sampling time point, the sampling time point of analog signal should be taken at the peak value place of sinusoidal excitation voltage, and namely corresponding ω t=pi/2 and ω t=3 pi/2 are constantly.

The course of work of this resolver system of the following detailed description and control method thereof, see for details hereinafter and describe:

During resolver 1 normal operation, elementary excitation winding (R1-R2) impressed frequency is that 10kHz, effective value are the sinusoidal voltage (E of 7V _R1-R2); Two-phase secondary induction winding (S1-S3, S2-S4) output voltage (E _S1-S3, E _S2-S4) change along with the angle theta between rotor and elementary excitation winding.The sinusoidal excitation Voltage Peak peak value of resolver 1 is 20V.

Described as an example of TMS320F28335 model control chip example by the Digital Signals chip 2(embodiment of the invention, during specific implementation, select the model of chip according to the needs in the practical application, the embodiment of the invention does not limit this) high accuracy pulsewidth modulation (HRPWM) produce the 10kHz sinusoidal excitation signal, through the voltage signal of signal condition to resolver 1 input 0-20V peak value, as the input of resolver 1.

Utilize as far as possible the AD conversion range of Digital Signals chip 2 through the voltage signal of the sine and cosine modulated analog signal after nursing one's health for DC component 1.65V, maximum amplitude 1.5V, its voltage range is limited between the 0.15V to 3.15V, satisfies the area requirement of ADC input voltage 0-3.3V.Sampled value is input in the Digital Signals chip 2 calculates for software.

Software section:

Determine that at first the calculated rate that directly resolve resolver 1 position is to finish one time location compute in the sinusoidal excitation voltage cycle (T=100ns), mainly is divided into three parts:

(1) behind Digital Signals chip 2 electrification resets, at first carries out system initialization work and according to function each peripheral module register is configured.The high accuracy pulsewidth modulation (HRPWM) of Digital Signals chip 2T produces the 10kHz sinusoidal excitation signal.Because DC reference voltage is call parameter in the process of location compute, therefore at first carries out the AD sampling of la tension de reference Uref est and calculate.After reference voltage calculating is complete, enable external interrupt, program enters major cycle, and waits for the interrupt service routine response.

(2) interrupt initial phase with the HRPWM signal constantly as trigger source.After entering interrupt service routine, heavily loaded ePWM module timer count value (CNT=0) also begins to count 25us.Last removing at interrupt routine is interrupted sign, returns major cycle and is waited for the generation of next time interrupting.

(3) in the arctangent computation task program, directly read the ADC transformation result, by operational order digital quantity is converted to floating number.By sine and cosine modulation voltage, reference voltage parameter, the arctangent computation mission subroutine is finished arctangent computation and is determined rotor position angle, and computational methods are shown below:

$\mathrm{\&theta;}=\arctan \left(\frac{U_{\sin }-U_{\mathrm{ref}}}{U_{\cos }-U_{\mathrm{ref}}}\right)$

It will be appreciated by those skilled in the art that accompanying drawing is the schematic diagram of a preferred embodiment, the invention described above embodiment sequence number does not represent the quality of embodiment just to description.

The above only is preferred embodiment of the present invention, and is in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of doing, is equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (4)

1. a resolver system is characterized in that, comprising: resolver, Digital Signals chip and signal conditioning circuit;

The sinusoidal excitation signal of described Digital Signals chip modulation output predeterminated frequency, the rear rated voltage as described resolver of conditioning; The zero passage moment of described sinusoidal excitation signal is as the interrupt signal of described Digital Signals chip; The timer of described Digital Signals chip begins counting as time reference constantly with zero passage, and the described Digital Signals chip of 1/4 all after dates of delaying time gathers the AD sampling of described resolver cosine and sine signal;

Described resolver output two-way sine and cosine modulated analog signal, described signal conditioning circuit is nursed one's health described two-way sine and cosine modulated analog signal, obtains the rear analog signal of conditioning and transfers to described Digital Signals chip;

Described Digital Signals chip to described conditioning after analog signal carry out synchronized sampling, obtain AD transformation result and output rotor position angle value.

2. a control method that is used for a kind of resolver claimed in claim 1 system is characterized in that, said method comprising the steps of:

When (1) described resolver worked, elementary excitation winding R1-R2 added the sinusoidal voltage E of predeterminated frequency and default amplitude _R1-R2Two-phase secondary induction winding S1-S3, S2-S4 be output voltage E respectively _S1-S3, E _S2-S4

(2) according to the output voltage E of described two-phase secondary induction winding S1-S3, S2-S4 _S1-S3, E _S2-S4Obtain the rotor position of resolver 1.

3. control method according to claim 2 is characterized in that,

Described E _R1-R2=E ₀Sin (ω t); E _S2-S4=KE ₀Sin (ω) sin θ;

E _S1-S3=KE ₀Sin (ω t) cos θ; E ₀Be the sinusoidal excitation voltage magnitude; K is the no-load voltage ratio of resolver;

W is the exciting voltage angular frequency.

4. according to claim 2 or 3 described control methods, it is characterized in that described rotor position is specially:

$\mathrm{\&theta;}=\arctan \left(\frac{E_{S2-S4}}{E_{S1-S3}}\right).$

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