TWI279551B - Voltage measurement apparatus for filter module with adjustable planarity - Google Patents

Abstract

A voltage measurement apparatus includes a filter module, an AC-DC converter module, and a digital signal processing module. The filter module can accept an AC voltage being measured from a first input terminal, then going through the first output end by attenuating and filtering the signal from said AC voltage. The AC-DC converter module can accept the AC voltage of the first output terminal, and transforming AC voltage into DC voltage in which the RMS value is the equivalent DC value of the AC voltage being measured. The digital signal processing module accepts the DC voltage which output form AC-DC converter, and said DC voltage can be transformed into a corresponding digital signal. Moreover, the digital signal processing module can put out a pulse width modulated signal and a control signal to the AC filter module.

Description

J279551, IX. Description of the Invention: [Technical Field] The present invention relates to a measuring device, and more particularly to a voltage measuring device. [Prior Art] Referring to FIG. 1, a conventional voltage measuring device includes an AC filter module 6, an AC to DC voltage module 7, a digital signal processing module 8, and a microprocessor 9. The AC filter module 6 is electrically connected to the microprocessor 9 and the AC-DC voltage module 7, and the digital signal processing module 8 is electrically connected to the AC-DC voltage module 7. The AC filter module 6 receives the AC voltage to be tested by a first input terminal AC_IN, and attenuates the component of the AC voltage to be tested whose frequency is above 3〇〇KHz, and simultaneously measures the to be measured. The component of the AC voltage whose frequency is below 300KHZ is appropriately attenuated and then amplified to become an AC voltage with a root mean square of 2V or less, and is output to the AC to DC voltage via a first output terminal AC to OUT. The module 7 is adapted to meet the maximum resolution of the AC to DC voltage module 7 of 2V. After receiving the AC voltage of the first output terminal AC_〇UT, the DC-to-AC voltage module 7 can convert it into a DC voltage equal to the rms value of the AC voltage to be tested. The digital signal processing module 8 receives the DC voltage and outputs a measured value relative to the DC voltage value to a display (not shown) to display the value of the AC voltage to be tested. The parent-child filter module 6 includes an AC filter circuit 6A, a first amplification circuit 62, and a second amplification circuit 63. The AC filter circuit 61 includes 1279551 complex capacitors Cp2 to Cp6, complex resistors r2, r4 to r6, r9 to rlO, H2 to rl3, an operational amplifier (〇P Amplifier) OP1, and a complex analog switch (Kn1, U1). The first amplifying circuit 62 includes a resistor r8, a ten-fold amplification unit 621, and a plurality of analog switches U2 to U5. The ten-fold amplification unit 621 has an operational amplifier 〇P2, a resistor rl and a variable resistor r3. The second amplifying circuit 63 includes an operational amplifier OP3, a resistor r7, a variable resistor r11 and a capacitor Cpl. The analog switches K1, U1~U5 are controlled by the microprocessor 9, and are switchable between a closed and an open position, and the resistors rl~r13 are precision resistors. The AC filter circuit 61 can appropriately attenuate the component of the AC voltage to be measured having a frequency below 3OOKHz, and then amplify it and send it to the first amplifier circuit 62. The ten-fold amplification unit of the first amplifying circuit 62 can amplify the voltage received by the analog switch U2 by a factor of ten. The second amplifying circuit 63 can amplify the voltage received by the analog switches U3 to U5 by a factor of two to the first output terminal AC_OUT. When the range of the AC voltage to be measured is the parent voltage of the rms value lv~1〇v, the microprocessor 9 sets the analog switches K1 and U5 to be turned off, and the analog switches U2~ U4 is turned on, so that the inverting input terminal of the operational amplifier OP1 is electrically connected to the output end thereof, and the input impedance value of the operational amplifier OP1 is extremely high, and the operational amplifier 〇ρι is used as a buffer, so the alternating current filter circuit 61 The gain value (gai... is 丨, the test 乂: the electric C is equal to the output voltage of the 4-transistor amplifier QP1 is sent to the first amplifying circuit 62. To obtain the maximum resolution, the microprocessor 9 sets the analog switch U5. Turning off the first-amplifying circuit 62, the rms value of the rms value is controlled by 1279551, and the voltage to be tested is attenuated by the voltage r8 by a factor of 1 to become a voltage of the root mean square of 2 IV or less, and is fed to the second amplifying circuit. M. The second amplifying circuit is then amplified by a factor of 2 and becomes a voltage having a root mean square value within 2v, which is sent to the AC to DC voltage module 7. The equivalent rms value (UV~1V) When the AC voltage to be tested is the same, the micro Reason 9 Set the material analog ratio _ Ki, m, u4 off, =: and other analog switches U2, U3, U5 are set to ON. The operational amplifier 〇P1 of the AC wave circuit Q is still used as a buffer to use the output of the operation "0P1" The voltage is equal to the AC voltage to be tested, and is sent to the first-=large circuit 62. The first-amplifier circuit 62 directly sends the AC to be tested to the amplifying circuit 63 of the brother 1 to amplify 2 times to become a root mean square value range. The parental voltage below 2V is re-entered into the AC-DC circuit 7. In the AC voltage range below the rms 1·1ν, the analogy _mU3 is turned off and the switch U4, U5 The shirt is turned on. The ==〇P1 of the AC circuit 61 is similarly used as a buffer. The output of the operational amplifier is equal to the AC house to be tested, and the first amplification is performed. The multiplying unit amplifies the electric power received by the analogy by 10 times and then sends it to the second amplifying circuit 63 and then puts an alternating voltage having a root mean square value below ... and sends it to the parent> 7. In the case of the above three measurement ranges, The AC filter circuit μ=the different amplifier 〇P1 is used as a buffer, so the AC voltage gain value of the AC data circuit has a frequency attenuation of the parent current voltage of any