WO2021244669A1 - Compressor variable-frequency speed adjusting system and control method for direct-current bus voltage - Google Patents

Compressor variable-frequency speed adjusting system and control method for direct-current bus voltage Download PDF

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Publication number
WO2021244669A1
WO2021244669A1 PCT/CN2021/107064 CN2021107064W WO2021244669A1 WO 2021244669 A1 WO2021244669 A1 WO 2021244669A1 CN 2021107064 W CN2021107064 W CN 2021107064W WO 2021244669 A1 WO2021244669 A1 WO 2021244669A1
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WIPO (PCT)
Prior art keywords
bus voltage
input voltage
voltage
motor
rated
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PCT/CN2021/107064
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French (fr)
Chinese (zh)
Inventor
蒲波宇
甘鸿坚
何静飞
安伟国
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浙江鲲悟科技有限公司
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Publication of WO2021244669A1 publication Critical patent/WO2021244669A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
    • H02M5/40—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc
    • H02M5/42—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters
    • H02M5/44—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/01—Arrangements for reducing harmonics or ripples
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
    • H02M5/40—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc
    • H02M5/42—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters
    • H02M5/44—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac
    • H02M5/453—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M5/458—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M5/4585—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only having a rectifier with controlled elements
    • 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
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/40—Arrangements for reducing harmonics

Definitions

  • the invention relates to the field of frequency conversion, in particular to a compressor frequency conversion speed regulation system and a method for controlling the DC bus voltage.
  • the power is above 8kW in the application, generally use the three-phase AC power supply, the front stage uses the uncontrolled rectifier bridge for rectification, and the rear stage uses the IPM module (Intelligent Power Module, intelligent power module). )
  • IPM module Intelligent Power Module, intelligent power module.
  • the shortcomings of this system are that the diodes in the rectifier bridge are uncontrolled devices, and a large amount of low-order harmonic currents will be injected into the grid when the system is working; the second is that the DC bus voltage is uncontrollable, and as the load power increases, the bus voltage The volatility will also increase.
  • the speed regulation of permanent magnet synchronous motor generally takes the rated speed as the demarcation point, the constant flux frequency conversion speed is used below the rated speed, and the weak magnetic frequency conversion speed is used above the rated speed.
  • the field weakening speed increases, since the field current used for field weakening only does useless work, it will increase the loss of the motor and reduce the efficiency of the motor. If you want to keep the magnetic flux constant and increase the speed above the rated speed, the motor back EMF will inevitably increase. At this time, the output voltage of the inverter inverter module, that is, the terminal voltage of the motor must increase accordingly.
  • the prior art uses a software overmodulation algorithm, but the voltage amplitude that this method can increase is limited, and the motor performance can only be slightly improved.
  • the purpose of the present invention is to provide a compressor frequency conversion speed regulation system and a DC bus voltage control method, which is used to solve the problem of low-order harmonics and low system efficiency in the prior art. problem.
  • the present invention provides a method for controlling the DC bus voltage in a compressor frequency conversion speed regulation system.
  • the control method of the DC bus voltage in the compressor frequency conversion speed regulation system at least includes:
  • the DC bus voltage is output according to the AC input voltage and the motor speed.
  • the DC bus voltage is set to a fixed value higher than the peak value of the rated AC input voltage
  • the DC bus voltage is set to be higher than the peak value of the actual AC input voltage, and the DC bus voltage follows The actual AC input voltage changes;
  • the minimum value of the second preset ratio range is greater than or equal to the maximum value of the first preset ratio range.
  • the DC bus voltage is set to be higher than the actual AC input voltage , The DC bus voltage changes with the change of the actual AC input voltage;
  • the power switch tube in the rectifier module is turned off, and the uncontrolled rectification mode is entered.
  • the relationship curve between the motor speed and the DC bus voltage is calculated; the DC bus corresponding to the motor speed is obtained from the relationship curve Voltage; if the DC bus voltage is lower than the peak value of the actual AC input voltage, the DC bus voltage is adjusted to be higher than the peak value of the actual AC input voltage.
  • the method of calculating the relationship curve between the motor speed and the DC bus voltage includes:
  • the relationship curve is determined by connecting the first end point and the second end point.
  • the method for calculating the relationship curve between the motor speed and the DC bus voltage further includes: adding end points of the relationship curve based on actual test data, and determining the relationship curve after each end point is connected in sequence.
  • the field weakening speed-up mode is entered.
  • the present invention also provides a compressor frequency conversion speed regulation system, which implements the above-mentioned method for controlling the DC bus voltage in the compressor frequency conversion speed regulation system, and the compressor frequency conversion speed regulation system at least includes:
  • a rectifier module which receives an AC input voltage and converts the AC input voltage into a DC bus voltage
  • An inverter module connected to the output terminal of the rectifier module, and converts the DC bus voltage into a motor drive voltage
  • a motor connected to the output terminal of the inverter module, and driven by the motor drive voltage to run;
  • the control module is connected to the motor, the rectifier module and the inverter module, and is used to generate control signals of the rectifier module and the inverter module.
  • the rectification module is an active rectification module; or the rectification module includes a passive rectification unit and a boosting unit, and the boosting unit is connected to the output end of the passive rectification unit.
  • the active rectifier module is a VIENNA rectifier module.
  • the VIENNA rectifier module includes six diodes, three inductors, six power switches, and two sets of capacitors; each diode is connected in series in the same direction and then connected in parallel, and the connection node of the first group of series diodes passes through the first The inductor is connected to the first phase of the AC input voltage, the connection node of the second group of series diodes is connected to the second phase of the AC input voltage via the second inductor, and the connection node of the third group of series diodes is connected to the second phase of the AC input voltage via the third inductor.
  • each power switch tube is connected in reverse series in pairs between the connection node of each group of series diodes and the connection node of the two groups of capacitors.
  • the compressor frequency conversion speed regulation system and the DC bus voltage control method of the present invention have the following beneficial effects:
  • the front stage of the compressor frequency conversion speed regulation system of the present invention adopts an active rectifier module, which greatly reduces the low-order harmonics of the power grid.
  • the rectifier module is controlled to increase the DC bus voltage, so that the motor delays entering the field weakening zone and improves the efficiency of the motor.
  • the compressor frequency conversion speed regulation system and the DC bus voltage control method of the present invention integrate the permanent magnet synchronous motor's full speed range working conditions and AC input voltage fluctuations, so that the frequency conversion speed regulation system is in the most efficient working mode.
  • Figure 1 shows a schematic diagram of the structure of a compressor frequency conversion speed regulation system in the prior art.
  • Fig. 2 shows a schematic flow chart of the method for controlling the DC bus voltage in the compressor variable frequency speed regulation system of the present invention.
  • Figure 3 shows a schematic diagram of the structure of the compressor variable frequency speed regulation system of the present invention.
  • this embodiment provides a method for controlling the DC bus voltage in a compressor variable frequency speed regulation system.
  • the method for controlling the DC bus voltage in the compressor variable frequency speed regulation system includes:
  • the DC bus voltage is output according to the AC input voltage and the motor speed.
  • the method for controlling the DC bus voltage in the compressor frequency conversion speed regulation system specifically includes the following steps:
  • the DC bus voltage is further set based on the fluctuation range of the actual AC input voltage (through closed-loop control, the actual voltage of the DC bus is always Track the preset voltage of the DC bus).
  • the rectifier module is controlled to set the DC bus voltage Vbus to be higher than the peak value of the rated AC input voltage Vra, and the DC The bus voltage Vbus remains constant (fixed value), and will not become lower as the actual AC input voltage Vab becomes lower or as the load of the motor becomes larger, so that the efficiency of the subsequent inverter modules will also be obtained improve.
  • the rated AC input voltage Vra is set to 380V, and the DC bus voltage Vbus satisfies the following relationship:
  • the value of the rated AC input voltage Vra can be set according to actual conditions, and it will be different in different countries or regions.
  • the three-phase line voltage of the power grid in China is 380V, which will not be repeated here.
  • the DC bus voltage Vbus is set to 101% of the peak value of the rated AC input voltage Vra.
  • the DC bus voltage Vbus and the rated AC input voltage can be set as required
  • the proportional relationship of the peak value of Vra as an example, can be set to 100%-105% (not including the end point 100%, including the end point 105%), and is not limited to this embodiment.
  • the rectifier module is controlled to set the DC bus voltage Vbus to be higher than the actual AC input voltage Vab
  • the DC bus voltage Vbus changes with the change of the actual AC input voltage Vab, so as to ensure that the rectifier module can work normally. This is because the rectifier module has a boost function, so the DC bus voltage must be higher than the peak value of the actual AC input voltage before the rectifier module can work normally.
  • the DC bus voltage Vbus is set to 101% of the peak value of the actual AC input voltage Vab. In actual use, the DC bus voltage Vbus can be set as required.
  • the proportional relationship of the actual AC input voltage Vab peak value can be set to 100%-105% as an example (not including the terminal 0%, including the terminal 5%), and is not limited to this embodiment.
  • the power switch in the rectifier module is turned off, that is, the control module in the system does not output a PWM drive signal and outputs a fault signal.
  • the inverter side can run at reduced load or soft stop.
  • the fault signal includes, but is not limited to, an undervoltage protection signal and an overvoltage protection signal, which will not be repeated here.
  • each preset ratio range can be set according to actual needs, and the minimum value of the second preset ratio range is greater than or equal to the maximum value of the first preset ratio range, which will not be repeated here.
  • the rectifier module is controlled to increase the DC bus voltage Vbus, so that the motor delays entering the field weakening zone.
