CN113644855A - High-frequency converter - Google Patents
High-frequency converter Download PDFInfo
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- CN113644855A CN113644855A CN202110812309.0A CN202110812309A CN113644855A CN 113644855 A CN113644855 A CN 113644855A CN 202110812309 A CN202110812309 A CN 202110812309A CN 113644855 A CN113644855 A CN 113644855A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/22—Current control, e.g. using a current control loop
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/0003—Control strategies in general, e.g. linear type, e.g. P, PI, PID, using robust control
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/05—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation specially adapted for damping motor oscillations, e.g. for reducing hunting
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/14—Estimation or adaptation of machine parameters, e.g. flux, current or voltage
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/14—Estimation or adaptation of machine parameters, e.g. flux, current or voltage
- H02P21/18—Estimation of position or speed
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/24—Vector control not involving the use of rotor position or rotor speed sensors
- H02P21/28—Stator flux based control
- H02P21/30—Direct torque control [DTC] or field acceleration method [FAM]
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
- H02P25/02—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the kind of motor
- H02P25/022—Synchronous motors
- H02P25/024—Synchronous motors controlled by supply frequency
- H02P25/026—Synchronous motors controlled by supply frequency thereby detecting the rotor position
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
- H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
- H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using DC to AC converters or inverters
- H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using DC to AC converters or inverters with pulse width modulation
- H02P27/085—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using DC to AC converters or inverters with pulse width modulation wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency
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- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
- H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
- H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using DC to AC converters or inverters
- H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using DC to AC converters or inverters with pulse width modulation
- H02P27/12—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using DC to AC converters or inverters with pulse width modulation pulsing by guiding the flux vector, current vector or voltage vector on a circle or a closed curve, e.g. for direct torque control
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- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/14—Electronic commutators
- H02P6/16—Circuit arrangements for detecting position
- H02P6/18—Circuit arrangements for detecting position without separate position detecting elements
- H02P6/182—Circuit arrangements for detecting position without separate position detecting elements using back-emf in windings
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/20—Modifications to facilitate cooling, ventilating, or heating
- H05K7/2089—Modifications to facilitate cooling, ventilating, or heating for power electronics, e.g. for inverters for controlling motor
- H05K7/20909—Forced ventilation, e.g. on heat dissipaters coupled to components
- H05K7/20918—Forced ventilation, e.g. on heat dissipaters coupled to components the components being isolated from air flow, e.g. hollow heat sinks, wind tunnels or funnels
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P2207/00—Indexing scheme relating to controlling arrangements characterised by the type of motor
- H02P2207/05—Synchronous machines, e.g. with permanent magnets or DC excitation
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Microelectronics & Electronic Packaging (AREA)
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- Control Of Ac Motors In General (AREA)
Abstract
The invention discloses a high-frequency converter, which is applied to high-performance application occasions of permanent magnet motors with high speed, high precision or high reliability, such as a high-speed grinding machine, a fuel cell compressor, PCB drilling, an automobile main drive and the like; the control target is high speed, high precision, low loss and low vibration; the type of the motor which can be driven is a three-phase direct current brushless, permanent magnet synchronous and alternating current asynchronous motor, a magnetic field directional control algorithm is adopted, and the position, speed or torque control can be realized by using PG; the invention has the advantages that the position sensor is not needed, the PG is not needed, the speed control can be realized, and the invention has originality; obvious advantages and wide application.
Description
Technical Field
The invention relates to a high-frequency converter.
Background
The high-frequency converter and the main shaft are core functional components of equipment such as a medium-high-end numerical control grinding machine, a compressor, a fan, PCB (printed circuit board) drilling, a molecular pump and the like, a motor/main shaft driving system with high rotating speed, high efficiency, high reliability and low vibration is one of key technologies for ensuring performance indexes such as the processing precision, the efficiency, the service life and the like of the equipment, the output frequency of the frequency converter on the market is generally lower than 600Hz at present (the high-frequency converter of the invention is a frequency converter with the output frequency higher than 600 Hz), the rotating speed of a corresponding pair of motor/main shaft is below 3.6 thousands of revolutions per minute, if higher rotating speed is required, the high-frequency converter and the main shaft driving system can be realized only by adding a speed increasing box in the traditional mechanical transmission link, and the defects of high machine purchasing cost, high operating cost, high maintenance cost, large volume and the like exist.
In order to realize high-performance control of high rotating speed, high efficiency, high reliability, low vibration and the like of a motor/main shaft, a high-performance vector frequency converter is required to be adopted by a matched driving system in the existing scheme, namely a mechanical position sensor is used for collecting rotor position and rotating speed data, and a high-performance MCU (microprogrammed control unit) realizes the implementation of a magnetic Field Oriented Control (FOC) algorithm, but the defects of increased system complexity, reduced reliability, high-speed fault rate, high use cost and the like caused by the installation of the position sensor are overcome, on the basis of the existing inductive control, a non-inductive control algorithm is added for the high-speed running occasion (more than 600 Hz) of the motor, and the basic principle is as follows: the permanent magnet motor is regarded as a sensor, three-phase input voltage of the motor is regarded as excitation of the sensor, three-phase feedback current of the motor is regarded as response of the sensor, the position of a rotor is accurately calculated on line through an algorithm to realize magnetic field directional control, high-precision control of the speed of the permanent magnet motor is realized under the condition of not using a mechanical position sensor, the production, assembly and use costs of the motor are greatly reduced, and meanwhile, the popularization technical threshold of the permanent magnet motor is reduced.
In a motor driving system, the frequency of a PWM carrier of a frequency converter must be higher than 30 times of its output frequency, otherwise the output frequency rises sharply due to the rise of the indicators such as motor vibration, efficiency, heat generation, etc., the operation speed of an MCU in FOC control must be kept synchronous with the frequency of the PWM carrier, i.e., the MCU must complete an SVC algorithm once in a PWM period, for example, the frequency converter outputs 2500Hz, the frequency of the PWM carrier is 80kHz, the corresponding time interval is 1.25us, the SVC algorithm needs more than 30us to operate once according to the operation capability of a general MCU in the existing market, and cannot meet the requirement of a high-frequency driver on the operation capability of a controller, which is one of the important reasons that the output frequency of a general frequency converter driver in the existing market is limited to below 500-600 Hz.
Disclosure of Invention
The invention aims to provide a high-frequency converter which is easy to implement and can obviously improve the rotating speed of a motor.