frequency 1279551, so the AC filter circuit 61 The AC voltage to be tested with a rms value of 10 V or less has no filtering effect at all. When the rms value of 10 V to 100 V and the AC voltage to be tested of 100 V to 750 V are measured, 'the analog switches K1 and U1 are turned on at this time. The AC voltage to be tested is input from the inverting input terminal of the operational amplifier OP1 of the AC filter circuit 61. Therefore, the operational amplifier 〇P1 is used as an inverting amplifier, and the gain value of the AC filter circuit 61 is _ri〇/( Ri2+rl3)=-0.01, so the AC voltage to be tested will be attenuated by 100 times, and the output terminal of the operational amplifier OP1 is sent to the first amplifying circuit 62 and the second amplifying circuit 63, and the microprocessor 9 is The analog switches U2 to U5 are appropriately set so that the voltage of the first output terminal AC_OUT can reach the maximum resolution of the AC-DC voltage module 7. However, since the AC filter circuit 61 has a characteristic of a gain-to-gain ratio, that is, when the gain is increased, the bandwidth is reduced, and the attenuation of the AC voltage having a higher frequency is greater than 100 times (-40 db). The Bode diagram of FIG. 2 shows the relationship between the frequency and the gain value of the AC voltage in the frequency range of 3OOKHz by the AC filter circuit 61. The frequency response diagram of the AC filter circuit 61 shows that the higher the frequency, the curve of the gain value decreases. . For the AC voltage with the frequency below 300KHZ, it is attenuated by -40db; but the m2 point shows that the gain value of the frequency response curve is attenuated to -40.478db at 300KHz, and the attenuation value is attenuated when the bandwidth is 10MHz. _61db. The AC filter module 6 of the conventional voltage measuring device attenuates the _40.478 db for the AC voltage having a frequency of 300 kHz, and the flatness of the loss bandwidth within 3 〇〇khz, so that the bandwidth cannot reach 300 kHz. To improve the bandwidth of 1279551 -300 ΚΗζ _ flatness, the resistor r6 and capacitor cp4 must be adjusted to increase the bandwidth, and the consistency of each voltage measuring device can be maintained in mass production. Accurate resistance and capacitance values increase the bandwidth and match the chopping effect while maintaining consistency. At present, high-accuracy resistors and capacitors on the market are quite expensive. As described above, when the AC wave module 6 in the conventional voltage measuring device measures the AC voltage below the root mean square value H)V, there is no chopping effect at all. '❿Measure the root mean square value of 100V. And the AC material of 75 〇v is affected by the characteristics of the gain bandwidth ratio of the AC wave circuit 61, so that the bandwidth is reduced to 300 KHz, and the filtering effect is not good. Furthermore, in order to increase the bandwidth and maintain the consistency of the filtering effect, it is necessary to adjust the resistance value and the capacitance value quite accurately in order to increase the bandwidth, and it is necessary to have a high resistance value and a capacitance value in order to increase the bandwidth and maintain the filtering effect. _ To the sex. Highly accurate resistors and capacitors are expensive and practical. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a voltage measuring device that has a bandwidth of up to 3 G (KHz) and does not require high-accuracy resistance values and capacitance values. It can meet the flatness of the gain value in the bandwidth and maintain the consistency of each voltage measuring device. Therefore, the electrical measuring device of the present invention comprises an AC filter module capable of adjusting a flat twist, an AC to DC_group and a digital signal secondary module. The AC chopper module with adjustable flatness has a first input end and a first output end for receiving the voltage of the 1279551 to be tested, and the signal can be appropriately attenuated and waved after the wave to be tested. , output through the first output. The AC-to-DC voltage module is electrically connected to the AC filter module, and can receive the first round of the hexagram, the ☆+, and the electromechanical £, and can convert the AC voltage into a voltage value. A DC voltage equal to the rms value of the AC voltage at the first output terminal. The signal processing module can receive the DC voltage 'outputted by the AC to DC voltage module' and change the DC voltage according to the measurement range in which it is located to a measured value corresponding to the AC voltage to be tested, and A pulse width modulation signal and a control signal can be rotated to the AC filter and wave module. The pulse width of the pulse width modulation signal is equal to the error value of the measured value and the average value of the AC voltage to be tested, so that the AC wave module can adjust the output voltage of the output terminal. The control signal can control the AC filter group to be attenuated by the first output terminal when the voltage is measured in different voltage measurement ranges. The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments. Referring to Figures 3 and 4, a preferred embodiment of the voltage measuring device of the present invention comprises an AC filter module 1 having an adjustable flatness, a digital signal processing module 3 and a parent DC DC voltage module 2. The digital signal processing module 3 is electrically connected to the alternating current filter, the wave module 1 and the alternating current to direct current voltage module 2, and the alternating current filter module 1 has a receiving AC power to be tested 10 1279551 The first input terminal ac_in is pressed, and the voltage to be tested is appropriately L-shaped and filtered, and then sent to the AC-DC voltage module 2 via a first output terminal Ac_〇xjt, so that the The voltage of the first output terminal AC_〇UT is within the maximum resolution of the AC to DC voltage module 2: the AC to DC voltage module 2 can receive the first output AC_OUT “AC voltage” and can exchange the AC The voltage is converted into a DC voltage having a voltage value equal to the rms value of the AC voltage of the first output terminal AC_〇UT, and is sent to the digital signal processing module 3. The digital signal processing module 3 can receive the DC power output of the AC to DC voltage module 2, and convert the DC power according to the measurement range into a