  • the relationship curve uses the motor speed as the abscissa and the DC bus voltage as the ordinate. More specifically, the first end point of the relationship curve is determined by using the rated speed of the motor and the preset value higher than the peak value of the rated AC input voltage Vra as the abscissa and ordinate.
  • the motor speed corresponds to the rated speed of the motor
  • the DC bus voltage Vbus corresponds to a preset value higher than the peak value of the rated AC input voltage Vra, so as to determine the first end of the relationship curve point.
  • the rated speed of the motor is 6000 rpm
  • the preset value is set to 101% of the peak value of the rated AC input voltage Vra.
  • the DC bus voltage Vbus and the The proportional relationship of the peak value of the rated AC input voltage Vra can be set to 100%-105% (not including the terminal 100%, including the terminal 105%), and is not limited to this embodiment.
  • the second end of the relationship curve is determined by the motor speed corresponding to the maximum value Vbus_max of the DC bus voltage and the maximum value Vbus_max of the DC bus voltage.
  • the DC bus voltage Vbus corresponds to the maximum value of the DC bus voltage Vbus_max
  • the motor speed corresponds to the motor speed when the maximum value of the DC bus voltage Vbus_max, so as to determine the relationship The second end of the curve.
  • first end point and the second end point are then connected to determine the relationship curve.
  • the first end point is connected to the second end point, and the straight line thus obtained is the relationship curve.
  • the endpoints of the relationship curve are added, and the curve obtained after each endpoint is connected in sequence is the relationship curve.
  • the number of added endpoints can be set according to needs, and will not be repeated here.
  • the DC bus voltage Vbus corresponding to the motor speed is obtained from the relationship curve according to the preset speed of the motor or the actual speed of the detected motor (through closed-loop control, the actual speed of the motor always tracks the preset speed of the motor).
  • the DC bus voltage Vbus meets the requirements, that is, if the DC bus voltage Vbus is lower than the peak value of the actual AC input voltage Vab, the DC bus voltage Vbus is adjusted to be higher than the actual AC input The peak value of the voltage Vab; otherwise, it will not be adjusted, and the value obtained on the relationship curve shall prevail; this will determine the DC bus voltage Vbus.
  • This embodiment adopts an active rectifier module, which greatly reduces the low-order harmonics of the power grid; when the speed is below the rated speed, the influence of the power grid is considered, and the efficiency of the inverter module is improved by controlling the DC bus voltage to change with the power grid; When the rated speed is above the rated speed, the rectifier module is controlled to increase the DC bus voltage, which delays the entry of the motor into the field weakening zone and improves the efficiency of the motor; comprehensive permanent magnet synchronous motor full speed range working conditions and AC input voltage fluctuations make the variable frequency speed regulation system In the most efficient working mode.
  • This embodiment provides a method for controlling the DC bus voltage in a compressor variable frequency speed regulation system.
  • the difference from the first embodiment is that when the actual AC input voltage Vab is at the second preset value of the rated AC input voltage Vra When fluctuating within the range of the ratio, different processing is performed according to different sub-intervals.
  • the rectifier module is controlled to set the DC bus voltage Vbus to be higher than the peak value of the rated AC input voltage Vra, and The DC bus voltage Vbus remains constant (fixed value).
  • the rectifier module is controlled to set the DC bus voltage Vbus higher than the The peak value of the actual AC input voltage Vab, and the DC bus voltage Vbus changes with the change of the actual AC input voltage Vab.
  • the range of the second sub-interval can be set according to needs, and the power switch tube in the rectifier module is turned off when the internal fluctuation is not limited to this embodiment, that is, the control module in the system does not output PWM
  • the drive signal enters the uncontrolled rectification mode.
  • the uncontrolled rectification mode can reduce the switching loss of the rectifier module;
  • the power switch tube in the rectifier module is turned off and a fault signal is output.
  • this embodiment provides a compressor frequency conversion speed regulation system 1, and the compressor frequency conversion speed regulation system 1 includes:
  • Rectifier module 11 inverter module 12, motor 13 and control module 14.
  • the rectifier module 11 receives an AC input voltage and converts the AC input voltage into a DC bus voltage Vbus.
  • the rectifier module 11 is a VIENNA rectifier module in an active rectifier module, and various variations of VIENNA topology are applicable to the rectifier module 11 of the present invention.
  • the rectifier module 11 includes six diodes, three inductors, six power switch tubes, and two sets of capacitors (the two sets of capacitors can be a single capacitor or a combination of multiple capacitors in series and parallel), and the upper and lower two sets of capacitors The capacitance value is the same.
  • Each diode is connected in parallel in series in the same direction, that is: the cathode of the first diode D1 is connected to the anode Vbus+ of the DC bus voltage, and the anode is connected to the cathode of the second diode D2; The anode is connected to the cathode Vbus- of the DC bus voltage; the cathode of the third diode D3 is connected to the anode Vbus+ of the DC bus voltage, and the anode is connected to the cathode of the fourth diode D4; The anode is connected to the negative pole Vbus- of the DC bus voltage; the cathode of the fifth diode D5 is connected to the positive pole Vbus+ of the DC bus voltage, and the anode is connected to the cathode of the sixth diode D6; The anode is connected to the cathode Vbus- of the DC bus voltage V.
  • connection node of the first diode D1 and the second diode D2 is connected to the first phase L1 of the AC input voltage, and the third diode D3 and the fourth diode D4 are connected to each other.
  • the connection node is connected to the second phase L2 of the AC input voltage, and the connection node of the fifth diode D5 and the sixth diode D6 is connected to the third phase L3 of the AC input voltage.
  • Each phase of the AC input voltage is input through an inductor (the first inductor L11, the second inductor L12, and the third inductor L13) respectively.
  • the first group of capacitors C1 and the second group of capacitors C2 are connected in series and connected between the positive pole Vbus+ and the negative pole Vbus- of the DC bus voltage.
  • Each power switch tube is connected in reverse series in pairs, respectively, between the connection node of each group of series diodes and the connection node of the two sets of capacitors, that is: the collector of the first power switch tube Q11 is connected to the first diode D1 With the connection node of the second diode D2, the emitter is connected to the emitter of the second power switch Q12; the collector of the second power switch Q12 is connected to the first group of capacitors C1 and the second The connection node of the group capacitor C2; the collector of the third power switch Q13 is connected to the connection node of the third diode D3 and the fourth diode D4, and the emitter is connected to the emitter of the fourth power switch Q14 The collector of the fourth power switch tube Q14 is connected to the connection node of the first group of capacitors C1 and the second group of capacitors
  • the power grid in this embodiment is a three-phase four-wire system (three live wires and one ground wire). If it is a three-phase five-wire system (three live wires, one neutral wire and one ground wire), the neutral wire is connected to two sets of capacitors. Connection node.
  • each power switch tube adopts an insulated gate bipolar transistor, and the type of each power switch tube can be set according to needs in actual use.
  • the rectifier module 11 can be any controllable active rectifier module; it can also include a passive rectifier unit and a booster unit, the booster unit is connected to the output end of the passive rectifier unit; in order to achieve controllability Rectification is not limited to this embodiment.
  • the inverter module 12 is connected to the output terminal of the rectifier module 11, and converts the DC bus voltage Vbus into a motor drive voltage.
  • the six power switch tubes of the inverter module 12 constitute a three-phase inverter bridge, wherein the seventh power switch tube Q21 and the eighth power switch tube Q22 are connected in series to the DC bus voltage Between the positive pole Vbus+ of the DC bus voltage and the negative pole Vbus- of the DC bus voltage (the collector of the seventh power switch tube Q21 is connected to the positive pole Vbus+ of the DC bus voltage, and the emitter is connected to the collector of the eighth power switch tube Q22.
  • the emitter of the eighth power switch tube Q22 is connected to the negative pole Vbus-) of the DC bus voltage;
  • the ninth power switch tube Q23 and the tenth power switch tube Q24 are connected in series to the positive pole Vbus+ of the DC bus voltage and the Between the negative pole Vbus- of the DC bus voltage (the connection port is the same as the seventh power switch Q21 and the eighth power switch Q22, and will not be repeated here);
  • the eleventh power switch Q25 and the first Twelve power switch tubes Q26 are connected in series between the positive pole Vbus+ of the DC bus voltage and the negative pole Vbus- of the DC bus voltage (the connection port is the same as the seventh power switch tube Q21 and the eighth power switch tube Q22 , Which will not be repeated here); each power switch tube in the inverter module 12 is connected to a control signal.
  • each power switch tube in the inverter module 12 is an insulated gate bipolar transistor, and the type of each power switch tube can be set as required in actual use.
  • the inverter module 12 can choose any structure according to needs, and is not limited to this embodiment.
  • the motor 13 is connected to the output terminal of the inverter module 12, and is driven by the motor driving voltage.
  • the motor 13 is a permanent magnet synchronous motor.
  • a three-phase alternating current is applied to the three-phase stator windings of the motor, a rotating magnetic field will be generated, and the rotating magnetic field will drive the rotor to rotate synchronously.
  • the motor 13 may also be other three-phase motors such as an AC asynchronous motor, which will not be repeated here.
  • control module 14 is connected to the motor 13, the rectifier module 11 and the inverter module 12 to generate control signals of the rectifier module 11 and the inverter module 12.
  • control module 14 collects the AC input voltage and the signal on the motor 13, and controls the rectifier module 11 and the inverter module 12 to implement the first embodiment or the second embodiment.
  • the control method of the DC bus voltage in the compressor frequency conversion speed regulation system of the compressor realizes the speed regulation of the motor 13.
