A motor jerk detection device and method

Abstract

The present application aims at providing a motor jitter rate detection device and method with simple structure, high collection accuracy and low cost. The device comprises a first operational amplifier (U1), a charge pump (1), a timing capacitor (C1), an output resistor (R1), an integral filter capacitor (C2), a second operational amplifier (U2) and a triode (Q1). The method converts a high-frequency pulse signal into a direct current voltage, uses a voltage value to replace a frequency, converts a frequency change rate into a voltage fluctuation, i.e. converts a high-frequency time domain into a direct current time domain, and uses a charging and discharging characteristic of the timing capacitor to lengthen a jitter phase for easy collection. The method is simple in operation, good in measurement stability and low in cost. The present application is applied to the motor technical field.

Description

TECHNICAL FIELD

[0001] The present application relates to the motor technical field, especially to a motor jitter detection device and method. BACKGROUND

[0002] Motor jitter will accelerate the motor bearing wear, greatly shorten the normal service life of the bearing, at the same time, the motor jitter will make the winding insulation decline. Due to the jitter, the end winding is loose, causing the end winding to produce mutual abrasion, the insulation resistance is reduced, the insulation life is shortened, and the insulation is broken down in severe cases. In addition, the motor jitter will cause damage to the driven machinery, affect the normal work of the surrounding equipment, and emit a lot of noise. In view of this, when the motor jitter occurs, the motor jitter rate needs to be detected to take corresponding measures to suppress.

[0003] For the motor used in the printer, in the prior art, the printer motor jitter detection generally adopts a high-precision encoder connected with the motor in a soft manner. The rotation characteristics of the motor are fed back to the encoder without affecting the rotation of the motor. The frequency multiplication function of the encoder is used to convert each rotation of the motor into a plurality of pulses, and then the rotation error is calculated by collecting each pulse width.

[0004] However, the current technology has the following disadvantages: there is a contradiction between the collection accuracy and the cost. Since the encoder divides each circle into 1000 pulses (the accuracy is guaranteed), the rotation frequency is expanded by 1000 times (if the motor working speed is 50k / min, the frequency generated by the encoder is 1MHz), and the collection is equivalent to converting the time domain waveform into a discrete domain. The higher the collection speed, the closer the discrete domain to the time domain waveform. However, the higher the collection speed, the hardware cost will increase exponentially (for example, according to 60 collection points per pulse period, the sampling rate needs to be at least 60 meg / s, and the cost is too high). If the ordinary collection speed is 500k / s, it is almost impossible to sample. The fluctuation rate itself is a percentage order, and the unit is very small. The error of nanosecond collection will be amplified by hundreds of times. It is difficult to meet the measurement repeatability. SUMMARY

[0005] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art, and to provide a motor jitter detection device with simple structure, high collection accuracy and low cost.

[0006] The present application also provides a motor jitter detection method, which is simple in operation, good in measurement stability and low in cost.

[0007] The technical scheme of the motor jitter detection device is as follows: the motor jitter detection device comprises a first operational amplifier, a charge pump, a timing capacitor, an output resistor, an integral filter capacitor, a second operational amplifier and a triode, the negative input pole of the first operational amplifier is grounded, the positive input pole is connected with the pulse signal of an encoder, the output pole of the first operational amplifier is connected with the charge pump, one end of the timing capacitor is connected with the charge pump, the other end of the timing capacitor is grounded, the output resistor and the integral filter capacitor are connected in parallel and then connected with the charge pump, the other end of the output resistor is grounded and provided with a zero-speed voltage feedback interface, the other end of the integral filter capacitor is grounded, the parallel connection point of the output resistor and the integral filter capacitor is connected with the positive input pole of the second operational amplifier, the negative input pole of the second operational amplifier is connected with VCC, the output pole of the second operational amplifier is connected with the base pole of the triode, the collector pole of the triode is connected with VCC, the emitter pole of the triode is grounded through a second resistor and provided with a direct current output interface.

[0008] The above scheme shows that the first operational amplifier, the charge pump, the second operational amplifier, the triode, the timing capacitor, the output resistor and the integral filter capacitor are cooperatively arranged, wherein the first operational amplifier receives the pulse signal input of the encoder, the charge pump converts the input pulse signal into a direct current voltage, has a frequency multiplication function for low ripple, the charging and discharging characteristics of the timing capacitor lengthen the jitter phase, facilitate collection, the output resistor is used as a load resistor, the integral filter capacitor filters and integrates the current to obtain a voltage, the triode plays a role of amplifying a signal, controlling a current, switching and protecting a circuit, the negative input pole of the first operational amplifier is grounded, and the negative input pole of the second operational amplifier is connected with VCC, which ensures that the device will not be damaged by input signals higher than Vcc or lower than the ground reference point; when the zero frequency input, the output voltage can be adjusted according to the resistance value; therefore, the application has simple structure, low cost and high collection accuracy.

[0009] Further, the first operational amplifier is a floating triode, and the output current is 50mA at most. As can be seen, the floating triode can convert the pulse signal into a current signal.