The AC voltage to be tested corresponds to the measured value, and is output to a display (not shown) and can output a pulse width modulation signal pwM and a control signal to the AC mode, group i, the pulse The pulse width of the width modulation signal pwM is proportional to the error value of the measured value and the root mean square value of the AC to be tested, so that the AC filter module 1 adjusts the first output terminal AC_OUT The output voltage, the control signal can control the AC filter module i to appropriately attenuate the AC voltage to be tested when being measured in different voltages, and then output the AC output from the first output terminal AC-OUT. 踗; The chopper module 1 includes an AC chopper circuit, a flatness adjustment circuit 13, a compensation circuit 14, and an amplifying circuit 12. The interfering circuit u can receive the AC nickname FLATNESS ADJ to be tested. Externally, ...,, - After the voltage to be tested is appropriately deducted and filtered, a first ^ #义弟胡匕〇 is outputted to the amplifying circuit 12, and a first 跋F is outputted Ba Le 仏 %%% partial pressure and filter after the repair The signal 1279551 is sent to the flatness adjustment circuit 13 to enable the flatness adjustment circuit Η to sample the voltage of the first signal. The amplifying circuit 12 is electrically connected to the AC-DC voltage module 2 via the first output terminal AC-OUT. Connected, and the first signal ^c/ can be appropriately amplified and output to the first output terminal AC_OUT. The compensation circuit 14 can receive the pulse I degree modulation signal output by the digital signal processing module 3. And outputting a compensation signal to the flatness adjustment circuit 13, the voltage value of the compensation signal is inversely proportional to the pulse width of the pulse width modulation signal PWM. The flatness adjustment circuit 13 receives the compensation signal and the correction signal. The calibration signal FLATNESS_ADJ can be output to the AC filter circuit u, and the calibration signal FLATNESS_ADJ can adjust the first signal of the AC filter circuit. The AC wave circuit 11 includes a first operational amplifier ai, a first Capacitor C1, - second capacitor C2, a third capacitor 〇, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor π, a resistor R1, a second resistor R2, a first Two a wide resistance R3, a fourth resistor R4, a fifth resistor R5, a sixth electric spear, a resistor R6, a seventh resistor R7 and a first switch S1. The first operational amplification A 1 Xi X h aborigines The positive phase input terminal of the benefit A1 is grounded, and the complex inverting input terminal and one end of the fifth resistor R5, /, the inverting wheel and the fourth capacitor C4 of the ?H, one end of the second capacitor C2, The flute „日日石海^°Haidi one switch S1 one end, the life Chu Yuyu C6 one end and the second resistor R2 /, the capacitor electric I ug one end electrically connected the first signal 匕c/ And the turn-out end can be the same as the six-reactor, such as the _ terminal % channel 12, the third resistor R3, a μ amplification, the second resistor R2, the other end 12 1279551 :: Hai: five capacitor C5 One end and one end of the first resistor R1 are electrically connected to the other end of the resistor/6, and the other end of the resistor R6 is electrically connected to the end of the flatness adjusting circuit 13 and the seventh resistor R7, and the correction signal can be output. The other end of the seventh resistor R7 is a ground voltage. 4, the seventh electric valley C7 is connected in parallel with the sixth resistor R6, the other end of the fourth capacitor is electrically connected to the end of the third capacitor C3 and one end of the fourth electric 35R4, and the third capacitor C3 is another One end of the third input R3 is electrically connected to the other end of the sixth capacitor, and the other end of the fifth capacitor C5 is opposite to the other end of the first switch si. One end of a capacitor C1 and the other end of the first resistor R1 are electrically connected, and the other end of the second capacitor C2 is electrically connected to the other end of the first capacitor C1 and can receive the calibration signal FLATNess_adj. The other end of the fourth resistor R4 is electrically connected to the other end of the fifth resistor R5. The amplifying circuit 12 includes a second switch S2, a third switch, a fourth switch S4, a fifth switch S5, a sixth switch%, a first discharge unit 121, an amplification unit 122, and a buffer unit. ^23. One end of the second switch S2 is electrically connected to the AC filter circuit n, and can receive the first signal 匕c/, and the other end is electrically connected to the first amplifying unit 121. The first amplifying unit 121 receives the first signal Gc/ via the second switch S2, and can amplify the first signal by a factor of 1 to become a second L number. One end of the fifth switch S5 is electrically connected to the alternating current filter circuit ,, and can receive the first signal, and the other end is electrically connected to the two amplifying units. One end of the sixth switch S6 is electrically connected to the first amplifying unit 121, and can receive the second signal, and the other end is electrically connected to the 1331307951 two amplifying unit m. The second amplifying unit i22 can receive the first signal ^ via the cough, and can receive the second signal ~2 via the sixth switch %, and can amplify the signals by 10 times to become - third. The end of the fourth switch 84 of the nickname Fw is electrically connected to the AC slot circuit and can receive the first signal 匕. And the other end is electrically connected to the buffer unit 123. One end of the third switch S3 is electrically connected to the second amplifying unit, and can receive the third signal ^, and the other __ terminal is electrically connected to the buffer. The buffer unit (2) can receive the 5th-signal~ via the four switches, and can receive the third signal ' via the third switch s3, and can output the signals to the first output AC-OUT . The switches S1 S S6 can be controlled to be turned on or off by a control signal output from the digital signal processing module 3. The first amplifying unit 121 includes a fourteenth resistor phantom 4, a fifteenth resistor R15, a +^, a resistor R16 and a second operational amplifier A2. One end of the fourteenth resistor R14 is electrically connected to the positive terminal of the second switch and the second operational amplifier A2. The other end of the fourteenth resistor R14 is connected: the fifteenth resistor R15 Connected between the ground voltage and the second operation from the inverting input end of the amplifier A2, the sixteenth resistor 跨 $ is connected to the inverting input end and the output end of the second amplifier A2 Between the output of the second blade and the output of the second switch is electrically connected to the sixth switch and output the second signal. 〆 The first magnification unit! 22 includes a seventeenth resistor Ri7, an eighteenth, a Chuanchuan, a 'thirteenth resistor R19, and a third operational amplifier A3. The first phase input terminal of the first amplification state A3 and the fifth switch Μ and the 14th 1279551 are connected, the seventeenth resistor R17 is connected to the ground potential and the positive phase wheel of the rJ:: 'amplifier A3 Between the input terminals, the eighteenth resistor ground potential and the inverting input terminal of the third operational amplifier A3 are connected to the opposite end of the third operational amplifier A3. The output terminal of the third operational amplifier 可 can be connected to the third switch and electrically connected to the third switch. /, 友冲单疋123 includes a fourth operational amplifier A4, a tenth electric (10), a tenth-capacitor C11, a twenty-first resistor R21 twenty-resistance R20. Continued ® This two - a cry ° One of the electric CU one end, the fourth operational amplification i the first round of the human end and the twentieth resistance (four) - the end of the electrical connection, = * CU the other end and the fourth The switch S4 and the third switch are electrically connected, and the inverting input end of the fourth operational amplifier $A4 is electrically connected to one end of the second eleventh yang + resistor R21, and the twentieth R20 The other end is a ground voltage, the twentieth-electric P and the other end of R21 is the first-output AC_0UT, and the tenth capacitor C10 is connected across the two twentieth-resistors R21. The flatness adjustment circuit 13 includes a fifth operational amplifier Al§ A5, an eight electric valley C8, an eighth resistor R only, a spear resistor R8, a young nine resistor R9, an adding unit m, and an electric_variable Resistor unit 132. The adding unit 13 is electrically connected to the compensation circuit, and is connected to the (4) compensation signal, and outputs the compensation signal to the DC dust level to be an impedance adjustment signal. The positive phase wheel terminal of the fifth operational amplifier A5 receives the correction signal ', and the inverting wheel terminal is electrically connected to the ninth resistor, and the output terminal outputs the reference signal _ADJ' The eighth capacitor α and the eighth resistor 15 1279551 R8 are connected across the fifth operational amplifier, and the other end of the ninth resistor R9 between the inverting input terminal and the output terminal of the A5 and the voltage control variable resistance unit 1 The first end 1321 is electrically connected. The first terminal 1322 of the voltage control variable resistance unit is electrically connected to the adding unit 131 and receives the impedance adjustment ^ and /, and the ground is electrically connected. The resistance of the electric control variable resistor between the first end and the third end of the early 70 132 can be reduced by changing the voltage of the second end. In a preferred embodiment of the present invention, the voltage-controlled variable resistor single-it 132 is a Ν-type channel field effect transistor (FET), but the addition unit 131 does not include a sixth operational amplification capacitor C9. A tenth resistor R1〇, an eleventh resistor core, a tenth=R12 and a thirteenth resistor illusion 3. The sixth operational amplifier is electrically connected to the end of the thirteenth resistor R13 and the twelfth resistor, and the inverting input terminal and the eleventh resistor M1 are Ten lightning / 3⁄4 > anti-listening - Γ end electrical connection, and its output terminal outputs the resistance s and is electrically connected to the other end of the tenth resistor R10, the other end of the electric 16R13 is grounded Electric M, the other end of the twelfth resistor (10) t is lightly coupled to a -g ^ + φ 贞 15V_voltage source, and the ninth capacitor C9 is connected across the tenth of the tenth electric power (four) to the tenth compensation signal. The r resistor as the other end receiving z compensation circuit 14 includes a seventh operational amplification capacitor C12, a second + eleven eleven electric ^ one electric valley C13, a fourteenth capacitor C14, a first - + two resistor R22 One, the first - the first one is not the same as the second + - thousand - twelve resistors and - the twenty-fourth resistor R24. One or two electric & R23 - end and (four) fourteen capacitor C14 - end and 16 1279551