The technical solution of the invention is as follows:
a high-frequency converter comprises a controller, a signal acquisition circuit and a high-frequency inverter bridge; the signal acquisition circuit is connected with the controller; the controller is connected with the high-frequency inverter bridge through the isolation circuit;
the controller is provided with a core module; the core module comprises an MCU minimum system and a peripheral circuit; the method can be realized by an IP core or a GPU; the controller is also provided with a soft core control module; the soft core control module comprises a finite state machine FSM, an ADC synchronous acquisition unit (ADC interface), a Clarke conversion unit, a Park conversion unit, a back electromotive force observer (ABobsrv), a speed filter (GetVel), a speed ring controller (vPi), a current ring controller (dPi/qPi), a Park inverse conversion unit (invPark), a Clarke inverse conversion unit (invClarke) and a central symmetry vector PWM modulator (SVM); the controller sends out driving pulses through the centrosymmetric vector PWM modulator to drive the inverter to work.
Finite state machine FSM: in a control period, the FSM core firstly controls the ADC synchronous acquisition unit to acquire feedback data required by the SVC algorithm, then controls the SVC algorithm peripheral to execute the SVC algorithm in a chip according to the sequence from top to bottom, and finally outputs control pulses to control a high-frequency inverter bridge outside the chip, and the next period repeats the steps; the analog quantity acquired by the ADC synchronous acquisition unit comprises: three-phase current ia/b/cBus voltage VDCMotor temperature TempMOTORTemperature Temp of base of frequency converterVFDInputting 0-10V/4-20mA of analog quantity of a host computer; the analog quantity input of the upper computer is 0-10V/4-20mA for receiving a control signal of the upper computer (an industrial personal computer, a PLC and the like);
the Clarke transformation unit is used for executing amplitude equivalent Clarke transformation to obtain iα、iβ
Clarke transform, the positive transform being current and the negative transform being voltage; wherein:
iA、iBand ICThree-phase currents, currents in three-phase coordinates, i.e. corresponding to ia/b/c;iα、iβIs two-phase current of an alpha-beta coordinate system of the motor; the Park conversion unit is used for converting the rotor position theta according to the previous control periodrPerforming coordinate axis rotation operation to obtain AC and DC axis current components iq、id;
A back electromotive force observer (ABobsrv) for obtaining a back electromotive force;
whereinIs the output of the counter electromotive force observer; g (z) is a digital model of the single-phase winding of the motor, the input quantity of the digital model is the difference between the input phase voltage and the back electromotive force of the motor, and the output quantity is the phase current:
l, R are respectively the inductance and resistance of the motor stator phase winding, and Tp is the SVPWM period; d (z) observer controller:Kp=2ξω0L-R,KI=ω0LTsξ、ω0respectively the damping ratio and the undamped oscillation frequency of the counter electromotive force observer; e (z) z transformation for counter electromotive force; kp and KI are proportional coefficient and integral coefficient Kp, KI is prior art, and the numerical value is configured according to the winding parameter of the motor
The velocity filter (GetVel) is used to obtain the velocity d θ (n) of the nth sampling point, and the calculation formula is: to;
d θ (n) ═ θ (n) - θ (n-1), θ (n) and θ (n-1) are the rotor positions at the times n and n-1, respectively; a speed loop controller (vPi), in the vPi speed loop, the given value Ref is a speed command, the feedback value Fb is a feedback speed, and the output Out is a q-axis command current iq;iqThe amplitude limit of (a) depends on the rated current of the motor; current loop controller (dPi/qPi): dPi the current loop controller has given value Ref of 0 and feedback value Fb of feedback current idThe output is Vd(ii) a qPi Current Loop controller, given value Ref being speed Loop output iqThe feedback value Fb is the feedback current iqThe output is Vq(ii) a Two current loop controlThe amplitudes of the output Vd, Vq must satisfy:
vPi, dPi, qPi are identical IP cores, and the functions to be realized are: a Pi controller resistant to integral saturation;
the Park inverse transformation unit (invPark) is used for Park inverse transformation, namely d-q axis is transformed to alpha-beta axis; the Park inverse transformation is the prior art, and the specific formula isV to be output by dPi, qPi controllersd、vqTransforming from the rotor coordinate system to the stator coordinate system;
performing clarke inverse transformation (invClarke) on the clarke inverse transformation, and equivalently converting the alpha-beta axis voltage vector into an a-b-c three-phase coordinate system;vdc is the dc bus voltage and Tp is the SVPWM period.
Central symmetric vector PWM modulators (SVMs) are prior art, see the link:
https://wenku.baidu.com/view/9b51ae394531b90d6c85ec3a87c24028915f85 22.htmlSVPWM is a well established technology.
The calculation logic: the process of generating va, vb, vc according to the output result vd, vq of the controller is
The high-frequency converter also comprises a Modbus-RTU protocol IP core for controlling the high-speed bus, and the Modbus-RTU protocol IP core is in butt joint with a touch display screen, a PC (personal computer) or a PLC (programmable logic controller).
The high-frequency converter further comprises a permanent magnet motor SVC IP core, and the permanent magnet motor non-inductive vector control (SVC) is used for determining the position of the rotor of the permanent magnet motor without a position sensor.
The controller is communicated with the upper computer through a serial port. The UART1 interface, such as a controller, communicates with the PC via the RS232 protocol.
A drive control method of a high-frequency converter is based on the high-frequency converter; the control method is a non-inductive vector control method;
soc (System on chip) based on FPGA is designed to be used as the main Control of the high-frequency converter, and FOC-Field Oriented Control (FOC-Field Oriented Control, also called Vector Control) and SVC (sensory Vector Control) algorithms of a motor Control algorithm are all realized by adopting an IP soft core.
The processes of starting, running, stopping, adaptive parameter adjustment and the like of the motor running are independently completed by the soft core control modules, a bus is not occupied, no interruption is caused, and the technical route can enable an Soc system to process an SVC algorithm at the speed of 120kHz at most in real time.
Has the advantages that:
the invention provides a high-frequency converter, which is applied to high-performance application occasions of permanent magnet motors with high speed, high precision or high reliability, such as a high-speed grinding machine, a fuel cell compressor, PCB drilling, an automobile main drive and the like; the control target is high speed, high precision, low loss and low vibration; experimental results can verify that the high-frequency converter can realize high speed, high precision, low loss and low vibration, the type of the drivable motor is a three-phase direct current brushless, permanent magnet synchronous and alternating current asynchronous motor, a magnetic field directional control algorithm is adopted, and the position, speed or torque control can be realized by using PG (PG); and the speed control can be realized without a position sensor and PG.
The core of the invention is to design a high-speed controller based on IP soft core
The invention provides a product structure design method with isolation, heat dissipation, shielding and integrated molding.