[0010] Further, the capacitance value of the timing capacitor is greater than 500pF. As can be seen, the timing capacitor can provide internal compensation for the charge pump, and the value is set to be greater than 500pF in order to obtain accurate conversion results. Too small capacitance value will generate an error current on R1.

[0011] The method for detecting the motor jitter rate by using the above detection device comprises the following steps:

[0012] a, the frequency of the pulse signal connected with the positive input pole of the first operational amplifier is fin , the capacitor value of the timing capacitor is C1, the resistance value of the output resistor is R1, the capacitor value of the integration filter capacitor is C2, and the charge pump converts the frequency input from the input terminal of the first stage operational amplifier into a direct current voltage output;

[0013] b. When the state of the output of the first stage operational amplifier changes, the timing capacitor is linearly charged or discharged between the two voltage values of the voltage difference Vcc / 2, and in the half cycle of the input frequency signal, the amount of charge change on the timing capacitor is C1*Vcc / 2, and the average current pumped into the timing capacitor or the average current flowing out of the capacitor is:

[0014] I C1 =f in *C1*Vcc;

[0015] c. The above current I C1 is accurately sent to the output resistor, and the filtered current is integrated by the integration filter capacitor to obtain the output voltage Vo as:

[0016] Vo=Vcc*f in *C1*R1*K,

[0017] where K is a gain constant, and the value is 1. The linear voltage output has a linear relationship with the input pulse frequency as:

[0018] V OUT =Vcc*f in *C1*R1;

[0019] d. The rate of change of the frequency of the pulse signal of the encoder is converted into the fluctuation of the voltage, and the rate of change of the frequency is the jitter rate of the motor.

[0020] The above scheme shows that the high-frequency pulse signal is converted into a direct current voltage, the frequency is replaced by the voltage value, the jitter rate is the rate of change of the frequency, the rate of change of the frequency is converted into the fluctuation of the voltage, that is, the high-frequency time domain is converted into the direct current time domain, and the jitter phase is lengthened by the charging and discharging characteristics of the timing capacitor, which is convenient for collection. The method is simple to operate, has good measurement stability, and is low in cost.

[0021] Further, the value of the integration filter capacitor depends on the size of the ripple voltage, where the ripple voltage V RIPPLE is calculated using the following formula:

[0022] V RIPPLE =(Vcc / 2)*(C1 / C2)*[1-(Vcc*f in *C1 / I2)],

[0023] where I2 is the current of the second resistor.

[0024] The above scheme can see that the voltage calculation of the ripple can effectively avoid the influence of the ripple on the detection result. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is the circuit schematic diagram of the motor jitter detection device of the present application. DETAILED DESCRIPTION

[0026] As Figure 1 shown, the motor jitter detection device of the present application comprises a first-stage operational amplifier U1, a charge pump 1, a timing capacitor C1, an output resistor R1, an integral filter capacitor C2, a second-stage operational amplifier U2, and a triode Q1, the negative input pole of the first-stage operational amplifier U1 is grounded, the positive input pole is connected to the pulse signal of an encoder, the output pole of the first-stage operational amplifier U1 is connected to the charge pump 1, one end of the timing capacitor C1 is connected to the charge pump 1, the other end of the timing capacitor C1 is grounded, the output resistor R1 and the integral filter capacitor C2 are connected in parallel and then connected to the charge pump 1, the other end of the output resistor R1 is grounded and provided with a zero-speed voltage feedback interface, the other end of the integral filter capacitor C2 is grounded, the parallel connection point of the output resistor R1 and the integral filter capacitor C2 is connected to the positive input pole of the second-stage operational amplifier U2, the negative input pole of the second-stage operational amplifier U2 is connected to VCC, the output pole of the second-stage operational amplifier U2 is connected to the base pole of the triode Q1, the collector pole of the triode Q1 is connected to VCC, the emitter pole of the triode Q1 is grounded through a second resistor R2 and provided with a direct-current output interface.

[0027] The first-stage operational amplifier U1 is a floating triode, which outputs a maximum of 50mA of output current. The hysteresis voltage of the first-stage operational amplifier U1 is 30mV, which can be used to suppress external interference, the output voltage is proportional to the input frequency, and the linearity is ±0.3%.

[0028] The capacitance value of the timing capacitor C1 is greater than 500pF. The timing capacitor C1 can provide internal compensation for the charge pump. In order to obtain accurate conversion results, the value is set to be greater than 500pF. Too small capacitance value will produce error current on R1, and the linearity of frequency / voltage conversion will also be poor.