  • the first embodiment and the second embodiment which will not be repeated here.
  • the compressor frequency conversion speed regulation system of this embodiment greatly reduces the low-order harmonics of the power grid and improves the system efficiency.
  • the compressor frequency conversion speed regulation system (including the controlled motor) is always in the highest efficiency working mode, which is suitable for industrial applications .
  • the present invention provides a compressor frequency conversion speed regulation system and a DC bus voltage control method, including: a rectifier module, which receives an AC input voltage and converts the AC input voltage into a DC bus voltage; an inverter module , Connected to the output terminal of the rectifier module to convert the DC bus voltage into a motor drive voltage; a motor, connected to the output terminal of the inverter module, and operated by the motor drive voltage; a control module, connected to the The motor, the rectifier module, and the inverter module are used to generate control signals of the rectifier module and the inverter module; when the motor runs below the rated speed, the DC bus voltage is output according to the AC input voltage; When the motor runs above the rated speed, the DC bus voltage is output according to the AC input voltage and the speed of the motor.
  • the front stage of the compressor variable frequency speed regulation system of the present invention adopts an active rectifier module, which greatly reduces the low-order harmonics of the power grid; when the speed is below the rated speed, the influence of the power grid is considered, and the DC bus voltage is controlled to change with the power grid. , Improve the efficiency of the inverter module; when the rated speed is higher than the rated speed, the rectifier module is controlled to increase the DC bus voltage, which delays the entry of the motor into the field weakening zone and improves the efficiency of the motor; comprehensive permanent magnet synchronous motor full speed range working conditions and AC The input voltage fluctuates, so that the variable frequency speed regulation system is in the most efficient working mode. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial value.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Ac Motors In General (AREA)

Abstract

A compressor variable-frequency speed adjusting system and a control method for a direct-current bus voltage, comprising: a rectifier module, for converting an alternating-current input voltage into a direct-current bus voltage; an inverter module, for converting the direct-current bus voltage into an electric motor driving voltage; an electric motor, driven by the electric motor driving voltage to operate; and a control module, used for adjusting the direct-current bus voltage outputted by the rectifier module. When the electric motor is operating below a rated rotational speed, the direct-current bus voltage is outputted on the basis of the alternating-current input voltage; and, when the electric motor is operating over the rated rotational speed, the direct-current bus voltage is outputted on the basis of the alternating-current input voltage and of the rotational speed of the electric motor. The control method greatly reduces low-order harmonics of an electrical grid, increases system efficiency, and puts the variable-frequency speed adjusting system in the most efficient work mode.

Description

压缩机变频调速系统及直流母线电压的控制方法Compressor frequency conversion speed regulation system and DC bus voltage control method 技术领域Technical field
本发明涉及变频领域，特别是涉及一种压缩机变频调速系统及直流母线电压的控制方法。The invention relates to the field of frequency conversion, in particular to a compressor frequency conversion speed regulation system and a method for controlling the DC bus voltage.
背景技术Background technique
现有的压缩机变频调速系统中，功率在8kW以上的应用场合，一般采用三相交流电源供电，前级采用不控整流桥做整流，后级采用IPM模块(Intelligent Power Module，智能功率模块)做三相逆变为电机提供交流输入，如图1所示。此系统的缺点，一是整流桥中二极管属于不控器件，系统工作时会给电网注入大量的低次谐波电流；二是直流母线电压不可控，且随着负载功率的增加，母线电压的波动也会加大。In the existing compressor variable frequency speed regulation system, the power is above 8kW in the application, generally use the three-phase AC power supply, the front stage uses the uncontrolled rectifier bridge for rectification, and the rear stage uses the IPM module (Intelligent Power Module, intelligent power module). ) Do a three-phase inverter to provide AC input for the motor, as shown in Figure 1. The shortcomings of this system are that the diodes in the rectifier bridge are uncontrolled devices, and a large amount of low-order harmonic currents will be injected into the grid when the system is working; the second is that the DC bus voltage is uncontrollable, and as the load power increases, the bus voltage The volatility will also increase.
永磁同步电机的调速一般以额定转速为分界点，额定转速以下采用恒磁通变频调速，额定转速以上采用弱磁变频调速。弱磁升速时，由于用于弱磁的励磁电流只做无用功，因此会导致电机的损耗增加，电机的效率就会变低。额定转速以上若想维持磁通不变而能够升高转速，那么电机反电动势必然会增大，此时变频器逆变模块的输出电压也即电机的端电压就必须随之增大。现有技术采用软件过调制的算法，但此方法所能提升的电压幅值有限，电机性能只能略有改善。The speed regulation of permanent magnet synchronous motor generally takes the rated speed as the demarcation point, the constant flux frequency conversion speed is used below the rated speed, and the weak magnetic frequency conversion speed is used above the rated speed. When the field weakening speed increases, since the field current used for field weakening only does useless work, it will increase the loss of the motor and reduce the efficiency of the motor. If you want to keep the magnetic flux constant and increase the speed above the rated speed, the motor back EMF will inevitably increase. At this time, the output voltage of the inverter inverter module, that is, the terminal voltage of the motor must increase accordingly. The prior art uses a software overmodulation algorithm, but the voltage amplitude that this method can increase is limited, and the motor performance can only be slightly improved.
因此，如何减小电网的低次谐波、提高变频调速系统的效率，已成为本领域技术人员亟待解决的问题之一。Therefore, how to reduce the low-order harmonics of the power grid and improve the efficiency of the frequency conversion speed regulation system has become one of the problems to be solved by those skilled in the art.
发明内容Summary of the invention
鉴于以上所述现有技术的缺点，本发明的目的在于提供一种压缩机变频调速系统及直流母线电压的控制方法，用于解决现有技术中电网低次谐波大、系统效率低等问题。In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a compressor frequency conversion speed regulation system and a DC bus voltage control method, which is used to solve the problem of low-order harmonics and low system efficiency in the prior art. problem.
为实现上述目的及其他相关目的，本发明提供一种压缩机变频调速系统中直流母线电压的控制方法，所述压缩机变频调速系统中直流母线电压的控制方法至少包括：In order to achieve the above and other related purposes, the present invention provides a method for controlling the DC bus voltage in a compressor frequency conversion speed regulation system. The control method of the DC bus voltage in the compressor frequency conversion speed regulation system at least includes:
当电机运行在额定转速以下时，根据交流输入电压输出直流母线电压；When the motor is running below the rated speed, the DC bus voltage is output according to the AC input voltage;
当所述电机运行在所述额定转速以上时，根据所述交流输入电压及电机转速输出所述直流母线电压。When the motor runs above the rated speed, the DC bus voltage is output according to the AC input voltage and the motor speed.
可选地，当所述电机运行在所述额定转速以下时，Optionally, when the motor runs below the rated speed,
若实际交流输入电压在额定交流输入电压的第一预设比例范围内波动，则所述直流母线电压设置为高于所述额定交流输入电压峰值的固定值；If the actual AC input voltage fluctuates within the first preset ratio range of the rated AC input voltage, the DC bus voltage is set to a fixed value higher than the peak value of the rated AC input voltage;
若所述实际交流输入电压在所述额定交流输入电压的第二预设比例范围内波动，则所述直流母线电压设置为高于所述实际交流输入电压的峰值，所述直流母线电压随着所述实际交流输入电压的变化而变化；If the actual AC input voltage fluctuates within the second preset ratio range of the rated AC input voltage, the DC bus voltage is set to be higher than the peak value of the actual AC input voltage, and the DC bus voltage follows The actual AC input voltage changes;
若所述实际交流输入电压在所述额定交流输入电压的第一预设比例范围及第二预设比例范围之外波动，则关断整流模块中的功率开关管，并输出故障信号；If the actual AC input voltage fluctuates outside the first preset ratio range and the second preset ratio range of the rated AC input voltage, turn off the power switch tube in the rectifier module and output a fault signal;
其中，所述第二预设比例范围的最小值大于等于所述第一预设比例范围的最大值。Wherein, the minimum value of the second preset ratio range is greater than or equal to the maximum value of the first preset ratio range.
更可选地，当所述实际交流输入电压在所述额定交流输入电压的第二预设比例范围的第一子区间内波动时，所述直流母线电压设置为高于所述实际交流输入电压的峰值，所述直流母线电压随着所述实际交流输入电压的变化而变化；More optionally, when the actual AC input voltage fluctuates within the first sub-interval of the second preset ratio range of the rated AC input voltage, the DC bus voltage is set to be higher than the actual AC input voltage , The DC bus voltage changes with the change of the actual AC input voltage;
当所述实际交流输入电压在所述额定交流输入电压的第二预设比例范围的第二子区间内波动时，关断整流模块中的功率开关管，进入不控整流模式。When the actual AC input voltage fluctuates within the second sub-interval of the second preset ratio range of the rated AC input voltage, the power switch tube in the rectifier module is turned off, and the uncontrolled rectification mode is entered.
更可选地，当所述电机运行在所述额定转速以上时，计算所述电机转速与所述直流母线电压的关系曲线；从所述关系曲线上得到所述电机转速对应的所述直流母线电压；若所述直流母线电压低于实际交流输入电压的峰值，则将所述直流母线电压调整为高于实际交流输入电压的峰值。More optionally, when the motor runs above the rated speed, the relationship curve between the motor speed and the DC bus voltage is calculated; the DC bus corresponding to the motor speed is obtained from the relationship curve Voltage; if the DC bus voltage is lower than the peak value of the actual AC input voltage, the DC bus voltage is adjusted to be higher than the peak value of the actual AC input voltage.