The high-frequency converter can be used for a three-phase permanent magnet synchronous motor, a direct current brushless motor and an alternating current asynchronous motor, and adopts an FOC algorithm.
The high-frequency converter adopts non-inductive vector control, a permanent magnet motor is regarded as a sensor, the input voltage of the motor is regarded as the excitation of the sensor, the feedback current of the motor is regarded as the response of the sensor, the position of a rotor is accurately calculated on line through a calculation method so as to realize the directional control of a magnetic field, and the high-precision control of the speed of the permanent magnet motor is realized under the condition of not using a mechanical position sensor.
The high-frequency converter adopts Soc (System on chip) based on FPGA as the main control of the high-frequency converter, and the FOC algorithm of the motor control algorithm and the present SVC (sensory Vector control) algorithm are realized by adopting an IP soft core.
The invention provides a high-frequency direct-drive scheme, the highest output frequencies of a frequency converter driving a permanent magnet motor and an asynchronous motor can reach 2500Hz and 8000kHz respectively, and the rotating speeds of corresponding pair of motors are 15 ten thousand and 48 ten thousand revolutions per minute respectively.
The invention develops a complete SVC (sensory Vector control) algorithm based on HDL (hardware description language), a hardware platform is based on a super large scale integrated circuit, each functional unit of a control flow is instantiated into an independent chip by adopting a modular design method, and the SVC algorithm control is realized by using an IP soft core, so that the bottleneck problem of the operational capability of an MCU (microprogrammed control unit) is solved.
Drawings
FIG. 1 is a block diagram of the overall structure of a high frequency converter;
FIG. 2(a) is a schematic diagram of the analog quantity control of the high frequency converter;
FIG. 2(b) is a schematic diagram of digital control of the high frequency converter;
FIG. 2(c) is a schematic diagram of bus control of the high frequency converter;
FIG. 2(d) a schematic diagram of servo control of the high frequency converter;
FIG. 3 is a Soc-based high frequency converter system configuration;
FIG. 4 is a timing diagram of a centrosymmetric vector PWM;
FIG. 5 is a block diagram of an anti-integral saturation PI controller;
FIG. 6 is a stator single phase winding circuit;
FIG. 7 is a signal flow diagram of a stator single-phase winding;
FIG. 8 is a counter electromotive force viewer;
FIG. 9 is an equivalent flow chart of back EMF detection;
FIG. 10 is a block diagram of a high frequency converter universal main control board system;
FIG. 11 is a block diagram of a high frequency driving board;
FIG. 12 is a three-phase current measured waveform;
FIG. 13 is a waveform of a command pulse width measurement;
FIG. 14 is a three-phase voltage waveform;
FIG. 15 shows the input and output synchronous waveforms of the alpha axis of the counter electromotive force observer;
FIG. 16 shows the back EMF and phase detection results in an α - β coordinate system;
FIG. 17 is an α -axis counter electromotive force and current waveform;
FIG. 18 is a waveform diagram of the input and output of the speed controller during the acceleration phase;
FIG. 19 is a graph of control accuracy and speed controller output for high speed steady state operation;
fig. 20 is a torque waveform display at the acceleration/deceleration stage of the high frequency inverter.
Variables in the figures and in the text of the description:
u (t): motor phase voltage; u(s), U (z): laplace transform and z transform of phase voltages;
i (t): motor phase current; s, z: laplacian, z-transform operator; i(s), I (z): laplace transform, z-transform of phase currents; e (t): the motor counter electromotive force; e(s),E (z): laplace transform and z transform of the opposite electromotive force; l, R: equivalent inductance and resistance of the motor stator; g (z): phase voltage and opposite electromotive force are input, phase current is output, and the ideal digital model of the single-phase winding is obtained;a G (z) approximation to the idealized model; t isp: a PWM carrier period; t isu/v/w: the pulse width of the u, v and w phase PWM commands; t isDB: PWM dead time; u shapeT、VT、WT: u, v, w phase inversion bridge upper arm switch signal, controller chip pin; u shapeB、VB、WB: u, v and w phase inversion bridge lower arm switching signals and a controller chip pin; FOC: field Oriented Control; SVC: sensorless Vector control (Sensorless Vector control); z: a digital system delay algorithm; kp: a controller ratio parameter; ki: a controller integration parameter; kc: a controller anti-saturation factor; ref: a controller command reference value; fb: the controller inputs a feedback value; out: a controller output; v. ofα、vβ: two-phase voltage of an alpha-beta coordinate system; v. ofa、vb、vc: a. b, c three-phase voltage; i.e. iα、iβ: two-phase current of an alpha-beta coordinate system; i.e. ia、ib、ic: a. b, c three-phase current; i.e. id、iq: two-phase current of a d-q coordinate system; v. ofd、vq: two-phase voltage of d-q coordinate system; e.g. of the typeα、eβ: two-phase back electromotive force of an alpha-beta coordinate system; thetar: a rotor position.
Detailed Description
The invention will be described in further detail below with reference to the following figures and specific examples:
1. the invention provides a high-frequency converter for high-speed motor technical drive, which uses FPGA to replace general DSP/ARM, designs a high-frequency converter main control based on Soc (System on chip), researches and develops a complete SVC (sensory Vector control) algorithm based on HDL (hardware description language), uses IP soft core to realize a motor control algorithm, increases the torque loop operation speed from the current 20kHz to 100kHz, correspondingly increases the highest output frequency of the frequency converter from the current 600Hz to 2500Hz, and can realize high-precision, high-efficiency and low-vibration speed control of a DC brushless motor and a magnetic synchronous motor.
2. The invention adopts a magnetic field orientation control algorithm to realize high-performance control on a permanent magnet motor, and the 'orientation' firstly solves the problem of accurate detection of the position of a rotor. And the second method comprises the following steps: a digital model of the motor is established without using a position sensor, the permanent magnet motor is regarded as a sensor, the input voltage of the motor is regarded as the excitation of the sensor, the feedback current of the motor is regarded as the response of the sensor, and the position of the rotor is accurately calculated on line through a high-level algorithm; the method has the advantages of high precision, high reliability and low cost, but the motor cannot work in a torque control mode and a position control mode.
3. Aiming at the problems of heat dissipation, electromagnetic interference, strong and weak point isolation and compatibility among product families of a high-frequency converter, the invention provides a product structure design method for isolation, heat dissipation, shielding and integrated molding.
