CN103713186A - Motor terminal voltage measuring instrument of alternating current frequency conversion motor - Google Patents

Motor terminal voltage measuring instrument of alternating current frequency conversion motor Download PDF

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Publication number
CN103713186A
CN103713186A CN201310728477.7A CN201310728477A CN103713186A CN 103713186 A CN103713186 A CN 103713186A CN 201310728477 A CN201310728477 A CN 201310728477A CN 103713186 A CN103713186 A CN 103713186A
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China
Prior art keywords
sensor
fpga
measuring instrument
chip
alternating
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CN201310728477.7A
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Chinese (zh)
Inventor
袁新枚
王闯
陈宏羽
刁庆华
纪淑玲
张建
陈浩
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Jilin University
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Jilin University
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Priority to CN201310728477.7A priority Critical patent/CN103713186A/en
Publication of CN103713186A publication Critical patent/CN103713186A/en
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Abstract

The invention discloses a motor terminal voltage measuring instrument of an alternating current frequency conversation motor, and aims to solve the problems that if errors of motor terminal voltages which are acquired by converting collected direct current bus voltages are large or if the motor terminal voltages are directly measured, due to the characteristics of PWM square waves, high digital sampling frequency and high-speed digital signal processing are needed, and an ordinary controller can not meet the requirements. The measuring instrument (5) comprises a sensor, a sampling resistor, an AD sampling module and an FPGA. The input end of the sensor is electrically connected with the output end of an inverter (2), the output end of the sensor is electrically connected with one end of the sampling resistor, the other end of the sampling resistor is electrically connected with the signal input end of the AD sampling module, and the signal output end of the AD sampling module is connected with the input end of the FPGA through an I/O port. The input port of the measuring instrument is electrically connected with the output end of the inverter (2) through the sensor, and the output port of the measuring instrument is electrically connected with the input end of a motor controller (4) through the FPGA (field programmable gate array).

Description

The set end voltage measuring instrument of alternating-current variable frequency motor
Technical field
The present invention relates to a kind of measuring mechanism, or rather, the present invention relates to a kind of set end voltage measuring instrument of alternating-current variable frequency motor.
Background technology
Along with the develop rapidly of Power Electronic Technique, alternating-current variable frequency motor is widely applied in industry member.In alternating-current variable frequency motor system, control algolithm is the core of decision systems performance, and the accuracy of sensor collection signal will directly have influence on the effect of control algolithm.Due to the terminal voltage of the alternating-current variable frequency motor PWM form that is high-frequency and high-voltage, cannot realize at present sensor measures in real time, so industry member is generally used voltage sensor to measure inverter input terminal voltage (as shown in Vdc in Fig. 1) replacement motor terminal voltage (as shown in Vac in Fig. 1) at present.Due to the accurate loss of voltage of taking into account inverter of this measuring method, so the voltage error of measuring is larger, how accurately obtains motor terminal voltage and be subject in recent years extensive concern both domestic and external.
The measuring accuracy of alternating-current variable frequency power set end voltage not only affects Electric Machine Control performance, and the development important in inhibiting to electric machine without position sensor technology.So-called electric machine without position sensor technology is exactly to utilize the voltage of motor, current information to estimate a kind of method of motor rotor position information.In the not high application scenario of reliability requirement, utilize the position-sensor-free technology can be cost-saving, the work of save purchase, rotor-position sensor being installed; In the higher occasion of reliability requirement, position-sensor-free technology can be used as the backup of position transducer, the in the situation that of the sensor failure of position, system is normally worked.Obviously, the precision that motor terminal voltage is measured will have influence on the precision that rotor-position is estimated, in fact, cannot obtain terminal voltage accurately affects the key factor that position-sensor-free technology at present cannot spread just.
By literature search and investigation, terminal voltage measuring accuracy is also just by foreign scholar, to be paid attention in nearly 5 years on the impact of position-sensor-free technical feature, at present both at home and abroad all without the method for direct Measurement accuracy alternating-current variable frequency motor machine end PWM voltage.