更可选地，计算所述电机转速与所述直流母线电压的关系曲线的方法包括：More optionally, the method of calculating the relationship curve between the motor speed and the DC bus voltage includes:
以电机额定转速及高于所述额定交流输入电压峰值的预设值作为横纵坐标确定所述关系曲线的第一端点；Determine the first end point of the relationship curve by using the rated speed of the motor and a preset value higher than the peak value of the rated AC input voltage as the abscissa and ordinate;
以所述直流母线电压的最大值及所述直流母线电压的最大值对应的电机转速确定所述关系曲线的第二端点；Determining the second end point of the relationship curve by using the maximum value of the DC bus voltage and the motor speed corresponding to the maximum value of the DC bus voltage;
连接所述第一端点及所述第二端点确定所述关系曲线。The relationship curve is determined by connecting the first end point and the second end point.
更可选地，计算所述电机转速与所述直流母线电压的关系曲线的方法还包括：基于实际测试数据增加所述关系曲线的端点，各端点依次连接后确定所述关系曲线。More optionally, the method for calculating the relationship curve between the motor speed and the DC bus voltage further includes: adding end points of the relationship curve based on actual test data, and determining the relationship curve after each end point is connected in sequence.
更可选地，当所述直流母线电压达到直流母线电压最大值时，进入弱磁升速模式。More optionally, when the DC bus voltage reaches the maximum value of the DC bus voltage, the field weakening speed-up mode is entered.
为实现上述目的及其他相关目的，本发明还提供一种压缩机变频调速系统，执行上述的压缩机变频调速系统中直流母线电压的控制方法，所述压缩机变频调速系统至少包括：In order to achieve the above and other related purposes, the present invention also provides a compressor frequency conversion speed regulation system, which implements the above-mentioned method for controlling the DC bus voltage in the compressor frequency conversion speed regulation system, and the compressor frequency conversion speed regulation system at least includes:
整流模块，接收交流输入电压，并将所述交流输入电压转化为直流母线电压；A rectifier module, which receives an AC input voltage and converts the AC input voltage into a DC bus voltage;
逆变模块，连接所述整流模块的输出端，将所述直流母线电压转换为电机驱动电压；An inverter module, connected to the output terminal of the rectifier module, and converts the DC bus voltage into a motor drive voltage;
电机，连接于所述逆变模块的输出端，受所述电机驱动电压的驱动运转；A motor, connected to the output terminal of the inverter module, and driven by the motor drive voltage to run;
控制模块，连接所述电机、所述整流模块及所述逆变模块，用于产生所述整流模块及所 述逆变模块的控制信号。The control module is connected to the motor, the rectifier module and the inverter module, and is used to generate control signals of the rectifier module and the inverter module.
可选地，所述整流模块为有源整流模块；或所述整流模块包括无源整流单元及升压单元，所述升压单元连接于所述无源整流单元的输出端。Optionally, the rectification module is an active rectification module; or the rectification module includes a passive rectification unit and a boosting unit, and the boosting unit is connected to the output end of the passive rectification unit.
更可选地，所述有源整流模块为VIENNA整流模块。More optionally, the active rectifier module is a VIENNA rectifier module.
更可选地，所述VIENNA整流模块包括六个二极管、三个电感、六个功率开关管及两组电容；各二极管两两同向串联后并联，第一组串联二极管的连接节点经由第一电感连接所述交流输入电压的第一相，第二组串联二极管的连接节点经由第二电感连接所述交流输入电压的第二相，第三组串联二极管的连接节点经由第三电感连接所述交流输入电压的第三相；两组电容串联后与各组串联二极管并联；各功率开关管两两反向串联后分别连接于各组串联二极管的连接节点与两组电容的连接节点之间。More optionally, the VIENNA rectifier module includes six diodes, three inductors, six power switches, and two sets of capacitors; each diode is connected in series in the same direction and then connected in parallel, and the connection node of the first group of series diodes passes through the first The inductor is connected to the first phase of the AC input voltage, the connection node of the second group of series diodes is connected to the second phase of the AC input voltage via the second inductor, and the connection node of the third group of series diodes is connected to the second phase of the AC input voltage via the third inductor. The third phase of the AC input voltage; the two groups of capacitors are connected in series and connected in parallel with each group of series diodes; each power switch tube is connected in reverse series in pairs between the connection node of each group of series diodes and the connection node of the two groups of capacitors.
如上所述，本发明的压缩机变频调速系统及直流母线电压的控制方法，具有以下有益效果：As mentioned above, the compressor frequency conversion speed regulation system and the DC bus voltage control method of the present invention have the following beneficial effects:
1、本发明的压缩机变频调速系统的前级采用有源整流模块，大大减小了电网的低次谐波。1. The front stage of the compressor frequency conversion speed regulation system of the present invention adopts an active rectifier module, which greatly reduces the low-order harmonics of the power grid.
2、本发明的压缩机变频调速系统及直流母线电压的控制方法在额定转速以下时，考虑了电网的影响，通过控制直流母线电压随着电网变化，提高了逆变模块的效率。2. When the compressor frequency conversion speed regulation system and the DC bus voltage control method of the present invention are below the rated speed, the influence of the power grid is considered, and the efficiency of the inverter module is improved by controlling the DC bus voltage to change with the power grid.
3、本发明的压缩机变频调速系统及直流母线电压的控制方法在额定转速以上时，通过控制整流模块升高直流母线电压，使得电机推迟进入弱磁区，提高了电机的效率。3. When the compressor frequency conversion speed regulation system and the DC bus voltage control method of the present invention are above the rated speed, the rectifier module is controlled to increase the DC bus voltage, so that the motor delays entering the field weakening zone and improves the efficiency of the motor.
4、本发明的压缩机变频调速系统及直流母线电压的控制方法综合永磁同步电机全速度范围工况及交流输入电压波动，使得变频调速系统处于最高效率的工作模式。4. The compressor frequency conversion speed regulation system and the DC bus voltage control method of the present invention integrate the permanent magnet synchronous motor's full speed range working conditions and AC input voltage fluctuations, so that the frequency conversion speed regulation system is in the most efficient working mode.
附图说明Description of the drawings
图1显示为现有技术中的压缩机变频调速系统的结构示意图。Figure 1 shows a schematic diagram of the structure of a compressor frequency conversion speed regulation system in the prior art.
图2显示为本发明的压缩机变频调速系统中直流母线电压的控制方法的流程示意图。Fig. 2 shows a schematic flow chart of the method for controlling the DC bus voltage in the compressor variable frequency speed regulation system of the present invention.
图3显示为本发明的压缩机变频调速系统的结构示意图。Figure 3 shows a schematic diagram of the structure of the compressor variable frequency speed regulation system of the present invention.
元件标号说明Component label description
1                      压缩机变频调速系统1 Compressor frequency conversion speed regulation system
11                     整流模块11 Rectifier module
12                     逆变模块12 Inverter module
13                     电机13 Motor
14                     控制模块14 Control module
具体实施方式detailed description
以下通过特定的具体实例说明本发明的实施方式，本领域技术人员可由本说明书所揭露的内容轻易地了解本发明的其他优点与功效。本发明还可以通过另外不同的具体实施方式加以实施或应用，本说明书中的各项细节也可以基于不同观点与应用，在没有背离本发明的精神下进行各种修饰或改变。The following describes the implementation of the present invention through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.
请参阅图2～图3。需要说明的是，本实施例中所提供的图示仅以示意方式说明本发明的基本构想，遂图式中仅显示与本发明中有关的组件而非按照实际实施时的组件数目、形状及尺寸绘制，其实际实施时各组件的型态、数量及比例可为一种随意的改变，且其组件布局型态也可能更为复杂。Please refer to Figure 2 to Figure 3. It should be noted that the illustrations provided in this embodiment only illustrate the basic idea of the present invention in a schematic manner, and the figures only show the components related to the present invention instead of the number, shape, and shape of the components in actual implementation. For size drawing, the type, quantity, and ratio of each component can be changed at will during actual implementation, and the component layout type may also be more complicated.
实施例一Example one
如图2所示，本实施例提供一种压缩机变频调速系统中直流母线电压的控制方法，所述压缩机变频调速系统中直流母线电压的控制方法包括：As shown in Figure 2, this embodiment provides a method for controlling the DC bus voltage in a compressor variable frequency speed regulation system. The method for controlling the DC bus voltage in the compressor variable frequency speed regulation system includes:
当电机运行在额定转速以下时，根据交流输入电压输出直流母线电压；When the motor is running below the rated speed, the DC bus voltage is output according to the AC input voltage;
当所述电机运行在所述额定转速以上时，根据所述交流输入电压及电机转速输出所述直流母线电压。When the motor runs above the rated speed, the DC bus voltage is output according to the AC input voltage and the motor speed.
在本实施例中，所述压缩机变频调速系统中直流母线电压的控制方法具体包括以下步骤：In this embodiment, the method for controlling the DC bus voltage in the compressor frequency conversion speed regulation system specifically includes the following steps:
1、当所述电机运行在所述额定转速以下时，考虑电网的影响，基于实际交流输入电压的波动范围进一步设定所述直流母线电压(通过闭环控制，所述直流母线的实际电压总是跟踪直流母线预设电压)。1. When the motor is running below the rated speed, considering the influence of the power grid, the DC bus voltage is further set based on the fluctuation range of the actual AC input voltage (through closed-loop control, the actual voltage of the DC bus is always Track the preset voltage of the DC bus).