-x the fourth end of the fourteenth resistor R24 is electrically connected, and the other end and the tenth, the one end of the electric: C12 and one end of the twenty-second resistor R22 are electrically connected to the other end of the fourteen resistor R24 Receiving the pulse width modulation signal, the other end of the fourteenth electric valley C14 is grounded, and the other end of the twelfth capacitor C12 is electrically connected to the inverting input end and the output end of the seventh operational amplifier A7. The twenty-second electric power p and the other end of the R22 are amplified by the seventh operation: the positive phase wheel of the soil 7 and one end of the thirteenth capacitor (3) are electrically connected, and the other end of the twelfth capacitor C13 is the ground voltage. . The AC filter circuit 11 and the amplifying circuit 12 must appropriately adjust and filter the voltage to be tested received by the first input terminal /C-IN so that the voltage of the first output terminal AC-UT is squared. The root value is within 2V. The first resistor R1, the third resistor R3, the sixth power and R6, the seventh resistor, the fifth capacitor C5, the sixth capacitor C6, and the seventh device C7 The circuit has a filtering effect, so that all measurement ranges = the AC voltage to be tested can be attenuated by more than 3 于 at a frequency of 8 MHz. The two capacitors C4 are connected across the fourth resistor R4 and the fifth resistor R5 to increase the bandwidth of the /over-wave circuit 11 to 300 kHz. When the voltage of the rms value is less than 11V, the digital signal is: the module 3 sets the second switch S2, the third switch S3 and the sixth switch % to be off, and The first switch S1, the fourth switch S4 and the fifth switch are "on", and the first operational amplifier A1, the second resistor R2, the fourth electrical two R4 and the fifth resistor R5 form a gain value of one and a pool + magic _〇2 (In the present example, 'adjust the values of the second, fourth, and fifth resistors R2, R4, and R5 so that the gain is -0.2, but not limited thereto), and the voltage to be tested is attenuated by 5 Times