Summary of the invention
If technical matters to be solved by this invention is to have overcome the collection DC bus-bar voltage that prior art exists, the terminal voltage that conversion obtains is the pressure drop of taking into account inverter accurately, if error is measured greatly and directly motor terminal voltage, characteristic due to PWM square wave, need high digital sample frequency and digital signal processing at a high speed, the problem that Common Controller cannot be realized, provides a kind of set end voltage measuring instrument of alternating-current variable frequency motor.
For solving the problems of the technologies described above, the present invention adopts following technical scheme to realize: the set end voltage measuring instrument of described alternating-current variable frequency motor includes sensor, sampling resistor, AD sampling module and FPGA.
The input end of sensor is connected with the output terminal electric wire of inverter, the output terminal of sensor is connected with an end cable of sampling resistor, the other end of sampling resistor is connected with the signal input part electric wire of AD sampling module, and the signal output part of AD sampling module is connected by I/O mouth with FPGA input end.
Sensor described in technical scheme is selected the sensor of HV-C04 series, and it is 0201 Chip-R that sampling resistor is selected model, and it is the ADC chip of AD574A that AD sampling module is selected model, and FPGA is field programmable gate array; One end electric wire of the Chip-R that the output terminal Vc of HV-C04 series sensor is 0201 with model is connected, model is that the Vi pin electric wire of the other end of 0201 the Chip-R ADC chip that is AD574A with model is connected, and the R mouth of the ADC chip that model is AD574A is connected with the IN mouth electric wire of D mouth and FPGA; Model is that 0201 Chip-R, ADC chip and the FPGA that model is AD574A are welded on same circuit board.
Sensor described in technical scheme is selected the sensor of LV25-P series, and it is 0402 Chip-R that sampling resistor is selected model, and it is the ADC chip of ADC0809 that AD sampling module is selected model, and FPGA is field programmable gate array; One end electric wire of the Chip-R that the output terminal OUT of LV25-P series sensor is 0402 with model is connected, model is that the IN0 pin of the other end of 0402 the Chip-R ADC chip that is ADC0809 with model is connected with IN1 pin electric wire, and the D0 mouth of the ADC chip that model is ADC0809 is connected with the IN mouth electric wire of D1 mouth and FPGA; Model is that 0402 Chip-R, ADC chip and the FPGA that model is ADC0809 are welded on same circuit board.
The input port of the set end voltage measuring instrument of the alternating-current variable frequency motor described in technical scheme is connected with inverter output end electric wire by sensor, and the delivery outlet of the set end voltage measuring instrument of alternating-current variable frequency motor is that field programmable gate array is connected with electric wire with the input end of electric machine controller by FPGA.
Compared with prior art the invention has the beneficial effects as follows:
1. consult Fig. 1, due to the terminal voltage of the alternating-current variable frequency motor PWM form that is high-frequency and high-voltage, cannot realize at present sensor and measure in real time, so industry member is generally used voltage sensor to measure inverter input direct-current bus terminal voltage Vdc replacement alternating-current variable frequency power set end voltage Vac at present.Consult Fig. 2, if measure the DC bus-bar voltage of inverter input terminal, the accurately pressure drop of taking into account inverter of alternating-current variable frequency power set end voltage that converts and obtain, error is larger.Consult Fig. 3, the present invention has improved existing scheme, output terminal at inverter has increased the high-speed AD sampled voltage measuring instrument based on FPGA, can accurately measure like this inverter output end voltage (being alternating-current variable frequency power set end voltage), avoid the measuring voltage error causing due to inverter pressure drop, thereby improve the control performance of motor.
2. the terminal voltage of alternating-current variable frequency motor is except having conclusive impact the control performance of alternating-current variable frequency motor, some application technologies to alternating-current variable frequency motor also have a significant impact, for example in position-sensor-free, utilize alternating-current variable frequency power set end voltage to determine rotor-position, and the precision that the Accuracy that alternating-current variable frequency power set end voltage is measured is estimated to rotor-position, this is the key factor that position-sensor-free technology at present cannot spread, the method of the measurement motor terminal voltage that the present invention proposes has obtained terminal voltage accurately, be conducive to the popularization of position-sensor-free technology.