Example 1:
as shown in fig. 1, most of high-speed motors are non-standard products, a high-frequency converter adopts direct-current power supply input, the voltage range of the input is set to be 24-400 Vdc, and the adaptability and application fields of the frequency converter to motors with various specifications are widened by wide-range bus voltage. The product of the invention belongs to a core functional component in the industrial field, and is completely compatible with the upper computers such as the current industrial personal computer, PLC, non-standard systems and the like, the functions of the interfaces of the upper computers in the system of figure 1 are shown in a table 1, the RS232 interfaces in the table are isolated from strong electricity, other interfaces are grounded with the upper computers and completely isolated from a drive control unit circuit, and the isolation voltage grade is 2.1 kV. The programmable communication interface can be set by a touch screen or a panel operator and can be configured into 3 RS485, one RS485 and one RS422 or 3 LVDS input/output, a communication protocol can be adjusted according to an upper computer, the scheme of integrating the programmable communication interface with an upper computer system is shown in figure 3, the scheme shown in figure 2.a) shows that analog quantity is used as speed instruction input, the scheme shown in figure 2.b) shows that digital quantity is used as speed input, the scheme shown in figure 2.c) controls a motor in a bus mode, and the scheme shown in figure 2.d) shows that the high-frequency converter is completely compatible with the conventional upper computer through the interface. The UART1 interfaces RS232 protocol with PC, and UART0 interfaces with touch screen by Modbus-RTU protocol.
Table 1: control interface and function for driver product
In the figure 1, the data acquisition unit, the IO unit and the programmable communication interface unit of the high-frequency converter are all designed with isolation interface circuits with the withstand voltage value of more than 2.1kV, and each functional module has the advantages of high response speed, high reliability and strong anti-interference capability; the synchronous high-speed operation of the data acquisition unit, the high-load operation unit and the high-frequency inverter is met.
The invention relates to the field of high-speed and high-performance drive control of permanent magnet motors, a single-chip FPGA is adopted as a main controller, a high-performance processor special for a high-frequency converter based on an Soc soft core is invented, the Soc system architecture of the high-frequency converter is shown in figure 3, and the sources of IP in the Soc system are divided into two types:
the free IP core provided by the third party comprises a soft-core processor, a master control board left side phase-locked loop PLL, an SPI interface, an SDRAM interface, a digital quantity input/output PIO and an asynchronous serial port UARTx (x is 0-4) IP core in an FPGA square frame in fig. 3, and forms a minimum FPGA system and a universal periphery, and the module can be replaced by a GPU (including a DSP/ARM/single chip microcomputer) on the occasion of low cost.
The IP core is independently developed, a shadow part on the right side in an FPGA block diagram in fig. 3 comprises a Modbus-RTU protocol IP core used for high-speed bus control and a series IP core of permanent magnet motor non-inductive vector control (SVC), small-batch and high-frequency calculation functional units in the SVC algorithm flow are instantiated into a special peripheral of the Soc, the Soc system is only responsible for initialization of the peripheral, process data reading and control of a motor running state machine FSM, the starting, running, stopping, parameter self-adaption and other processes of motor running are independently completed by the peripheral, the bus is not occupied, no interruption is caused, and the technical route can enable the Soc system to process the SVC algorithm at the speed of 120kHz at most in real time.
As shown in fig. 3, the FOC control dedicated peripheral in the Soc system includes a finite state machine FSM, an ADC interface, a Clarke transform, a Park transform, a back electromotive force observation period ABobsrv, a velocity filter GetVel, a velocity loop controller vPi, a current loop controller dPi/qPi, a Park inverse transform invPark, a Clarke inverse transform invClarke, a central symmetric vector PWM modulator SVM, and the like.
The controller controls the motor by reading and writing finite state machine FSM, the FSM soft core is a controlled finite state machine, the FSM core controls the ADC outside the chip to acquire feedback data required by the SVC algorithm at a high speed according to the time point shown in figure 4 in a control period, then controls the series SVC algorithm peripherals at the right side of figure 3 to execute the SVC algorithm in a chip from top to bottom in sequence, and finally controls the FGPA pin U by the SVM coreT/B、VT/B、WT/BAnd driving the off-chip high-frequency inverter bridge according to the time sequence of the figure 4, and repeatedly executing the steps in the next period.
The first step is as follows: analog quantity synchronous detection and coordinate transformation
The ADC interface soft core controls a peripheral multichannel synchronous ADC chip, and in order to prevent interference of a power device, sampling time is accurately located at a PWM midpoint, and as shown in FIG. 4, the acquired analog quantity comprises: three-phase current ia/b/cBus voltage VDCMotor temperature TempMOTORTemperature Temp of base of frequency converterVFDInputting analog quantity of 0-10V/4-20mA by an upper computer, performing amplitude equivalent Clarke transformation after sampling to obtain iα、iβAnd voltage uα、uβ
The Park soft core is based on the rotor position theta of the last control periodrRotation operation of coordinate axis to obtain AC and DC axis current components iq、id。
The second step is that: rotor position acquisition technique
The direct detection mode comprises the following steps: as shown in FIG. 1, the rotor position is directly acquired by a mechanical position sensor PG installed on the motor, and PG input signals are connected with a programmable communication interface of a general main control board.
An indirect detection mode: the observer is designed to calculate the position of the rotor through the input voltage and the feedback current of the motor, the permanent magnet motor is regarded as a sensor, the input voltage of the motor is regarded as the excitation of the sensor, the feedback current of the motor is regarded as the response of the sensor, the position of the rotor is accurately calculated on line through an algorithm, so that the directional control of a magnetic field is realized, and the high-precision control of the speed of the permanent magnet motor is realized under the condition that a mechanical position sensor is not used. The technical scheme is realized as follows:
stator single-phase winding circuit as shown in fig. 6, fig. 7 is a flow chart of stator single-phase winding current signals, L, R circuit G(s) presents low-pass characteristics to current, the discretization step in fig. 2 can be advanced, and a digital model is established according to detected parametersIn parallel with the ideal model g (z), the inverse electromotive force detection flowchart shown in fig. 8 is obtained.
The measured phase current I (z) of the upper branch in FIG. 8 can be expressed as
I(z)=(U(z)-E(z))G(z) (3)
In fig. 7, the parameters of the single-phase winding of the motor can be accurately measured, the current sampling frequency in the high-frequency converter is far higher than the bandwidth of G(s), and the digital model of the single-phase winding in fig. 9 is assumedThe step response of (a) accurately approximates the actual model G (z) of the motor in FIG. 7, i.e.