17 1279551 becomes the first signal of δhai. The first signal ^C/ is sent to the first amplifying unit 21 to be amplified by 1〇 and becomes a second signal Gc within the root mean square value 〇·2ν, and then amplified by the second amplifying unit 122 by 1〇 times. The third signal within 2V of the rms value is outputted by the buffer unit 123 to the first round-out terminal AC_OUT. When the rms value of the RMS is between 0.1V and IV, the digital signal processing module 3 sets the third switch S3 and the fifth switch S5 to be off, and • the first switch S1 The second switch S2, the fourth switch S4, and the sixth switch S6 are turned on. Similarly, the circuit composed of the first operational amplifier A1, the second resistor R2, the fourth resistor R4, and the fifth resistor R5 can attenuate the "Hui/wait voltage by 5 times to become the first signal^ . The first signal dc / 11 to 忒 the amplifying unit 122 is amplified by a factor of 1 and becomes a second signal G port within the root mean square value 2ν, and then outputted by the buffer unit 123 to the first output terminal AC_OUT 〇 ^The equivalent rms value is at a voltage of IV~10V, the digital signal processing % modulo, and 3 sets the "Hai fourth switch S4 to off, and the first switch s J, the first switch S2, the third switch S3, the fifth switch S5, and the sixth switch %, in the same manner, the circuit of the first operational amplifier A1, the second resistor R2, the first resistor R4 and the fifth resistor R5, The electric power to be tested can be attenuated by 5 times to become the first signal within the rms value of 2V. The first 佗唬GC/ is sent to the buffer unit 123 and output to the first output terminal AC_OUT. When the rms value is set to a voltage of 10V~100V, the first S1 is turned off.哕坌+ violates the first resistor R1 and the second resistor R2 in parallel, together with the 18th 1279551 - the operational amplifier A1, the fourth resistor R4 and the fifth resistor r5 form a gain value of V汍-ο·〇〇2 The circuit has an inverting amplification effect, and the voltage to be tested is attenuated by 500 times to become the first signal 匕〇. The digital signal processing module 3 sets the third switch s3 and the fifth switch S5 of the amplifying circuit 12 to be off, and turns on the second switch S2, the fourth switch S4 and the sixth switch S6. Send to the second zoom

After the unit 122 is amplified by a factor of 1 and becomes a third signal having a root mean square value of 2 V, the buffer unit 123 outputs the first signal to the first output terminal ac_〇υτ. When S measures the rms voltage at a voltage of 100V to 750V, the first switch si is turned off. Similarly, the first resistor R1, the second resistor R2, the first different polarization state A1, the fourth resistor R4, and the fifth resistor R5 form a circuit with a gain value of -0.002, and the voltage to be tested can be used. The inverse attenuation is 5〇〇 times and becomes the first 佗6 c/. The digital signal processing module 3 sets the fourth switch S4 of the amplifying circuit 丄2 to be turned off, and turns on the second switch S2, the third switch S3, the fifth switch S5 and the sixth switch S6, the first signal 6C7 is sent to the buffer unit 123' and output to the first output terminal ac OUT. It is worth noting that the fourth capacitor C4 in the AC wave circuit 11 is connected across the fourth and fifth resistors R4 and R5, so that a pole frequency is introduced in the AC filter circuit 11. Referring to FIG. 5, the horizontal axis is the voltage frequency of the first input terminal AC-IN, and the vertical axis is the ratio of the first signal and the first input terminal AC-IN voltage, that is, the gain of the AC filter circuit n. value. Before the calibration signal FLATNESS_ADJ is not input to the AC filter circuit ^, since the fourth capacitor C4 introduces a pole having a frequency of about 3 MHz, if the voltage to be tested has an AC voltage corresponding to the pole frequency component, 19 1279551 The AC filter circuit η has a negative value of 交流 for the AC voltage, and the gain value of the other frequency voltages within the bandwidth is negative by 13 979. This is particularly large. The frequency of the signal in FIG. 5 is about 1 Hz. , , ] / / claw power, the gain value is about -16db, which is much smaller than 13.979db. This part of the frequency is only a thousand, and the profit value can be flattened by adjusting the size of the third capacitor C3. In order to avoid the multiple of the AC voltage to be measured at the pole frequency is not attenuated: other frequency voltages within the bandwidth to maintain the cross (four) wave circuit