3. the PWM form that is high-frequency and high-voltage due to the terminal voltage of alternating-current variable frequency motor, general frequency is about 5-20KHz, and the characteristic that determines this signal amplitude is the ratio of shared time of high level pulsewidth in the square-wave signal one-period of high frequency for this reason.
As: alternating-current variable frequency motor voltage pwm frequency is 10kHz, be to be 100us in the PWM cycle, if voltage sample frequency is up to 1MHz, its measuring accuracy time precision is 1us, visible its measuring error is up to 1%, and high like this sample frequency will take the resource of a large amount of single-chip microcomputers, practical application is very difficult.
And the high-speed AD sampled voltage measuring instrument based on FPGA of the present invention, adopt high-speed ADC chip, a passage has the sampling rate of 1Gb/s, if on a slice ADC integrated two-way independently ADC there is 8bit conversion accuracy, each passage has the sampling rate of 1Gb/s, and under interleaving mode, two-way ADC parallel sampling can reach the sampling rate of 2Gb/s.Select the ADC of inner integrated output buffer simultaneously, can reduce and data transfer rate, be conveniently directly connected with polytype high speed FPGA, realize high data rate Storage and Processing.Utilize FPGA directly to control ADC chip signal is sampled, then the data of having changed are stored into rapidly in the storer of FPGA inside, data acquisition and data transmit and are independent of single-chip microcomputer, have reduced the requirement to single-chip microcomputer frequency.FPGA software processing capacity is powerful, except utilizing it, control ADC chip and storage data, can also carry out to the data that collect calculating, the FFT(Fast Fourier Transform (FFT) of actual duty cycle), the aspect such as filtering processes, and meets the Electric Machine Control algorithm requirements of all kinds of complexity.
Therefore, the present invention is in the situation that realizing voltage high speed sampling, the required sample frequency of alternating-current variable frequency motor control system will significantly be reduced, broken away from the classic method that adopts the microprocessors such as DSP, single-chip microcomputer to be configured, realized the independent acquisition and processing to alternating-current variable frequency power set end voltage data, to high-performance AC variable-frequency motor, controlled significant.
Accompanying drawing explanation
Below in conjunction with accompanying drawing, the present invention is further illustrated:
Fig. 1 is that alternating-current variable frequency motor control system structure forms schematic block diagram;
Fig. 2 is that in conventional art, alternating-current variable frequency motor control system structure forms schematic block diagram;
Fig. 3 adopts the alternating-current variable frequency motor control system structure of the set end voltage measuring instrument of alternating-current variable frequency motor of the present invention to form schematic block diagram;
Fig. 4 is the structural principle schematic block diagram of the set end voltage measuring instrument of alternating-current variable frequency motor of the present invention;
In figure: 1. direct supply, 2. inverter, 3. alternating-current variable frequency motor, 4. electric machine controller, 5. the set end voltage measuring instrument of alternating-current variable frequency motor.
Embodiment
Below in conjunction with accompanying drawing, the present invention is explained in detail:
Consulting Fig. 2, is traditional alternating-current variable frequency motor control system shown in figure, comprises direct supply 1, inverter 2, alternating-current variable frequency motor 3 and electric machine controller 4.Direct supply 1 output terminal is connected with the input end of inverter 2 by DC bus, and the output terminal of inverter 2 is connected with motor 3 by three-phase power line;
Traditional alternating-current variable frequency motor control system is to measure the DC voltage value Vdc of inverter 2, utilizes this magnitude of voltage Vdc to calculate the terminal voltage value Vac of alternating-current variable frequency motor 3 as the voltage feedback signal of electric machine controller 4.The terminal voltage value Vac of the motor 3 that this classic method calculates is the nonlinear effect of taking into account inverter 2 accurately, thereby causes the motor terminal voltage value Vac error of feedback relatively large, is unfavorable for the control of high-performance motor.