By substituting formula (6) into formula (5)
Writing the formula (7) into the transmission form shown in the formula (8)
(8) Formula system description observer equivalent model see fig. 9, it can be seen that the back electromotive force is independent of the excitation voltage, and according to the parameters of the model g (z) and the output frequency setting d (z) of the high frequency converter, so that | d (z) g (z) | > 1, thenRealize the inverseAnd (4) electric detection. Note that the system of fig. 9 shown in equation (8) cannot be directly implemented, and the algorithm shown in fig. 8 is executed by the ABobsv soft core, and as can be seen from the analysis of equation (3-8), the output result of the soft core is equivalent to executing the system of fig. 9.
In the running process of the motor, the observation shown in FIG. 8 is realized under an alpha-beta coordinate system, and the counter electromotive force e of the motor in running can be obtainedα、eβ
Adopting Newton dichotomy, computing the position of the rotor by the getVel soft kernel through coordinate axis rotation operation
Then theta is adjustedrInputting a filter shown in the formula (11), wherein delta is a filter coefficient, and delta is more than 0 and less than 1
Finally, the output of the filter of formula (11) is calculated again and input to vPi soft core as the motor feedback speed.
The third step: speed, flux linkage and torque control
The speed, flux linkage and torque control all adopt an anti-integral saturation PI control IP core, the control algorithm is shown in figure 5, the IP soft core is instantiated into three peripheral devices vPi, dPi and qPi in an SVC control algorithm, and the three peripheral devices vPi, dPi and qPi respectively correspond to a speed loop controller, a d-axis current loop controller and a q-axis current loop controller.
In the vPi speed loop, Ref is the speed command, Fb is the feedback speed, and the output Out is the q-axis command current iq;iqThe amplitude limit of (a) depends on the rated current of the motor;
dPi the current loop controller Ref is 0 and Fb is the feedback current i in equation (3)dThe output is Vd;
qPi Current Loop Ref is the velocity Loop output iqFb is a feedback current i in the formula (3)qThe output is Vq;
The amplitudes of the two current loop controller outputs Vd, Vq must satisfy:
the fourth step: voltage vector space synthesis
V to be output by dPi, qPi controllersd、vqTransformation from the rotor coordinate system to the stator coordinate system, thetarTaking the result of the second step (10) calculation
According to the power equivalent principle, the phase 2 is reduced into 3 phase voltage
According to the principle of voltage vector synthesis, the three-phase voltages can be represented again as
In FIG. 3, the inClarke unit eliminates v according to the formula (11-12)a、vb、vcCalculating the u, v, w phase PWM command pulse width TU、TV、TWThe SVM function unit is based on the pulse width command TU、TV、TWControl FPGA Pin U according to the timing sequence shown in FIG. 4T/B、VT/B、WT/BAnd outputting the centrosymmetric vector PWM, and driving the high-frequency inversion unit after isolation.
3. High-frequency converter isolation, heat dissipation, shielding and forming integrated design scheme
The industrialization scheme of the high-frequency converter needs to solve the following problems:
(1) heat dissipation problem, switching loss and on-state loss of high frequency converter power device;
(2) the shielding problem, high frequency and large current electromagnetic interference output by the frequency converter; the plane and the space between the strong current and the weak current are insulated;
(3) standardization, small-batch and multi-variety problems of customers in the industrialization process;
in consideration of the above problems, the invention provides an integrated design scheme for isolation, heat dissipation, shielding and molding, and the implementation method comprises the following steps:
the high-frequency converter design scheme is considered the converter system according to strong, weak electric separation, heat dissipation and anti-interference etc. factor, carries out the function and cuts apart, divide into a general main control board and a drive plate, and general main control board main function is: the method comprises the steps of receiving instructions of upper computers such as a panel operator, a touch screen, a PC (personal computer), a point-of-care or PLC (programmable logic controller) and the like, feeding back data, controlling a motor through a driving plate, collecting data of the motor in a running process in real time, and executing an SVC (static var compensator) algorithm. The general main control board shown in fig. 5 is composed of a high-performance MCU, a multi-channel ADC, an isolated digital IO, an isolated analog input, a programmable communication interface, an isolated DC/DC, and a UART interface. The main functions of the driving plate are: and the motor is controlled to output three-phase current, bus voltage, power semiconductor device temperature and motor temperature signals to the main control board. As shown in fig. 6, the driving board is composed of a surge voltage/current protection circuit, an isolated high-frequency three-phase inverter unit, an isolated bus voltage detection circuit, an isolated frequency converter/motor temperature detection circuit, an isolated three-phase current detection circuit, and an isolated switching power supply.
The universal main control board of the high-frequency converter and the two sides of the drive board are respectively arranged on the two sides of the mounting base, the universal main control board realizes the control analog quantity data of the read drive board and controls the high-frequency inversion unit through controlling the wire harness, and the structure has the advantages that
Heat radiation technical scheme
(1) The heat source power semiconductor on the driving plate is bonded on the high-heat-conduction and high-magnetic-conduction base through the heat conduction material, the thickness W of the heat dissipation base and the power of the heat dissipation fan are selected according to the power of the driving plate, and the heat dissipation base and the heat dissipation fan are cooled through the heat dissipation fins; (2) the base is fixed on a metal main board in the user case and transfers the heat of the base to the metal case; (3) the driving board PCB adopts a thick copper plate, a large area of copper is covered at the mounting position of the power semiconductor device, and a window through hole is additionally arranged, so that the heat dissipation capacity of the driving board is improved.
Shielding technical scheme
(1) The high-frequency converter system is divided into a general main control board and a drive board, so that strong and weak current isolation is realized; (2) the high-conductivity magnetic grounding base separates the driving board from the general main control board, and effectively shields the electromagnetic interference of the driving board on the main control board and the control line speed caused by high voltage and large current; (3) the universal main control board and the drive board PCB are respectively arranged on different ground planes such as a digital ground, an analog ground, a power ground and a shell, so that the problem of interference among signals is effectively solved; (4) the drive plate is grounded to the chassis through the mounting base.
Product standardization technical scheme
The power range of the high-frequency converter driving plate is 0.2-30 kW, and the following standardized technical scheme is adopted in the production of the high-frequency converter driving plate:
(1) standardization of installation specification
The series frequency converter adopts a unified universal control panel; the series of frequency converter driving boards adopt PCBs with uniform specifications, the difference among the driving boards is reflected in the difference among three components of a power semiconductor, a current sensor and an electrolytic capacitor, but the installation positions of the three components on the PCBs and the component packaging are completely consistent in the power range; in the integrated molding technology, as shown in fig. 7, the length and width of the base are completely consistent in the above power range, only the thickness W of the base changes according to the heat dissipation requirement of the high-frequency converter, the larger the power is, the larger the W is, the response is increased, and the base is also a mounting carrier for a universal control board, a drive board and a shell.