Seeing the value of the increase in the value of i must be corrected in advance for the dust of the pole frequency. The digital signal processing module 3 stores the voltage value M of the reference signal when the low frequency reference signal within the bandwidth of the field and not equal to the pole frequency is fed by the first input terminal AC_IN. Then, another frequency signal whose peak frequency is exactly the pole frequency and whose rms value is also Μ is sent. Since the voltage gain value of the pole frequency signal is different for the AC filter module i, the digital signal processing module 3 will obtain The measured value of this signal is M, and is more than the difference between the car and the JV. If the error exceeds the allowable range, the digital signal processing module 3 stores the value of Μ_Μ, and sends the pulse width modulation signal PWM proportional to the pulse width to the dragon, to the compensation circuit. The middle, and second compensation circuit 14 filters the pulse width modulation signal PWM into a DC compensation signal whose voltage value is inversely proportional to the pulse width of the pulse width modulation signal PWM, and sends the compensation signal to the addition unit 131. The voltage of the negative 15V and the compensation signal are respectively sent to the adding unit i3i, and the adding unit 131 adjusts the DC voltage level of the compensation signal. The electric dust control variable resistance unit that violates the field effect transistor 20 1279551 132 operates an impedance adjustment signal in a triode region, and the voltage value of the impedance adjustment signal cannot be greater than its pinch voltage (pinch_〇ff v〇hage). The impedance_integrator adjusts the resistance value of the voltage control variable resistance unit 1, and the ninth resistor R9 changes the feedback-back gain of the fifth operational amplifier A5. The correction signal 匕~ is obtained by dividing and filtering the first signal Gc/ corresponding to the pole frequency signal by the sixth resistor R6 and the seventh resistor R7, and feeding the positive phase of the fifth operational amplifier A5. The input terminal is amplified and becomes the calibration signal FLATNESS_ADJ of the positive phase. The calibration signal] pLATNESS-ADJ is sent to the inverting input terminal of the analog amplifier by the second electric valley C2, and the voltage value of the first signal relative to the pole frequency signal can be adjusted, and the digit is associated The measured value of the pole frequency signal received by the signal processing module 3 is close to Μ and reaches an acceptable error range. Since the AC filter circuit 11 has the same pole frequency for each AC voltage measurement range, the flatness adjustment circuit 13 only needs to adjust the different voltage measurement ranges of the pole frequency. In order not to increase the measurement difficulty by sending a reference signal for each measurement, the digital signal processing module 3 can store the error value Μ-Μ corresponding to the AC voltage of different voltage ranges in advance, as long as the selection is performed. Up to the AC voltage measurement range, the error value Μ_Μ prestored in the digital signal processing module 3 can be output via the pulse width modulation signal PWM to compensate the measured value of the AC voltage of the pole frequency Μ', The gain value of the AC voltage in the bandwidth range of the AC filter circuit 11 is maintained to be uniform. Referring to FIG. 6 'the calibration signal FLATNESS_ADJ inputting the AC filter 21 1279551 wave circuit 11 /夂>, after the gain value of the pole frequency, the bandwidth of the AC wave circuit 11 can be 3 〇〇 KHz, and Maintaining the consistency of the gain values in the bandwidth 0, , 'τ, and the above, the first resistor R1, the second resistor R3, the sixth resistor R6, the seventh resistor R7, and the first capacitor through the AC filter circuit 11 of the present invention Ci, the fifth capacitor. The sixth capacitor C6 and the seventh capacitor C7 enable the frequency of the AC voltage to be tested to be attenuated by more than 3 〇db at 8 MHz, so that the AC filter circuit U has a good filtering effect on the AC voltages of all measurement ranges. And the bandwidth is increased to 300 kHz through the fourth capacitor C4. The fourth electric valley C4 introduces a pole frequency in the range of 3 〇〇 KHz of the AC filter circuit u, but the digital signal processing module 3, the compensation circuit 14 and the flatness adjustment can be adopted. The circuit 13 performs gain compensation on the AC voltage corresponding to the pole frequency to maintain the consistency of the gain value of the AC filter circuit u in the 300 kHz bandwidth, and can indeed achieve the object of the present invention. The preferred embodiments of the present invention are not intended to limit the scope of the present invention, and the simple equivalent changes and modifications made in the scope of the invention and the description of the invention are still within the scope of the invention. Inside. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified circuit diagram of a conventional voltage measuring device, illustrating a circuit of an alternating current filtering module; FIG. 2 is a Bode diagram of an alternating current filtering module of the conventional voltage measuring device. It is shown that the bandwidth of the far-passing wave board group is less than 3 oo kHz; 22 1279551 Figure 3 is a block diagram of the voltage measuring device of the present invention; Figure 4 is a detailed circuit diagram of an AC filter and wave module; Figure 5 is an unreceived A Bode diagram of an AC filter module of a calibration signal indicates that the gain value of one pole frequency is large; and FIG. 6 is a Bode diagram of the AC filter module that corrects the gain value after the calibration signal.

twenty three

1279551 [Description of main component symbols] 1 · . ♦ AC filter module 2 · · · AC to DC voltage module 3 · ·. Digital signal processing module 11··· AC filter circuit 12 · ·. Amplifier circuit 121... An amplifying unit 122... A second amplifying unit 123 · · Buffer unit 1 3 · · ♦ Flatness adjusting circuit 1 3 1 ♦ · Adding unit 132 · · Voltage control variable resistance unit 14 · . ♦ Compensation circuit A1 ♦ · First Operational amplifier A2 · · Second operational amplifier A3 · · Third operational amplifier A4 ♦ · Fourth operational amplifier A5 · · Fifth operational amplifier A6 · · Sixth operational amplifier A7 · · Seventh operational amplifier C1 · · First capacitor C2 · · C3 · · C4 · · C5 · · C6 · · C7 · · C8 ·. C9 · * CIO · · CH · · C12 * · C13 · · C14 · · R1 · · R2 * · R3 ·. R4 · · R5 · · R6 · · R7 ·. R8 ♦. R9 · · R10 · · Second capacitor third capacitor fourth capacitor fifth capacitor sixth capacitor seventh capacitor eighth capacitor ninth capacitor tenth capacitor eleventh capacitor Twelfth capacitor thirteenth Receiving a fourteenth resistor capacitance of the first resistance of the second resistor of the fourth resistor third fifth resistor sixth resistor seventh resistor eighth resistor ninth resistor tenth resistor 241,279,551

R11 · ♦ eleventh resistor R12... twelfth resistor R13... thirteenth resistor R14 ·. fourteenth resistor R15 · ♦ fifteenth resistor R16 · · sixteenth resistor R17 · · seventeenth resistor R18 · The eighteenth resistor R19... The nineteenth resistor R20 ·, the twentieth resistor R21 · · The twenty-first resistor R22 · · The twenty-second resistor R23 · The twenty-third resistor R24 · · The twenty-fourth resistor AC —IN first input AC—OUT first output FLATNESS_ADJ calibration signal PWM · pulse width modulation signal VAcr, first signal VAC2· · second signal Vacs′ * third signal vAC4· · correction signal SI first switch S2 —·Second switch S3*... Third switch S4· · · Fourth switch S5, · · Fifth switch S6· ·. Sixth switch

25

Claims (1)