具体地，若实际交流输入电压Vab在额定交流输入电压Vra第一预设比例范围内(在本实施例中，所述预设比例范围设定为80％～120％，在实际使用中可根据需要设定所述预设比例范围，不以本实施例为限)波动，则控制整流模块以将所述直流母线电压Vbus设置为高于所述额定交流输入电压Vra的峰值，且所述直流母线电压Vbus保持恒定(固定值)，而不会随着所述实际交流输入电压Vab变低或者随着所述电机的负载变大而相应变低，如此则后续逆变模块的效率也会得到改善。这是因为，如果直流母线电压变低，则逆变侧调制度会变大，如此导通损耗就会变大。在本实施例中，所述额定交流输入电压Vra设定为380V，则所述直流母线电压Vbus满足如下关系式：Specifically, if the actual AC input voltage Vab is within the first preset ratio range of the rated AC input voltage Vra (in this embodiment, the preset ratio range is set to 80% to 120%, which can be based on actual use The preset ratio range needs to be set, not limited to this embodiment), the rectifier module is controlled to set the DC bus voltage Vbus to be higher than the peak value of the rated AC input voltage Vra, and the DC The bus voltage Vbus remains constant (fixed value), and will not become lower as the actual AC input voltage Vab becomes lower or as the load of the motor becomes larger, so that the efficiency of the subsequent inverter modules will also be obtained improve. This is because if the DC bus voltage becomes lower, the modulation degree of the inverter side will become larger, so the conduction loss will become larger. In this embodiment, the rated AC input voltage Vra is set to 380V, and the DC bus voltage Vbus satisfies the following relationship:
Vbus＝Vra*1.414*1.01＝380*1.414*1.01＝543VVbus＝Vra*1.414*1.01＝380*1.414*1.01＝543V
需要说明的是，所述额定交流输入电压Vra的值可根据实际情况进行设置，不同的国家 或地区会有不同，例如中国的电网电源三相制线电压为380V，在此不一一赘述。在本实施例中，所述直流母线电压Vbus设定为所述额定交流输入电压Vra峰值的101％，在实际使用中，可根据需要设定所述直流母线电压Vbus与所述额定交流输入电压Vra峰值的比例关系，作为示例可设定为100％～105％(不包括端点100％，包括端点105％)，不以本实施例为限。It should be noted that the value of the rated AC input voltage Vra can be set according to actual conditions, and it will be different in different countries or regions. For example, the three-phase line voltage of the power grid in China is 380V, which will not be repeated here. In this embodiment, the DC bus voltage Vbus is set to 101% of the peak value of the rated AC input voltage Vra. In actual use, the DC bus voltage Vbus and the rated AC input voltage can be set as required The proportional relationship of the peak value of Vra, as an example, can be set to 100%-105% (not including the end point 100%, including the end point 105%), and is not limited to this embodiment.
具体地，若所述实际交流输入电压Vab在所述额定交流输入电压Vra的第二预设比例范围内(在本实施例中，所述预设比例范围设定为100％～120％，在实际使用中可根据需要设定所述预设比例范围，不以本实施例为限)波动，则控制所述整流模块以将所述直流母线电压Vbus设置为高于所述实际交流输入电压Vab的峰值，且所述直流母线电压Vbus随着所述实际交流输入电压Vab的变化而变化，以此保证所述整流模块可以正常工作。这是因为，整流模块具有升压功能，因此直流母线电压必须高于实际交流输入电压的峰值时，整流模块才能正常工作。Specifically, if the actual AC input voltage Vab is within the second preset ratio range of the rated AC input voltage Vra (in this embodiment, the preset ratio range is set to 100% to 120%, In actual use, the preset ratio range can be set according to needs, and this embodiment is not limited to fluctuations, then the rectifier module is controlled to set the DC bus voltage Vbus to be higher than the actual AC input voltage Vab And the DC bus voltage Vbus changes with the change of the actual AC input voltage Vab, so as to ensure that the rectifier module can work normally. This is because the rectifier module has a boost function, so the DC bus voltage must be higher than the peak value of the actual AC input voltage before the rectifier module can work normally.
需要说明的是，在本实施例中，所述直流母线电压Vbus设定为所述实际交流输入电压Vab峰值的101％，在实际使用中，可根据需要设定所述直流母线电压Vbus与所述实际交流输入电压Vab峰值的比例关系，作为示例可设定为100％～105％(不包括端点0％，包括端点5％)，不以本实施例为限。It should be noted that, in this embodiment, the DC bus voltage Vbus is set to 101% of the peak value of the actual AC input voltage Vab. In actual use, the DC bus voltage Vbus can be set as required. The proportional relationship of the actual AC input voltage Vab peak value can be set to 100%-105% as an example (not including the terminal 0%, including the terminal 5%), and is not limited to this embodiment.
具体地，若所述实际交流输入电压Vab在所述额定交流输入电压Vra的第一预设比例范围及第二预设比例范围之外波动(在本实施例中即为小于所述额定交流输入电压Vra的80％或大于所述额定交流输入电压Vra的120％)，则关断所述整流模块中的功率开关管，即系统中的控制模块不输出PWM驱动信号，并输出故障信号。此时，逆变侧可降载运行或者软停机。所述故障信号包括但不限于欠压保护信号，过压保护信号，在此不一一赘述。Specifically, if the actual AC input voltage Vab fluctuates outside the first preset ratio range and the second preset ratio range of the rated AC input voltage Vra (in this embodiment, it is less than the rated AC input voltage Vra). If the voltage Vra is 80% or greater than 120% of the rated AC input voltage Vra), the power switch in the rectifier module is turned off, that is, the control module in the system does not output a PWM drive signal and outputs a fault signal. At this time, the inverter side can run at reduced load or soft stop. The fault signal includes, but is not limited to, an undervoltage protection signal and an overvoltage protection signal, which will not be repeated here.
需要说明的是，各预设比例范围可根据实际需要进行设定，所述第二预设比例范围的最小值大于等于所述第一预设比例范围的最大值，在此不一一赘述。It should be noted that each preset ratio range can be set according to actual needs, and the minimum value of the second preset ratio range is greater than or equal to the maximum value of the first preset ratio range, which will not be repeated here.
2、当所述电机运行在所述额定转速以上时，控制整流模块升高直流母线电压Vbus，使得电机推迟进入弱磁区。2. When the motor runs above the rated speed, the rectifier module is controlled to increase the DC bus voltage Vbus, so that the motor delays entering the field weakening zone.
具体地，首先计算所述电机转速与所述直流母线电压Vbus的关系曲线。Specifically, firstly, the relationship curve between the rotation speed of the motor and the DC bus voltage Vbus is calculated.
更具体地，所述关系曲线以所述电机转速作为横坐标，以所述直流母线电压作为纵坐标。更具体地，以电机额定转速及高于额定交流输入电压Vra峰值的预设值作为横纵坐标确定所述关系曲线的第一端点。在本实施例中，所述电机转速对应为所述电机额定转速，所述直流母线电压Vbus对应为高于额定交流输入电压Vra峰值的预设值，以此确定所述关系曲线的第一端点。作为示例，所述电机额定转速为6000rpm，所述预设值(高于额定交流输入电压Vra 的峰值)设定为380V(额定交流输入电压)*1.414(峰值)*1.01＝543V。More specifically, the relationship curve uses the motor speed as the abscissa and the DC bus voltage as the ordinate. More specifically, the first end point of the relationship curve is determined by using the rated speed of the motor and the preset value higher than the peak value of the rated AC input voltage Vra as the abscissa and ordinate. In this embodiment, the motor speed corresponds to the rated speed of the motor, and the DC bus voltage Vbus corresponds to a preset value higher than the peak value of the rated AC input voltage Vra, so as to determine the first end of the relationship curve point. As an example, the rated speed of the motor is 6000 rpm, and the preset value (higher than the peak value of the rated AC input voltage Vra) is set to 380V (rated AC input voltage)*1.414 (peak value)*1.01=543V.
需要说明的是，在本实施例中，所述预设值设定为所述额定交流输入电压Vra峰值的101％，在实际使用中，可根据需要设定所述直流母线电压Vbus与所述额定交流输入电压Vra峰值的比例关系，作为示例可设定为100％～105％(不包括端点100％，包括端点105％)，不以本实施例为限。It should be noted that in this embodiment, the preset value is set to 101% of the peak value of the rated AC input voltage Vra. In actual use, the DC bus voltage Vbus and the The proportional relationship of the peak value of the rated AC input voltage Vra, as an example, can be set to 100%-105% (not including the terminal 100%, including the terminal 105%), and is not limited to this embodiment.
更具体地，以所述直流母线电压的最大值Vbus_max及所述直流母线电压的最大值Vbus_max对应的电机转速确定所述关系曲线的第二端点。在本实施例中，所述直流母线电压Vbus对应为所述直流母线电压的最大值Vbus_max，所述电机转速对应为所述直流母线电压的最大值Vbus_max时的电机转速，以此确定所述关系曲线的第二端点。所述直流母线电压的最大值Vbus_max满足如下关系式：Vbus_max＝Vce*k，其中，Vce为功率开关管最大额定值，k为安全系数，且k＝0.6-0.8。作为示例，所述直流母线电压的最大值Vbus_max设定为1200(功率开关管最大额定值，即功率开关管耐压值)*0.6(安全系数)＝720V，对应电机转速为720V(直流母线电压最大值)÷60V/krpm(电机反电势常数)＝12000rpm。More specifically, the second end of the relationship curve is determined by the motor speed corresponding to the maximum value Vbus_max of the DC bus voltage and the maximum value Vbus_max of the DC bus voltage. In this embodiment, the DC bus voltage Vbus corresponds to the maximum value of the DC bus voltage Vbus_max, and the motor speed corresponds to the motor speed when the maximum value of the DC bus voltage Vbus_max, so as to determine the relationship The second end of the curve. The maximum value of the DC bus voltage Vbus_max satisfies the following relationship: Vbus_max=Vce*k, where Vce is the maximum rated value of the power switch tube, k is the safety factor, and k=0.6-0.8. As an example, the maximum value of the DC bus voltage Vbus_max is set to 1200 (the maximum rated value of the power switch tube, that is, the withstand voltage value of the power switch tube) * 0.6 (safety factor) = 720V, and the corresponding motor speed is 720V (DC bus voltage Maximum value) ÷ 60V/krpm (motor back electromotive force constant) = 12000rpm.