(2) System software flexible design
Selecting corresponding drive plate according to the power grade and rotation speed range of the motor, installing the drive plate and a universal plate according to the mode shown in figure 7, setting the universal plate by operating a touch screen, a panel operator, a PLC, an industrial personal computer or a personal computer, matching a high-frequency converter with different motors and drive product families of loads, and mainly setting parameters as
Table 1: hardware configuration of driver products
According to the design method, 2 PCBs can be used for realizing products in a full power range, standardized production is realized, the product applicability is improved, the product cost is reduced, a software system with specifications and flexibility is installed in a unified mode, the products can be guaranteed to be capable of being rapidly adaptive to the dynamic change of a motor market, different products with low cost and high performance can be produced in a short development period, the problems of small batch and multiple varieties of customers in the industrialization process are solved, and the survival capability and the competitiveness of the products are improved.
In order to verify the experimental effect of the invention, the high-frequency converter of the invention is used for driving a one-to-one 280W three-phase high-speed direct current brushless motor, a motor shaft is rigidly coupled with an impeller, the algorithm of equipment operation under the conditions of high speed and heavy load of a fan and the speed precision, vibration and efficiency are examined, the PWM carrier frequency is set as Tp60kHz, dead time Tdb300ns, bus voltage VdcWhen the voltage is 32V, the phase inductance of the motor is 23uH, the phase resistance is 0.174 Ω, the SVC is adopted, the control parameters are as shown in fig. 13, the motor speed is 60000rpm, the FPGA on-chip RAM is used for recording three-channel data at high speed, the experimental sampling frequency shown in fig. 20 is 3750Hz, and other experimental sampling frequencies are 6000 Hz.
The precise detection of current and voltage is the key point of non-inductive vector control for precisely identifying the position of a rotor, the current sensor in the invention adopts a precise linear hall sensor, the noise range is within +/-0.17A under the bandwidth of 120kHz at normal temperature, the three-phase current waveform of a DC brushless motor under the condition of 60000rpm and heavy load operation is shown in a graph 12, and the current curve is smooth, thereby proving that the isolation and shielding technical measures of the invention effectively eliminate electromagnetic interference, the ADC interface soft core controls the sampling of the ADC graph 4 at a moment when the switching noise is smaller, and the dv/dt and the di/dt noise are inhibited, so that the noise source of a detected signal is mainly linear hall per se, the signal waveform approaches to sine wave, and the problems of large torque ripple, large harmonic current and limited power when the DC motor is controlled by the traditional 3-hall and six-step method are effectively solved.
PWM command pulse width T given in FIG. 13U、TV、TWThe calculation is carried out by the inClarke soft core according to the output of the current loop dPi and qPi controllers according to the (11-12), so that TU、TV、TWThe fluctuation of the waveform depends on the disturbance of the load, the load of the high-speed fan is constant in a steady-state operation stage, the curve of fig. 13 is smooth, and the low-vibration technical performance of the high-frequency converter under the high-speed operation condition is indirectly shown.
The counter electromotive force of the direct current brushless motor is in a ladder shape, the traditional control method is that every two three-phase windings are conducted, namely, the three-phase windings are electrified at 120 degrees, and a jumping magnetic field with 60 degrees as step length is generated; in the present invention, T isU、 TV、TWThe voltage is converted according to the formula (12), the three-phase voltage waveform of the motor shown in fig. 14 can be obtained, the waveform is approximate to a sine wave, a 180-degree power-on mode is realized, and a continuously rotating magnetic field is generated, so that the high precision, the high efficiency and the low vibration of the permanent magnet motor control are ensured in principle.
FIG. 15 shows the input and output results of the observer of FIG. 8, with the ABobsv soft kernel computing e in real time driven by the sync pulsesα、eβThe viewer input v is given in the figureα、iαAnd output eαThe invention detects the alpha-beta axis back electromotive force component and calculates the rotor position theta by the formula (10)rTherefore, only the back electromotive force e is concerned when the parameters of the invention are setα、eβRelative proportion of fundamental component, irrespective of eα、eβAbsolute accuracy of (e), thus e in the figureαThe trapezoidal back electromotive force of the brushless DC motor for experiment is not presented, but approaches to the sine string, namely the fundamental wave of the trapezoidal back electromotive forceAnd (4) components.
getVel Soft core then pair eα、eβAdaptive filtering to obtain eαf、eβfAnd calculating thetarThe three synchronous waveforms are shown in FIG. 16, θrGood linearity and small waveform distortion.
In field oriented control, the current vector leads the rotor position by 90 ° to achieve maximum torque, and as can be seen from equation (9), the back emf phase also leads the rotor bit value by 90 °, i.e., ideally both are in the same direction. The current vector phase is accurately measurable, and the alpha-axis current i is respectively shown in the graph 17 from top to bottomαCounter electromotive force eαAnd the synchronous waveform of the torque angle (phase difference between the two waveforms), eαThe principle of value calculation is shown in fig. 8, which is the α -axis component of the ABobsv soft-kernel output in the Soc system, as can be seen. The counter electromotive force vector phase approaches the current vector phase, the torque angle fluctuates within the range of +/-2 degrees, the control effect approaches PG control, and the experimental result shows that: under the condition of not using a position sensor, the technical scheme of the invention for acquiring the position of the rotor has higher detection precision.
The speed precision experiments are divided into two groups, the sampling frequency is 3750Hz, 2000 points are recorded, the experimental result in the acceleration stage is shown in figure 18, and the command rotating speed, the feedback speed and the q-axis command current i are respectively arranged from top to bottomqr(Ref as soft core qPi), it can be seen that the feedback speed follows the commanded speed quickly and accurately, and the commanded current varies with the variation in the following error. The analysis of the experimental result of the steady state operation of the motor 60000rpm is shown in FIG. 19, and the speed error calculation mode in the graph is
Fig. 19 shows a speed error curve, and the speed accuracy of the fan for the high-frequency converter speed control experiment can reach +/-2 per thousand. The experimental result shows that the high-frequency converter keeps higher speed control precision and efficiency in the whole speed regulation range.