Ϊ 279551 X. Patent application scope: h ~ kind of voltage measuring device, comprising: an AC filter module capable of adjusting flatness, having a first input end and a first output end capable of receiving an AC voltage to be tested, and According to the voltage of the temple, the voltage is appropriately attenuated and outputted through the first output terminal; an AC-to-DC voltage module is electrically connected to the AC filter module, and can receive the voltage An AC voltage of the first output terminal, and converting the AC voltage into a DC voltage having a voltage value equal to an rms value of the AC voltage of the first output terminal; and a digital signal processing module capable of receiving the AC The DC voltage mode is a DC voltage that is rotated, and the DC voltage is converted into a measured value corresponding to the AC voltage to be tested according to the measurement range in which it is located, and a pulse width modulation signal and a control are outputted. Signaling to the AC filter module, the pulse width of the pulse width modulation signal is proportional to the error value of the measured value and the root mean square value of the AC voltage to be measured for the communication The wave module adjusts an output voltage of the first output end, and the control signal can control the edge of the parental flow filter module to be appropriately attenuated after the voltage measurement range is different, and then the first output is The voltage measuring device according to the application scope of the invention, wherein the adjustable flatness AC filter module comprises an AC filter circuit, a flatness trimming circuit, a compensation circuit and an amplification a circuit, the AC filter circuit can receive the AC voltage to be tested, and can attenuate and filter the voltage to be measured into a first signal, and output the signal to the amplifying circuit 26 • 1279551, and output a first The signal obtained by dividing and filtering the signal is sent to the flatness adjusting circuit, so that the flatness adjusting circuit can sample the voltage of the first nickname, and the 戎 amplifying circuit is electrically connected to the alternating current filter circuit, and the A signal is appropriately amplified and output to the first output end, and the compensation circuit can receive the pulse width modulation signal output by the digital signal processing module, and input a compensation signal is inversely proportional to a pulse width of the pulse width modulation signal to the flatness adjustment circuit, the flatness adjustment circuit receives the compensation signal and the correction signal, and outputs a calibration signal to the AC filter circuit The calibration signal can adjust the gain value of the AC filter circuit such that the measured value of the digital signal processing module is equal to the root mean square value of the AC voltage to be tested. 3. According to the scope of the patent application 帛 2 The voltage measuring device of the AC filter module includes a first operational amplifier, a 'first capacitance, a second capacitance, a third capacitance, a fourth capacitance, a fifth capacitance, and a a sixth capacitor, a seventh capacitor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, and a -th switch The first-phase input terminal of the first operation amplification ground is grounded, and the inverting input terminal and the fifth power: the - terminal, the end of the fourth capacitor, one end of the second capacitor, and the "off one end" One of the sixth capacitors The terminal and the second resistor are electrically connected to each other and the output terminal can output the first signal, and: the electric current: the end, the amplifying circuit, the end of the third resistor: the other end of the first One end of the fifth capacitor and the end are electrically connected, and the other end of the mountain is electrically connected to the flatness adjusting circuit 27 1279551 and the end of the f seven resistor, and can be output The correction signal, wherein the other end of the seventh resistor is a ground voltage, the seventh capacitor is connected in parallel with the sixth resistor, and the other end of the fourth capacitor is electrically connected to one end of the third capacitor and one end of the fourth resistor The other end of the third capacitor is electrically connected to the other end of the sixth capacitor, and the other end of the fifth capacitor is connected to the first The other end of the switch, one end of the first capacitor and the other end of the first resistor are electrically connected, and the other end of the second capacitor is electrically connected to the other end of the first capacitor and can receive the calibration signal. The other end of the fourth resistor is electrically connected to the other end of the fifth resistor The first switch control signal is the digital signal processing module receiving the output on or off. 4. The voltage measuring device according to claim 3, wherein when the root mean square value of the AC voltage to be tested is in the range of 〇·1ν, 〇·1ν~ιν, and IV~10V, the digit The control signal outputted by the signal processing module sets the first switch to be turned on; when the square root value of the AC voltage to be tested is in the range of 10V~100V and 100V~750V, the control signal output by the digital 处理 processing module Set the first switch to off. The voltage measuring device according to the second aspect of the patent application, wherein the amplifying circuit of the AC filter module comprises a second switch, a third switch, a fourth switch, a fifth switch, and a sixth a switch, a first amplifying unit, a second amplifying unit and a buffering unit, wherein one end of the second switch is electrically connected to the alternating current filter circuit, and can receive the _th sign and the other end and the first zoom The unit is electrically connected, the first amplifying unit receives the first signal via the second switch, and can transmit the first pass 28 1279551 becomes a second signal after being amplified, and the "terminal" of the fifth switch is electrically connected to the AC chopper circuit, and can receive the first end of the n-th power and the second amplifying unit, the sixth switch The second terminal is electrically connected to the first signal, and the second signal is electrically connected to the first amplifying unit, and the second amplifying unit can receive the first signal via the five switches. And the second signal is received by the sixth switch, and the δ 仏 仏 放大 is amplified to become a third signal, and the fourth terminal is electrically connected to the alternating (four) wave circuit, and can receive the a first signal, and the other end is electrically connected to the buffer unit, the third switch is electrically connected to the second amplifying unit at one end, and can receive the third signal and the other end and the buffer unit are electrically connected. Connected, the buffer unit can receive the first signal by the four switches and can receive the third signal via the third switch, and can output the signals to the first wheel, and the switch is The digital signal processing module outputs the control on or off. 1 6. According to the electric measuring device according to item 5 of the patent application scope, in the basin, when the rms value of the to-be-tested communication is in the range below (4), the control signal output of the digital signal processing module is set. The second opening, the second switch and the sixth switch are set to be off and the fourth switch and the second switch are set to be turned on, and the rms value of the equivalent measurement is in the Q lv~iv<dust dust, = rational module sets the third switch and the fifth switch to off:; rms value in lv~lov power = 2 on; equivalent measurement stalk ^, shou, 5 hai digital signal processing module will be &quot ; four sweat off is set to off, and the second switch, the third switch, 29 1279551 fifth switch and the sixth switch are turned on; the equivalent measurement mean square ... 