需要说明的是，所述关系曲线的横纵坐标可互换，不以本实施例为限。It should be noted that the abscissa and ordinate of the relationship curve can be interchanged, which is not limited to this embodiment.
具体地，再连接所述第一端点及所述第二端点以确定所述关系曲线。Specifically, the first end point and the second end point are then connected to determine the relationship curve.
更具体地，将所述第一端点与所述第二端点连接，由此得到的直线即为所述关系曲线。More specifically, the first end point is connected to the second end point, and the straight line thus obtained is the relationship curve.
作为本发明的另一种实现方式，进一步地，参考实际测试数据，增加所述关系曲线的端点，各端点依次连接后得到的曲线即为所述关系曲线。增加的端点数量可根据需要设定，在此不一一赘述。As another implementation of the present invention, further, referring to actual test data, the endpoints of the relationship curve are added, and the curve obtained after each endpoint is connected in sequence is the relationship curve. The number of added endpoints can be set according to needs, and will not be repeated here.
具体地，根据电机预设转速或者检测电机实际转速(通过闭环控制，电机实际转速总是跟踪电机预设转速)，从所述关系曲线上得到所述电机转速对应的所述直流母线电压Vbus。Specifically, the DC bus voltage Vbus corresponding to the motor speed is obtained from the relationship curve according to the preset speed of the motor or the actual speed of the detected motor (through closed-loop control, the actual speed of the motor always tracks the preset speed of the motor).
具体地，最后判断所述直流母线电压Vbus是否符合要求，即若所述直流母线电压Vbus低于所述实际交流输入电压Vab的峰值，则将所述直流母线电压Vbus调整为高于实际交流输入电压Vab的峰值；否则不调整，以所述关系曲线上得到的值为准；以此确定所述直流母线电压Vbus。Specifically, it is finally determined whether the DC bus voltage Vbus meets the requirements, that is, if the DC bus voltage Vbus is lower than the peak value of the actual AC input voltage Vab, the DC bus voltage Vbus is adjusted to be higher than the actual AC input The peak value of the voltage Vab; otherwise, it will not be adjusted, and the value obtained on the relationship curve shall prevail; this will determine the DC bus voltage Vbus.
3、作为本发明的另一种实现方式，当所述直流母线电压Vbus达到直流母线电压最大值Vbus_max时，若此时希望继续提高电机转速，则只能通过改变励磁电流，使电机磁通减弱，即电机进入弱磁升速模式。3. As another implementation of the present invention, when the DC bus voltage Vbus reaches the maximum value of the DC bus voltage Vbus_max, if you want to continue to increase the motor speed at this time, you can only change the excitation current to weaken the motor flux , That is, the motor enters the field weakening speed-up mode.
本实施例采用有源整流模块，大大减小了电网的低次谐波；在额定转速以下时，考虑了电网的影响，通过控制直流母线电压随着电网变化，提高了逆变模块的效率；在额定转速以 上时，通过控制整流模块升高直流母线电压，使得电机推迟进入弱磁区，提高了电机的效率；综合永磁同步电机全速度范围工况及交流输入电压波动，使得变频调速系统处于最高效率的工作模式。This embodiment adopts an active rectifier module, which greatly reduces the low-order harmonics of the power grid; when the speed is below the rated speed, the influence of the power grid is considered, and the efficiency of the inverter module is improved by controlling the DC bus voltage to change with the power grid; When the rated speed is above the rated speed, the rectifier module is controlled to increase the DC bus voltage, which delays the entry of the motor into the field weakening zone and improves the efficiency of the motor; comprehensive permanent magnet synchronous motor full speed range working conditions and AC input voltage fluctuations make the variable frequency speed regulation system In the most efficient working mode.
实施例二Example two
本实施例提供一种压缩机变频调速系统中直流母线电压的控制方法，与实施例一的不同之处在于，当所述实际交流输入电压Vab在所述额定交流输入电压Vra的第二预设比例范围内波动时，根据不同子区间进行不同的处理。This embodiment provides a method for controlling the DC bus voltage in a compressor variable frequency speed regulation system. The difference from the first embodiment is that when the actual AC input voltage Vab is at the second preset value of the rated AC input voltage Vra When fluctuating within the range of the ratio, different processing is performed according to different sub-intervals.
具体地，当所述电机运行在所述额定转速以下时：Specifically, when the motor runs below the rated speed:
若实际交流输入电压Vab在额定交流输入电压Vra的80％～100％之间波动，则控制整流模块以将所述直流母线电压Vbus设置为高于所述额定交流输入电压Vra的峰值，且所述直流母线电压Vbus保持恒定(固定值)。If the actual AC input voltage Vab fluctuates between 80% and 100% of the rated AC input voltage Vra, the rectifier module is controlled to set the DC bus voltage Vbus to be higher than the peak value of the rated AC input voltage Vra, and The DC bus voltage Vbus remains constant (fixed value).
若所述实际交流输入电压Vab在所述额定交流输入电压Vra的第二预设比例范围的第一子区间(在本实施例中，所述第一子区间设定为100％～110％，在实际使用中，可根据需要设定所述第一子区间的范围，不以本实施例为限)内波动，则控制所述整流模块以将所述直流母线电压Vbus设置为高于所述实际交流输入电压Vab的峰值，且所述直流母线电压Vbus随着所述实际交流输入电压Vab的变化而变化。If the actual AC input voltage Vab is in the first sub-interval of the second preset ratio range of the rated AC input voltage Vra (in this embodiment, the first sub-interval is set to 100%-110%, In actual use, the range of the first sub-interval can be set according to needs, and this embodiment is not limited to) internal fluctuations, then the rectifier module is controlled to set the DC bus voltage Vbus higher than the The peak value of the actual AC input voltage Vab, and the DC bus voltage Vbus changes with the change of the actual AC input voltage Vab.
若所述实际交流输入电压Vab在所述额定交流输入电压Vra的第二预设比例范围的第二子区间(在本实施例中，所述第一子区间设定为110％～120％，在实际使用中，可根据需要设定所述第二子区间的范围，不以本实施例为限)内波动时，关断整流模块中的功率开关管，即系统中的控制模块不输出PWM驱动信号，进入不控整流模式。由此可带来两个好处：一，不控整流模式可以减小整流模块的开关损耗；二、此时，当电机负载变大时，直流母线电压Vbus虽然会变低，但也足够高到可以满足电机的端电压要求，因此逆变侧的调制度无需维持太高，则整流模块及逆变模块的导通损耗会减小。If the actual AC input voltage Vab is in the second sub-interval of the second preset ratio range of the rated AC input voltage Vra (in this embodiment, the first sub-interval is set to 110%-120%, In actual use, the range of the second sub-interval can be set according to needs, and the power switch tube in the rectifier module is turned off when the internal fluctuation is not limited to this embodiment, that is, the control module in the system does not output PWM The drive signal enters the uncontrolled rectification mode. This can bring two benefits: First, the uncontrolled rectification mode can reduce the switching loss of the rectifier module; Second, when the motor load becomes larger, the DC bus voltage Vbus will become low, but it is high enough. It can meet the terminal voltage requirements of the motor, so the modulation degree of the inverter side does not need to be maintained too high, and the conduction loss of the rectifier module and the inverter module will be reduced.
若所述实际交流输入电压Vab小于所述额定交流输入电压Vra的80％或大于额定交流输入电压Vra的120％，则关断所述整流模块中的功率开关管，并输出故障信号。If the actual AC input voltage Vab is less than 80% of the rated AC input voltage Vra or greater than 120% of the rated AC input voltage Vra, the power switch tube in the rectifier module is turned off and a fault signal is output.
需要说明的是，所述电机运行在所述额定转速以上及所述直流母线电压达到直流母线电压最大值时的工作方法、原理与实施例一相同，在此不一一赘述。It should be noted that the working method and principle when the motor runs above the rated speed and the DC bus voltage reaches the maximum value of the DC bus voltage are the same as those in the first embodiment, and will not be repeated here.
实施例三Example three
如图3所示，本实施例提供一种压缩机变频调速系统1，所述压缩机变频调速系统1包括：As shown in FIG. 3, this embodiment provides a compressor frequency conversion speed regulation system 1, and the compressor frequency conversion speed regulation system 1 includes:
整流模块11，逆变模块12，电机13及控制模块14。Rectifier module 11, inverter module 12, motor 13 and control module 14.
如图3所示，所述整流模块11接收交流输入电压，并将所述交流输入电压转化为直流母线电压Vbus。As shown in FIG. 3, the rectifier module 11 receives an AC input voltage and converts the AC input voltage into a DC bus voltage Vbus.