Consulting Fig. 3, is the alternating-current variable frequency motor control system that application pressure measuring instrument provided by the invention gathers alternating-current variable frequency motor 3 terminal voltages in figure.Applying the alternating-current variable frequency motor control system of pressure measuring instrument provided by the present invention compares with traditional alternating-current variable frequency motor control system recited above, input to the terminal voltage value Vac source difference of the alternating-current variable frequency motor 3 of electric machine controller 4, the latter adopts output end voltage (being alternating-current variable frequency power set end voltage) value Vac that a kind of high-precision pressure measuring instrument 5 measures inverter 2 as the voltage signal that inputs to electric machine controller 4, the output end voltage of the measurement inverter 2 measuring is like this required alternating-current variable frequency power set end voltage values, eliminated the pressure drop error of inverter 2.
Consult Fig. 4, the set end voltage measuring instrument 5 of alternating-current variable frequency motor provided by the present invention is to comprise sensor, sampling resistor, AD sampling module, FPGA(field programmable gate array).
The effect of sensor changes into low tension signal by inverter 2 output high-voltage signals, and low tension signal could be used by AD sampling module.While selecting sensor, mainly consider tested voltage range, output signal.
AD sampling module is a high speed voltage sampling module, realizes the collection to the PWM ripple of high-frequency and high-voltage.The high-speed ADC chip adopting, a passage need to have sampling rate more than 1Gb/s, if on a slice ADC integrated two-way independently ADC there is 8bit conversion accuracy, each passage has the sampling rate of 1Gb/s, under interleaving mode, two-way ADC parallel sampling need to reach sampling rate more than 2Gb/s.Select the ADC of inner integrated output buffer simultaneously, can reduce output data rate like this, conveniently with polytype high speed FPGA(field programmable gate array) be directly connected.
FPGA(field programmable gate array) effect is to utilize it to control ADC chip and storage data, can also carry out to the data that collect calculating, the FFT(Fast Fourier Transform (FFT) of actual duty cycle simultaneously), the aspect such as filtering processes.FPGA(field programmable gate array) software processing capacity is powerful, can realize the data that AD module is collected and processes fast and store.The output of AD module and FPGA(field programmable gate array) input be all designed to LVDS(universal interface standard) logical criteria, can realize AD module and FPGA(field programmable gate array) seamless link.
The input end of sensor is used electric wire to be connected with the output terminal of inverter, the output terminal of sensor is used electric wire to be connected with one end of sampling resistor, the other end of sampling resistor is connected with the signal input port electric wire of AD module, AD module and FPGA(field programmable gate array) by I/O mouth, be connected, sampling resistor, ADC chip, FPGA are welded on same circuit board.
Embodiment one, the output terminal Vc of HV-C04 series sensor is used electric wire to connect sampling resistor (Chip-R that model is 0201) one end, the Vi pin of the ADC chip that the model of another termination U.S. AD company of sampling resistor (Chip-R that model is 0201) is AD574A, model is on the R and IN mouth that D mouth meets FPGA of ADC chip of AD574A, sampling resistor (Chip-R that model is 0201) wherein, model is the ADC chip of AD574A, FPGA is welded on same circuit board, the delivery outlet of pressure measuring instrument is connected with signal wire with the input end that connects electric machine controller 4.
Embodiment two, the output terminal OUT of LV25-P series sensor is used electric wire to connect one end of sampling resistor (Chip-R that model is 0402), IN0 and the IN1 pin of the ADC chip that another termination model of sampling resistor (Chip-R that model is 0402) is ADC0809, model is that D0 mouth and the D1 mouth of the ADC chip of ADC0809 connects FPGA(field programmable gate array) IN mouth on, sampling resistor (Chip-R that model is 0402) wherein, model is the ADC chip of ADC0809, FPGA is welded on same circuit board, the delivery outlet of pressure measuring instrument is connected with signal wire with the input end that connects electric machine controller 4.
Use the principle of work of alternating-current variable frequency motor control system of the set end voltage measuring instrument of alternating-current variable frequency motor of the present invention:
Direct supply 1 by DC bus by direct voltage output to inverter 2, the DC voltage of 2 pairs of inputs of inverter is changed, the three-phase square wave PWM voltage that is converted to is for alternating-current variable frequency motor 3 work.
Electric machine controller 4 gathers the terminal voltage value Vac of the alternating-current variable frequency motor 3 that the set end voltage measuring instrument 5 of alternating-current variable frequency motors measures for the control (compare and regulate the output voltage values of inverter 2 or carry out the work such as position-sensor-free rotor-position estimation with demand voltage) of alternating-current variable frequency motor 3, thereby makes alternating-current variable frequency motor 3 reach demand duty.