In order to record the process of speed stabilization and 60000rpm acceleration and deceleration within the full speed range of the motor, the Soc system sends q-axis current data to the touch screen through the UART0 serial port every 0.1s, and the waveform (converted into torque on the touch screen) is displayed on the touch screen in real time. The experimental steps are as follows: firstly, the motor is accelerated to 60000rpm, then the motor is decelerated and stopped, and then the value is 60000rpm is started, the method completely records the acceleration and deceleration waveform of the motor, the recording result is shown in figure 20, the left descending curve in the figure is the deceleration process, the right ascending curve is the acceleration process, the open-loop control is adopted below the open/closed loop critical frequency in the starting stage, the q-axis current cannot reflect the torque in the stage, after the critical frequency is passed, the position of the rotor is locked, the control mode is switched from the open-loop control mode to the magnetic field orientation control mode in the later and deceleration stages, the q-axis current curve is in the shape of a quadratic function, because the motor is used as a fan type load in an experiment, the torque is in direct proportion to the square of the speed, the high-frequency converter can track the size of the load in the full-speed range, the high efficiency and the accuracy of the control algorithm are embodied, and the torque curve is smooth, the torque ripple is small, and low vibration control in the full speed range is realized.
An integrated driving and detecting system of a permanent magnet motor comprises a driver (namely a frequency converter) and a data detecting module; the driver is used for driving the permanent magnet motor to rotate; the data detection module is a synchronous data detection module of an IP soft core based on the FPGA; the data collected by the data detection module comprises:
(1) ch0 speed setpoint wr(ii) a (2) Ch1 velocity feedback value wf(ii) a (3) CH2 q-axis command current Iq(ii) a (4) CH3 q-axis feedback current Iqf(ii) a (5) CH4 q-axis voltage command Vq(ii) a (6) CH5 d axis indicates current id(ii) a (7) CH6 d axis feedback current idf(ii) a (8) Ch7 d-axis voltage command Vd;(9)CH8 Vα (10)CH9 Vβ(ii) a (11) CHA A phase SVPWM pulse width PWMA; (12) CHB B phase SVPWM pulse width PWMB; (13) CHC phase SVPWM pulse width PWMC; (14) CHD ia;(15)CHE iβ;(16)CHF ib;(17)CHG ic(ii) a (18) CHH phase voltage amplitude Um(ii) a (19) CHI phase voltage phase(20) CHJ phase Current amplitude Im(ii) a (21) CHK phase current phase(22) CHL counter electromotive force amplitude Em(ii) a (23) CHM back emf phase(24) CHN torque angle, i.e.(25) CHO power angle, i.e(26) CHP locked rotor coefficient; (27) CHK a counter electromotive force waveform Eα(ii) a (28) CHR b counter electromotive force waveform Eβ(ii) a (29) CHS a Current estimation iα *(ii) a (30) The CHT rotor position theta (measured by the encoder when the sensor exists, and constantly 0 when the sensor does not exist); (31) measured speed w of CHU rotor0(encoder measurement is carried out when a sensor is available, and 0 is constantly carried out when no sensor is available); (32) CHV encoder line number Rev (encoder measurement with sensor, constant 65535 without sensor)
In the channel, PWMA/B/C is a given value, ia/B/C is a measured value, and w and theta are calculated values in a non-inductive vector control algorithm; in the presence of the PG control algorithm, the measured values are all calculated values.
Data that must be collected or calculated: the quantity which must be collected by the non-inductive vector control is ia/b/c; the rotor position θ must be acquired on this basis with PG (rotor position detector) control.
Calculating motor operation dynamic parameters based on the acquired data; the motor operation dynamic parameters comprise: load torque, winding equivalent resistance/inductance, motor active/reactive power, driver active/reactive power, torque parameters, motor speed, driver temperature, motor temperature, back emf, power angle, load angle.
The data output by the data detection module is stored in a local memory or output to a touch screen for display or output to an upper computer.
The motor static parameter identification module is also included;
the working process of the motor static parameter identification module is as follows: a tester sends a static parameter identification command (through an upper computer or a touch screen or a keyboard), a controller injects three-phase rotating high-frequency voltage under the condition of motor stalling according to the static parameter identification command, after current data are stable, excitation voltage and feedback current data are stored in an SRAM (static random access memory) arranged in the controller, and then stored synchronous data are read into an internal memory of an SOC (system on chip) system, and the SOC system calculates alternating-axis and direct-axis inductances, winding resistance, salient pole coefficients and an initial position of a rotor of the motor in an off-line mode according to a permanent magnet motor data model under an alpha-beta coordinate system of the permanent magnet motor.
The calculation process of the static parameters of the motor is as follows:
the mathematical model of the permanent magnet motor under an alpha-beta coordinate system is shown as the formula (1)
In the formula L1,L2Are respectively an AC and a DC axis inductor Ld,LqThe sum and difference of (c) are averaged, and the relationship can be expressed as:
measuring method, under the condition of motor locked-rotor state, the injection amplitude is UiAngular velocity of omegaiHigh frequency voltage, the excitation voltage can be expressed as
Angular frequency omega of excitation signal in the above formulaiThe winding inductance is far larger than the winding resistance R, and the first term of the formula (1) can be ignored; in the measurement process, the motor is locked up and rotated, and the last term of the formula (1) is 0; neglecting higher harmonic componentAn amount; after approximation, the response current of the motor can be expressed as
(6) Wherein the first term is constant and the second term has a frequency of 2 ΩiNote that formula (4) only considers fundamental waves and does not consider harmonics, and it can be known from the principle of the current conversion technique that the inverter circuit inevitably has integer harmonics k Ω of the output frequencyiIn order to improve the detection precision, an M-order digital wave trap is designed, and the sampling frequency of the system is set to be fpwmAnd the frequency conversion output excitation frequency is fiThen M can be selected as
M=l×fpwm/fi(l=1,2,3,…) (7)
Setting the excitation signal frequency fiCan be removed fpwmEnsuring that formula (7) M is an integer, the transfer function H (z) of the digital filter is shown as formula (8), the amplitude response of the M-order trap is shown as figure 7, in which the frequency k omega is showni (k=1, 2, …, 9) is mapped onto the zero point, i.e. the unit circle of the z-plane, of a digital filter which completely eliminates the frequency k ΩiAnd (k is 1, 2, …) fundamental wave and harmonic wave of each order.
The filter is characterized by all-pass characteristic to baseband signals, trap characteristic to fundamental wave and each harmonic signal of the frequency output by the frequency converter,is a given value and is a given value,in the process of high-frequency injection, clicking a 'Sample' button in figure 3 to store all variables in figure 3 into an SRAM according to the time sequence shown by 5, reading the voltage and current data of the SRAM by an Soc soft core processor, calculating the operation result of left data according to the formula (5-6), passing the data through a filter in figure (8), obtaining the direct current component value on the right side of the formula (6), then integrating the direct current component values (5-6), and calculating L1、L2Further, the equivalent resistance R and inductance L of the motor winding are obtainedd/qSalient pole coefficient L2/L1。
The permanent magnet motor integrated driving and detecting method is characterized in that the permanent magnet motor integrated driving and detecting system is adopted;
driving a permanent magnet motor through a driver;
and acquiring and calculating actual data by adopting a data detection module.