具体地，在本实施例中，所述整流模块11为有源整流模块中的VIENNA整流模块，VIENNA拓补的各种变形均适用于本发明的所述整流模块11。作为示例，所述整流模块11包括六个二极管、三个电感、六个功率开关管及两组电容(两组电容可以是单个电容或多个电容串并联的组合)，且上下两组电容的容值相同。各二极管两两同向串联后并联，即：第一二极管D1的阴极连接所述直流母线电压的正极Vbus+，阳极连接第二二极管D2的阴极；所述第二二极管D2的阳极连接所述直流母线电压的负极Vbus-；第三二极管D3的阴极连接所述直流母线电压的正极Vbus+，阳极连接第四二极管D4的阴极；所述第四二极管D4的阳极连接所述直流母线电压的负极Vbus-；第五二极管D5的阴极连接所述直流母线电压的正极Vbus+，阳极连接第六二极管D6的阴极；所述第六二极管D6的阳极连接所述直流母线电压V的负极Vbus-。所述第一二极管D1与所述第二二极管D2的连接节点连接所述交流输入电压的第一相L1，所述第三二极管D3与所述第四二极管D4的连接节点连接所述交流输入电压的第二相L2，所述第五二极管D5与所述第六二极管D6的连接节点连接所述交流输入电压的第三相L3。所述交流输入电压的各相分别通过一电感(第一电感L11、第二电感L12及第三电感L13)后输入。第一组电容C1及第二组电容C2串联后连接于所述直流母线电压的正极Vbus+与负极Vbus-之间。各功率开关管两两反向串联后分别连接于各组串联二极管的连接节点与两组电容的连接节点之间，即：第一功率开关管Q11的集电极连接所述第一二极管D1与所述第二二极管D2的连接节点，发射极连接第二功率开关管Q12的发射极；所述第二功率开关管Q12的集电极连接所述第一组电容C1与所述第二组电容C2的连接节点；第三功率开关管Q13的集电极连接所述第三二极管D3与所述第四二极管D4的连接节点，发射极连接第四功率开关管Q14的发射极；所述第四功率开关管Q14的集电极连接所述第一组电容C1与所述第二组电容C2的连接节点；第五功率开关管Q15的集电极连接所述第五二极管D5与所述第六二极管D6的连接节点，发射极连接第六功率开关管Q16的发射极；所述第六功率开关管Q16的集电极连接所述第一组电容C1与所述第二组电容C2的连接节点。所述整流模块11中各功率开关管分别连接一控制信号。Specifically, in this embodiment, the rectifier module 11 is a VIENNA rectifier module in an active rectifier module, and various variations of VIENNA topology are applicable to the rectifier module 11 of the present invention. As an example, the rectifier module 11 includes six diodes, three inductors, six power switch tubes, and two sets of capacitors (the two sets of capacitors can be a single capacitor or a combination of multiple capacitors in series and parallel), and the upper and lower two sets of capacitors The capacitance value is the same. Each diode is connected in parallel in series in the same direction, that is: the cathode of the first diode D1 is connected to the anode Vbus+ of the DC bus voltage, and the anode is connected to the cathode of the second diode D2; The anode is connected to the cathode Vbus- of the DC bus voltage; the cathode of the third diode D3 is connected to the anode Vbus+ of the DC bus voltage, and the anode is connected to the cathode of the fourth diode D4; The anode is connected to the negative pole Vbus- of the DC bus voltage; the cathode of the fifth diode D5 is connected to the positive pole Vbus+ of the DC bus voltage, and the anode is connected to the cathode of the sixth diode D6; The anode is connected to the cathode Vbus- of the DC bus voltage V. The connection node of the first diode D1 and the second diode D2 is connected to the first phase L1 of the AC input voltage, and the third diode D3 and the fourth diode D4 are connected to each other. The connection node is connected to the second phase L2 of the AC input voltage, and the connection node of the fifth diode D5 and the sixth diode D6 is connected to the third phase L3 of the AC input voltage. Each phase of the AC input voltage is input through an inductor (the first inductor L11, the second inductor L12, and the third inductor L13) respectively. The first group of capacitors C1 and the second group of capacitors C2 are connected in series and connected between the positive pole Vbus+ and the negative pole Vbus- of the DC bus voltage. Each power switch tube is connected in reverse series in pairs, respectively, between the connection node of each group of series diodes and the connection node of the two sets of capacitors, that is: the collector of the first power switch tube Q11 is connected to the first diode D1 With the connection node of the second diode D2, the emitter is connected to the emitter of the second power switch Q12; the collector of the second power switch Q12 is connected to the first group of capacitors C1 and the second The connection node of the group capacitor C2; the collector of the third power switch Q13 is connected to the connection node of the third diode D3 and the fourth diode D4, and the emitter is connected to the emitter of the fourth power switch Q14 The collector of the fourth power switch tube Q14 is connected to the connection node of the first group of capacitors C1 and the second group of capacitors C2; the collector of the fifth power switch tube Q15 is connected to the fifth diode D5 With the connection node of the sixth diode D6, the emitter is connected to the emitter of the sixth power switch Q16; the collector of the sixth power switch Q16 is connected to the first group of capacitors C1 and the second The connection node of the group capacitor C2. Each power switch tube in the rectifier module 11 is respectively connected to a control signal.
需要说明的是，本实施例电网电源为三相四线制(三根火线一根地线)，如果是三相五线制(三根火线一根中线一根地线)，则中线连接两组电容的连接节点。It should be noted that the power grid in this embodiment is a three-phase four-wire system (three live wires and one ground wire). If it is a three-phase five-wire system (three live wires, one neutral wire and one ground wire), the neutral wire is connected to two sets of capacitors. Connection node.
需要说明的是，在本实施例中，各功率开关管采用绝缘栅双极型晶体管，在实际使用中 可根据需要设定各功率开关管的类型。所述整流模块11可以是任意可控的有源整流模块；也可以包括无源整流单元及升压单元，所述升压单元连接于所述无源整流单元的输出端；以此实现可控整流，不以本实施例为限。It should be noted that in this embodiment, each power switch tube adopts an insulated gate bipolar transistor, and the type of each power switch tube can be set according to needs in actual use. The rectifier module 11 can be any controllable active rectifier module; it can also include a passive rectifier unit and a booster unit, the booster unit is connected to the output end of the passive rectifier unit; in order to achieve controllability Rectification is not limited to this embodiment.
如图3所示，所述逆变模块12连接所述整流模块11的输出端，将所述直流母线电压Vbus转换为电机驱动电压。As shown in FIG. 3, the inverter module 12 is connected to the output terminal of the rectifier module 11, and converts the DC bus voltage Vbus into a motor drive voltage.
具体地，在本实施例中，所述逆变模块12六个功率开关管，构成三相逆变桥，其中，第七功率开关管Q21及第八功率开关管Q22串联于所述直流母线电压的正极Vbus+和所述直流母线电压的负极Vbus-之间(所述第七功率开关管Q21的集电极连接所述直流母线电压的正极Vbus+、发射极连接所述第八功率开关管Q22的集电极，所述第八功率开关管Q22的发射极连接所述直流母线电压的负极Vbus-)；第九功率开关管Q23及第十功率开关管Q24串联于所述直流母线电压的正极Vbus+和所述直流母线电压的负极Vbus-之间(连接端口与所述第七功率开关管Q21及所述第八功率开关管Q22相同，在此不一一赘述)；第十一功率开关管Q25及第十二功率开关管Q26串联于所述直流母线电压的正极Vbus+和所述直流母线电压的负极Vbus-之间(连接端口与所述第七功率开关管Q21及所述第八功率开关管Q22相同，在此不一一赘述)；所述逆变模块12中各功率开关管分别连接一控制信号。Specifically, in this embodiment, the six power switch tubes of the inverter module 12 constitute a three-phase inverter bridge, wherein the seventh power switch tube Q21 and the eighth power switch tube Q22 are connected in series to the DC bus voltage Between the positive pole Vbus+ of the DC bus voltage and the negative pole Vbus- of the DC bus voltage (the collector of the seventh power switch tube Q21 is connected to the positive pole Vbus+ of the DC bus voltage, and the emitter is connected to the collector of the eighth power switch tube Q22. The emitter of the eighth power switch tube Q22 is connected to the negative pole Vbus-) of the DC bus voltage; the ninth power switch tube Q23 and the tenth power switch tube Q24 are connected in series to the positive pole Vbus+ of the DC bus voltage and the Between the negative pole Vbus- of the DC bus voltage (the connection port is the same as the seventh power switch Q21 and the eighth power switch Q22, and will not be repeated here); the eleventh power switch Q25 and the first Twelve power switch tubes Q26 are connected in series between the positive pole Vbus+ of the DC bus voltage and the negative pole Vbus- of the DC bus voltage (the connection port is the same as the seventh power switch tube Q21 and the eighth power switch tube Q22 , Which will not be repeated here); each power switch tube in the inverter module 12 is connected to a control signal.
需要说明的是，在本实施例中，所述逆变模块12中各功率开关管为绝缘栅双极型晶体管，在实际使用中可根据需要设定各功率开关管的类型。所述逆变模块12可根据需要选择任意一种结构，不以本实施例为限。It should be noted that, in this embodiment, each power switch tube in the inverter module 12 is an insulated gate bipolar transistor, and the type of each power switch tube can be set as required in actual use. The inverter module 12 can choose any structure according to needs, and is not limited to this embodiment.
如图3所示，所述电机13连接于所述逆变模块12的输出端，受所述电机驱动电压的驱动运转。As shown in FIG. 3, the motor 13 is connected to the output terminal of the inverter module 12, and is driven by the motor driving voltage.