[0029] The method for detecting the motor jitter rate by using the above motor jitter detection device comprises the following steps:

[0030] a. The frequency of the pulse signal connected to the positive input pole of the first-stage operational amplifier U1 is f in , the capacitance value of the timing capacitor C1 is C1, the resistance value of the output resistor R1 is R1, the capacitance value of the integral filter capacitor C2 is C2, and the charge pump 1 converts the frequency input from the input pole of the first-stage operational amplifier U1 into a direct-current voltage output;

[0031] b、When the state of the first-stage operational amplifier U1 output changes, the timing capacitor C1 is linearly charged or discharged between the two voltage values of voltage difference Vcc / 2, and in the half cycle of the input frequency signal, the charge variation amount on the timing capacitor C1 is C1*Vcc / 2, and the average current pumped into the timing capacitor 1 or the average current flowing out of the capacitor is:

[0032] I C1 =f in *C1*Vcc;

[0033] c、The above current I C1 is accurately sent to the output resistor R1, and the filtered current is integrated by the integral filter capacitor C2 to obtain the output voltage Vo as:

[0034] Vo=Vcc*f in *C1*R1*K,

[0035] Wherein, K is a gain constant, and the value is 1, and the linear voltage output is linearly related to the input pulse frequency as:

[0036] V OUT =Vcc*f in *C1*R1;

[0037] d、The change rate of the frequency of the pulse signal of the encoder is converted into the fluctuation of the voltage, and the change rate of the frequency is the jitter rate of the motor.

[0038] The value of the integral filter capacitor C2 depends on the size of the ripple voltage, wherein the ripple voltage V RIPPLE is calculated by the following formula:

[0039] V RIPPLE =(Vcc / 2)*(C1 / C2)*[1-(Vcc*f in *C1 / I2)],

[0040] Wherein, I2 is the current of the second resistor R2.

[0041] The present application converts the high-frequency pulse signal into a direct-current voltage, uses the voltage value to replace the frequency, and converts the jitter rate into the change rate of the frequency, and converts the change rate of the frequency into the fluctuation of the voltage, that is, converts the high-frequency time domain into the direct-current time domain, and uses the charging and discharging characteristics of the timing capacitor to lengthen the jitter phase, and facilitates collection.

[0042] Suppose that the frequency is ideal and has no jitter, then the output is a straight line, and if the frequency has jitter, then the output is a straight line with burrs.

[0043] Finally, it should be noted that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A motor jerk detection device, characterized by, It includes first stage operational amplifier (U1), charge pump (1), timing capacitor (C1), output resistor (R1), integral filter capacitor (C2), second operational amplifier (U2), triode (Q1), the negative input of the first stage operational amplifier (U1) is grounded, the positive input is connected to the pulse signal of the encoder, the output of the first stage operational amplifier (U1) is connected to the charge pump (1), one end of the timing capacitor (C1) is connected to the charge pump (1), the other end of the timing capacitor (C1) is grounded, the output resistor (R1) and the integral filter capacitor (C2) are connected in parallel and then connected to the charge pump (1), the other end of the output resistor (R1) is grounded and provided with a zero speed voltage feedback interface, the other end of the integral filter capacitor (C2) is grounded, the parallel connection point of the output resistor (R1) and the integral filter capacitor (C2) is connected to the positive input of the second operational amplifier (U2), the negative input of the second operational amplifier (U2) is connected to VCC, the output of the second operational amplifier (U2) is connected to the base of the triode (Q1), the collector of the triode (Q1) is connected to VCC, the emitter of the triode (Q1) is grounded through a second resistor (R2) and provided with a DC output interface.

2. A motor jerk detection device according to claim 1, characterized in that The first stage operational amplifier (U1) is a floating triode, which outputs a maximum of 50mA of output current.

3. The motor jerk detection apparatus of claim 1, wherein The capacitance value of the timing capacitor (C1) is greater than 500pF.

4. A method of detecting a motor ripple using the motor ripple detection apparatus according to claim 1, characterized by, The method comprises the following steps: a、Set the first stage of the operational amplifier (U1) positive input terminal access encoder pulse signal frequency f in , timing capacitor (C1) of the capacitor value is C1, the output resistance (R1) of the resistance value is R1, the integral filter capacitor (C2) of the capacitor value is C2, the charge pump (1) from the input of the first stage of the operational amplifier (U1) input frequency conversion into a direct current voltage output; b. When the state output by the first stage operational amplifier (U1) changes, the timing capacitor (C1) is linearly charged or discharged between two voltage values of voltage difference Vcc / 2, and in a half cycle of the input frequency signal, the charge change amount on the timing capacitor (C1) is C1*Vcc / 2, and the average current pumped into the timing capacitor (C1) or the average current flowing out of the capacitor is: I C1 = f in *C1*Vcc; c. the current I C1 is accurately fed to the output resistor (R1), the filtered current is integrated by the integrating filter capacitor (C2) and the output voltage Vo is obtained as Vo = Vcc * f in *C1 * R1 * K, Wherein, K is a gain constant, and the value is 1, and the linear voltage output is linearly related to the input pulse frequency as follows: V OUT = Vcc * f in *C1*R1; d. The frequency change rate of the pulse signal of the encoder is converted into voltage fluctuation, and the frequency change rate is the jitter rate of the motor.

5. The method of claim 4, wherein, The value of the integrating filter capacitor (C2) depends on the size of the ripple voltage, where the ripple voltage V RIPPLE The following formula is used for the calculation: V RIPPLE = (Vcc / 2) * (C1 / C2) * [1 - (Vcc*f in *C1 / I2)], Wherein, I2 is the current of the second resistor (R2).

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