The principle of work of the set end voltage measuring instrument of alternating-current variable frequency motor of the present invention:
Inverter 2 output voltages are converted into low tension signal by the sensor in the set end voltage measuring instrument 5 of alternating-current variable frequency motor, then utilize FPGA(field programmable gate array) control the collection of ADC chip high speed by the sensor signal of sampling resistor, data after the sampling of ADC chip are passed to FPGA(field programmable gate array), FPGA(field programmable gate array) data that collect being done to signal processes, be sample phase and data fetch phase, sample phase FPGA(field programmable gate array) controlling ADC chip samples to signal, then store rapidly the data of having changed into FPGA(field programmable gate array) in inner storer, data fetch phase, FPGA(field programmable gate array) call high-speed sampling data in storer and high-speed sampling data carried out to required signal and process (as: dutycycle is calculated, FFT(Fast Fourier Transform (FFT)), filtering etc.), relevant treatment result store is at FPGA(field programmable gate array) storer in power supply machine controller take.FPGA(field programmable gate array) to the data that collect and after processing, data are passed to electric machine controller 4, electric machine controller 4 utilizes this value to carry out the control of alternating-current variable frequency motor.

Claims (4)

1. a set end voltage measuring instrument for alternating-current variable frequency motor, is characterized in that, the set end voltage measuring instrument (5) of described alternating-current variable frequency motor includes sensor, sampling resistor, AD sampling module and FPGA;
The input end of sensor is connected with the output terminal electric wire of inverter (2), the output terminal of sensor is connected with an end cable of sampling resistor, the other end of sampling resistor is connected with the signal input part electric wire of AD sampling module, and the signal output part of AD sampling module is connected by I/O mouth with FPGA input end.
2. according to the set end voltage measuring instrument of alternating-current variable frequency motor claimed in claim 1, it is characterized in that, described sensor is selected the sensor of HV-C04 series, it is 0201 Chip-R that sampling resistor is selected model, it is the ADC chip of AD574A that AD sampling module is selected model, and FPGA is field programmable gate array;
One end electric wire of the Chip-R that the output terminal Vc of HV-C04 series sensor is 0201 with model is connected, model is that the Vi pin electric wire of the other end of 0201 the Chip-R ADC chip that is AD574A with model is connected, and the R mouth of the ADC chip that model is AD574A is connected with the IN mouth electric wire of D mouth and FPGA; Model is that 0201 Chip-R, ADC chip and the FPGA that model is AD574A are welded on same circuit board.
3. according to the set end voltage measuring instrument of alternating-current variable frequency motor claimed in claim 1, it is characterized in that, described sensor is selected the sensor of LV25-P series, it is 0402 Chip-R that sampling resistor is selected model, it is the ADC chip of ADC0809 that AD sampling module is selected model, and FPGA is field programmable gate array;
One end electric wire of the Chip-R that the output terminal OUT of LV25-P series sensor is 0402 with model is connected, model is that the IN0 pin of the other end of 0402 the Chip-R ADC chip that is ADC0809 with model is connected with IN1 pin electric wire, and the D0 mouth of the ADC chip that model is ADC0809 is connected with the IN mouth electric wire of D1 mouth and FPGA; Model is that 0402 Chip-R, ADC chip and the FPGA that model is ADC0809 are welded on same circuit board.
4. according to the set end voltage measuring instrument of alternating-current variable frequency motor claimed in claim 1, it is characterized in that, the input port of the set end voltage measuring instrument of described alternating-current variable frequency motor is connected with inverter (2) output terminal electric wire by sensor, and the delivery outlet of the set end voltage measuring instrument of alternating-current variable frequency motor is that field programmable gate array is connected with electric wire with the input end of electric machine controller (4) by FPGA.
CN201310728477.7A 2013-12-25 2013-12-25 Motor terminal voltage measuring instrument of alternating current frequency conversion motor Pending CN103713186A (en)

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Application publication date: 20140409