10V ~ 100V voltage, ^ fw Hai digital signal processing mode The group sets the third switch and the fifth switch to be off' and turns the second switch and the fourth switch to be turned on by six switches; when the equivalent rms value is at a voltage of biliary ~750V, the digital signal processing grip Receive 4 Μ — , , , , and set the fourth switch to off, and The shoulder brother: the switch, the third switch, the fifth switch, and the sixth switch are turned on. The voltage measuring device according to claim 5, wherein the first amplifying unit of the 忒 amplifying circuit comprises a fourteenth resistor, a fifteenth resistor, a sixteenth resistor and a second operational amplifier The end of the fourteenth resistor is electrically connected to the second switch and the non-inverting input terminal of the second operational amplifier, and the other end of the fourteenth resistor is grounded. The tenth, the resistor is connected to the ground voltage. And the inverting input ' of the second operational amplifier, the sixteenth resistor is connected across the inversion of the second operational amplifier, between the input end and the output end, and the output end of the second operational amplifier The sixth switch is electrically connected and outputs the second signal. According to Shen. The voltage measuring device according to item 5 of the patent scope of the present invention, wherein the second amplifying unit of the amplifying circuit comprises a seventeenth resistor y - tenth :) a resistor, a nineteenth resistor and a third operation An amplifier, the third phase π amplification thief of the positive phase input terminal is electrically connected to the fifth switch and the sixth switch, and the seventeenth resistor is connected to the ground potential and the third phase of the third operational amplifier The 18th resistor is connected to the ground potential: between the inverting input terminals of the third operational amplifier, the 19th resistor is connected between the inverting input terminal and the output terminal of the third operational amplifier The output of the third operational amplifier can output the second signal and is electrically connected to the 30 1279551 second switch. 9 · The voltage measuring device according to the 5th Jg, +, and 7+ indications of the patent application scope, wherein the buffering unit of the first amplifying circuit includes a fourth operational amplifier% Ten capacitors, one eleventh capacitor, one Chu—the eleventh resistor and one twentieth lightning resistance, one of the eleventh capacitors 妒 _ ^, the positive phase of the fourth operational amplifier and the first Twenty-six resistors _ Liushanzhong ' * Ding Dian but stand and electrically connected, the eleventh capacitor is another: the end is electrically connected to the fourth switch and the third switch, and the fourth operational amplifier is inverted The input end is electrically connected to the output end and the one end of the 21st, and the other end of the second + 卞窀 卞窀 is the ground voltage, and 5 亥 · 一 ' 一 一 » » » » » » » » » » » » » For the output of the brother, the first capacitor is connected across the second eleventh resistor. τ 10. The measuring device according to the second aspect of the patent, wherein the flatness adjusting circuit of the alternating current filtering module comprises a fifth device, an eighth capacitor, an eighth resistor, a ninth The resistance, the force element and the one electric control can be controlled by the 辔雷 k. The addition unit is electrically connected to the compensation circuit and receives the compensation. The addition method can be adjusted as early as possible. The DC signal of the compensation signal becomes an impedance adjustment signal, and the positive input terminal of the fifth f-counter receives the correction signal, and the inverting input is connected to the female and the thunder of the ninth resistor. * 4 ^ is electrically connected, and the output terminal outputs the calibration nickname 'the eighth capacitor and the eighth resistor are connected across the inverting input terminal and the output terminal of the fifth operational amplifier' (4) After the voltage-controlled variable resistance unit, the mountain + ^ ^ 〃 Μ is electrically connected to one end of the younger brother, the second end of the variable resistance unit is 盥兮, and the —-- Haijia goes to the early electrical connection and receives the impedance adjustment signal, while the second ☆ mountain rabbit eight brothers are the grounding voltage, the voltage control can be the first 矬 31 山 山 山 山The resistance value can be adjusted by changing the voltage of the impedance adjustment signal. η·According to the voltage measurement according to item 10 of the patent application scope,” the addition of the flatness adjustment circuit is abbreviated to a younger brother, an operational amplifier, an electric valley, a tenth resistance, and a Ten-resistor, a tenth-electrical one of the thirteenth resistors, one of the two terminals, the positive-phase input terminal and the other end of the twelve-second resistor are electrically connected, and the /-inverting input terminal and the tenth-resistor One end of the tenth resistor is connected to the end and the output end thereof rotates the impedance adjustment signal, and is electrically connected to the other end, and the other end of the thirteenth resistor is two of the twelfth resistor The other end is coupled to a voltage source, the dipole is connected across the tenth resistor, and the other end of the tenth resistor receives the compensation signal. 12. According to the scope of claim 1 The voltage measurement of the agricultural device, the voltage control variable resistance unit of the flatness adjustment circuit is an N, the field = the field source of the field effect transistor is grounded, and the gate receives the positive phase and the drain Electrically connected to the ninth resistor. U. According to the voltage measuring device described in item 2, The compensation circuit of the AC wave circuit includes a seventh operational amplifier, an eleventh electric valley, a thirteenth capacitance, a fourteenth capacitance, a twenty-second resistance, a twenty-third resistance, and a twenty-fourth resistor, one end of the twelve: twelve resistor is connected to the end of the fourteenth capacitor and the twenty-fourth resistor, and the other end and the end of the twelfth capacitor and the ten The other end of the two resistors is electrically connected, and the other 32 1279551 end of the twenty-fourth resistor receives the pulse width modulation signal, and the other end of the fourteenth capacitor is grounded, and the other end of the tenth capacitor is The inverting input end and the output end of the seventh operational amplifier are electrically connected, and the second-phase resistor is electrically connected to the positive-phase input end and one end of the thirteenth capacitor, and the thirteenth capacitor is electrically connected The other ☆ is the ground voltage. 33