The high-speed synchronous data acquisition IP core is shown in the figure, the unit is a soft core functional module generated by instantiating a hardware description language, the right side is IP core input, clock and reset _ n are clock and reset input of an acquisition system, w _ r high/low level represents read/write SRAM, rdAddr is a write address pointer counter, synClk is a write synchronous signal, and the signal is set and determined by a human-computer interface and can be selected to be synchronous with a position ring, a speed ring or an acceleration ring; and sequentially acquiring data of all 32 channels in each position loop, speed loop or acceleration loop period. The left side is IP core output, smpFlag is SRAM data full flag bit, address is connected with peripheral SRAM input address, SRAM _ data is connected with peripheral SRAM data port, the port is bidirectional IO, dataout is SRAM output corresponding to address input rdAddr, CE _ n, OE _ n, UB _ n, LB _ n and WE _ n are memory read-write control signals
When the Soc system receives a sampling instruction sent by an upper computer, an SRAM write Enable signal Enable is set, and after ADC conversion is completed, a high-speed acquisition unit controls and generates CE _ n, OE _ n, UB _ n, LB _ n and WE _ n command waveforms according to a time sequence, CHx (x is 0, 1, 2.) is a channel address, and data selected by the channel address is located in the channel addressThe falling edge is written to SRAM at CHx partition number Page address,rising edge, CHx value plus 1, execute 2KAfter that, all variables are written into the corresponding partition, Page address Page adds 1, the above time sequence is repeated after the next sampling is finished, until SRAM is full, smpFlag mark position bit, once sampling command, data quantity of continuous sampling is 32 channel multiplied by 2KWord/channel x 16 bit/word 2K+9And (6) bit. K13, i.e. one acquisition command, the ip data acquisition process will acquire 4Mbit of data.
The above embodiments are only used for illustrating the computing ideas and features of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the contents of the present invention and implement the present invention accordingly, and the protection scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes and modifications made in accordance with the principles and concepts disclosed herein are intended to be included within the scope of the present invention.
Claims (6)
1. A high-frequency converter is characterized by comprising a controller, a signal acquisition circuit and a high-frequency inverter bridge; the signal acquisition circuit is connected with the controller; the controller is connected with the high-frequency inverter bridge through the isolation circuit;
the controller is provided with a core module; the core module comprises an MCU minimum system and a peripheral circuit;
the controller is also provided with a soft core control module; the soft core control module comprises a finite state machine FSM, an ADC synchronous acquisition unit (ADCinterface), a Clarke conversion unit, a Park conversion unit, a back electromotive force observer (ABobsrv), a speed filter (GetVel), a speed ring controller (vPi), a current ring controller (dPi/qPi), a Park inverse conversion unit (invPark), a Clarke inverse conversion unit (invClarke) and a central symmetry vector PWM modulator (SVM);
the controller sends out driving pulses through the centrosymmetric vector PWM modulator to drive the inverter to work.
2. High frequency converter according to claim 1,
finite state machine FSM: the method comprises the following steps that an FSM core firstly controls an ADC synchronous acquisition unit to acquire feedback data required by an SVC algorithm in a control period, then controls an SVC algorithm peripheral to execute the SVC algorithm in a chip in a sequence from top to bottom, and finally outputs control pulses to control a high-frequency inverter bridge outside the chip, and the steps are repeatedly executed in the next period;
the analog quantity acquired by the ADC synchronous acquisition unit comprises: three-phase current ia/b/cBus voltage VDCMotor temperature TempMOTORTemperature Temp of base of frequency converterVFDInputting 0-10V/4-20mA of analog quantity of a host computer;
the Clarke transformation unit is used for executing amplitude equivalent Clarke transformation to obtain iα、iβ
Wherein:
iA、iBand iCThree-phase currents are respectively;
iα、iβis two-phase current of an alpha-beta coordinate system of the motor;
the Park conversion unit is used for converting the rotor position theta according to the previous control periodrPerforming coordinate axis rotation operation to obtain AC and DC axis current components iq、id;
A back electromotive force observer (ABobsrv) for obtaining a back electromotive force;
whereinIs the output of the counter electromotive force observer; g (z) is a digital model of the single-phase winding of the motor, the input quantity of the digital model is the difference between the input phase voltage and the back electromotive force of the motor, and the output quantity is the phase current:
l, R is inductance and resistance of stator phase winding of motor, Tp is SVPWM period, D (z) is observer controller:
Kp=2ξω0L-R
KI=ω0LTs
ξ、ω0respectively the damping ratio and the undamped oscillation frequency of the counter electromotive force observer;
e (z) z transformation for counter electromotive force; kp and KI are proportional coefficients and integral coefficients;
the velocity filter (GetVel) is used to obtain the velocity d θ (n) of the nth sampling point, and the calculation formula is:
d θ (n) ═ θ (n) - θ (n-1), θ (n) and θ (n-1) are the rotor positions at the times n and n-1, respectively;
a speed loop controller (vPi), in the vPi speed loop, the given value Ref is a speed command, the feedback value Fb is a feedback speed, and the output Out is a q-axis command current iq;iqThe amplitude limit of (a) depends on the rated current of the motor;
current ring controller (dPi/qPi)
dPi the current loop controller has given value Ref of 0 and feedback value Fb of feedback current idThe output is Vd;
qPi Current Loop controller, given value Ref being speed Loop output iqThe feedback value Fb is the feedback current iqThe output is Vq;
The amplitudes of the two current loop controller outputs Vd, Vq must satisfy:
a clarke inverse transformation (invClarke) is used for the clarke inverse transformation, and the alpha-beta axis voltage vector is equivalently transformed into an a-b-c three-phase coordinate system;
vdc is the dc bus voltage and Tp is the SVPWM period.
3. A high-frequency converter according to claim 1, characterized in that it further comprises a Modbus-RTU protocol IP core for high-speed bus control.
4. The high frequency converter according to claim 1, further comprising a permanent magnet machine SVC IP core for determining the permanent magnet machine rotor position without a position sensor.
5. The high-frequency converter according to any one of claims 1 to 4, wherein the controller communicates with the upper computer through a serial port.
6. The high-frequency converter according to claim 5, characterized in that a control method of the high-frequency converter is a non-inductance vector control method;
soc (System on chip) based on FPGA is designed to be used as the main control of the high-frequency converter, and an FOC algorithm and an SVC (sensory Vector control) algorithm of a motor control algorithm are realized by adopting an IP soft core.
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