具体地，在本实施例中，所述电机13为永磁同步电机，当电机的三相定子绕组通入三相交流电后，将产生一个旋转磁场，该旋转磁场带动转子同步旋转。在其他实施例中，所述电机13也可以为交流异步电机等其他三相电机，在此不一一赘述。Specifically, in this embodiment, the motor 13 is a permanent magnet synchronous motor. When a three-phase alternating current is applied to the three-phase stator windings of the motor, a rotating magnetic field will be generated, and the rotating magnetic field will drive the rotor to rotate synchronously. In other embodiments, the motor 13 may also be other three-phase motors such as an AC asynchronous motor, which will not be repeated here.
如图3所示，所述控制模块14连接所述电机13、所述整流模块11及所述逆变模块12，产生所述整流模块11及所述逆变模块12的控制信号。As shown in FIG. 3, the control module 14 is connected to the motor 13, the rectifier module 11 and the inverter module 12 to generate control signals of the rectifier module 11 and the inverter module 12.
具体地，在本实施例中，所述控制模块14采集交流输入电压及所述电机13上的信号，并控制所述整流模块11、所述逆变模块12以执行实施例一或实施例二的压缩机变频调速系统中直流母线电压的控制方法实现所述电机13的调速，工作原理参见实施例一及实施例二，在此不一一赘述。Specifically, in this embodiment, the control module 14 collects the AC input voltage and the signal on the motor 13, and controls the rectifier module 11 and the inverter module 12 to implement the first embodiment or the second embodiment. The control method of the DC bus voltage in the compressor frequency conversion speed regulation system of the compressor realizes the speed regulation of the motor 13. For the working principle, please refer to the first embodiment and the second embodiment, which will not be repeated here.
本实施例的压缩机变频调速系统大大减小了电网的低次谐波、提高了系统效率，压缩机 变频调速系统(包括被控电机)始终处于最高效率的工作模式，适于产业应用。The compressor frequency conversion speed regulation system of this embodiment greatly reduces the low-order harmonics of the power grid and improves the system efficiency. The compressor frequency conversion speed regulation system (including the controlled motor) is always in the highest efficiency working mode, which is suitable for industrial applications .
综上所述，本发明提供一种压缩机变频调速系统及直流母线电压的控制方法，包括：整流模块，接收交流输入电压，并将所述交流输入电压转化为直流母线电压；逆变模块，连接所述整流模块的输出端，将所述直流母线电压转换为电机驱动电压；电机，连接于所述逆变模块的输出端，受所述电机驱动电压的驱动运转；控制模块，连接所述电机、所述整流模块及所述逆变模块，用于产生所述整流模块及所述逆变模块的控制信号；当电机运行在额定转速以下时，根据交流输入电压输出直流母线电压；当所述电机运行在所述额定转速以上时，根据所述交流输入电压及所述电机的转速输出所述直流母线电压。本发明的压缩机变频调速系统的前级采用有源整流模块，大大减小了电网的低次谐波；在额定转速以下时，考虑了电网的影响，通过控制直流母线电压随着电网变化，提高了逆变模块的效率；在额定转速以上时，通过控制整流模块升高直流母线电压，使得电机推迟进入弱磁区，提高了电机的效率；综合永磁同步电机全速度范围工况及交流输入电压波动，使得变频调速系统处于最高效率的工作模式。所以，本发明有效克服了现有技术中的种种缺点而具高度产业利用价值。In summary, the present invention provides a compressor frequency conversion speed regulation system and a DC bus voltage control method, including: a rectifier module, which receives an AC input voltage and converts the AC input voltage into a DC bus voltage; an inverter module , Connected to the output terminal of the rectifier module to convert the DC bus voltage into a motor drive voltage; a motor, connected to the output terminal of the inverter module, and operated by the motor drive voltage; a control module, connected to the The motor, the rectifier module, and the inverter module are used to generate control signals of the rectifier module and the inverter module; when the motor runs below the rated speed, the DC bus voltage is output according to the AC input voltage; When the motor runs above the rated speed, the DC bus voltage is output according to the AC input voltage and the speed of the motor. The front stage of the compressor variable frequency speed regulation system of the present invention adopts an active rectifier module, which greatly reduces the low-order harmonics of the power grid; when the speed is below the rated speed, the influence of the power grid is considered, and the DC bus voltage is controlled to change with the power grid. , Improve the efficiency of the inverter module; when the rated speed is higher than the rated speed, the rectifier module is controlled to increase the DC bus voltage, which delays the entry of the motor into the field weakening zone and improves the efficiency of the motor; comprehensive permanent magnet synchronous motor full speed range working conditions and AC The input voltage fluctuates, so that the variable frequency speed regulation system is in the most efficient working mode. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial value.
上述实施例仅例示性说明本发明的原理及其功效，而非用于限制本发明。任何熟悉此技术的人士皆可在不违背本发明的精神及范畴下，对上述实施例进行修饰或改变。因此，举凡所属技术领域中具有通常知识者在未脱离本发明所揭示的精神与技术思想下所完成的一切等效修饰或改变，仍应由本发明的权利要求所涵盖。The above-mentioned embodiments only exemplarily illustrate the principles and effects of the present invention, and are not used to limit the present invention. Anyone familiar with this technology can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims (11)

  1. 一种压缩机变频调速系统中直流母线电压的控制方法，其特征在于，所述压缩机变频调速系统中直流母线电压的控制方法至少包括：A method for controlling the DC bus voltage in a compressor variable frequency speed regulation system is characterized in that the method for controlling the DC bus voltage in the compressor variable frequency speed regulation system at least includes:
    当电机运行在额定转速以下时，根据交流输入电压输出直流母线电压；When the motor is running below the rated speed, the DC bus voltage is output according to the AC input voltage;
    当所述电机运行在所述额定转速以上时，根据所述交流输入电压及电机转速输出所述直流母线电压。When the motor runs above the rated speed, the DC bus voltage is output according to the AC input voltage and the motor speed.
  2. 根据权利要求1所述的压缩机变频调速系统中直流母线电压的控制方法，其特征在于：当所述电机运行在所述额定转速以下时，The method for controlling the DC bus voltage in a compressor variable frequency speed regulation system according to claim 1, characterized in that: when the motor is running below the rated speed,
    若实际交流输入电压在额定交流输入电压的第一预设比例范围内波动，则所述直流母线电压设置为高于所述额定交流输入电压峰值的固定值；If the actual AC input voltage fluctuates within the first preset ratio range of the rated AC input voltage, the DC bus voltage is set to a fixed value higher than the peak value of the rated AC input voltage;
    若所述实际交流输入电压在所述额定交流输入电压的第二预设比例范围内波动，则所述直流母线电压设置为高于所述实际交流输入电压的峰值，所述直流母线电压随着所述实际交流输入电压的变化而变化；If the actual AC input voltage fluctuates within the second preset ratio range of the rated AC input voltage, the DC bus voltage is set to be higher than the peak value of the actual AC input voltage, and the DC bus voltage follows The actual AC input voltage changes;
    若所述实际交流输入电压在所述额定交流输入电压的第一预设比例范围及第二预设比例范围之外波动，则关断整流模块中的功率开关管，并输出故障信号；If the actual AC input voltage fluctuates outside the first preset ratio range and the second preset ratio range of the rated AC input voltage, turn off the power switch tube in the rectifier module and output a fault signal;
    其中，所述第二预设比例范围的最小值大于等于所述第一预设比例范围的最大值。Wherein, the minimum value of the second preset ratio range is greater than or equal to the maximum value of the first preset ratio range.
  3. 根据权利要求2所述的压缩机变频调速系统中直流母线电压的控制方法，其特征在于：当所述实际交流输入电压在所述额定交流输入电压的第二预设比例范围的第一子区间内波动时，所述直流母线电压设置为高于所述实际交流输入电压的峰值，所述直流母线电压随着所述实际交流输入电压的变化而变化；The method for controlling the DC bus voltage in a compressor variable frequency speed regulation system according to claim 2, wherein: when the actual AC input voltage is within the first sub-range of the second preset ratio range of the rated AC input voltage When fluctuates within the interval, the DC bus voltage is set to be higher than the peak value of the actual AC input voltage, and the DC bus voltage changes with changes in the actual AC input voltage;
    当所述实际交流输入电压在所述额定交流输入电压的第二预设比例范围的第二子区间内波动时，关断整流模块中的功率开关管，进入不控整流模式。When the actual AC input voltage fluctuates within the second sub-interval of the second preset ratio range of the rated AC input voltage, the power switch tube in the rectifier module is turned off, and the uncontrolled rectification mode is entered.
  4. 根据权利要求1～3任意一项所述的压缩机变频调速系统中直流母线电压的控制方法，其特征在于：当所述电机运行在所述额定转速以上时，The method for controlling DC bus voltage in a compressor variable frequency speed regulation system according to any one of claims 1 to 3, characterized in that: when the motor is running above the rated speed,
    计算所述电机转速与所述直流母线电压的关系曲线；Calculating the relationship curve between the motor speed and the DC bus voltage;
    从所述关系曲线上得到所述电机转速对应的所述直流母线电压；Obtaining the DC bus voltage corresponding to the motor speed from the relationship curve;
    若所述直流母线电压低于实际交流输入电压的峰值，则将所述直流母线电压调整为高于实际交流输入电压的峰值。If the DC bus voltage is lower than the peak value of the actual AC input voltage, the DC bus voltage is adjusted to be higher than the peak value of the actual AC input voltage.
  5. 根据权利要求4所述的压缩机变频调速系统中直流母线电压的控制方法，其特征在于：计算所述电机转速与所述直流母线电压的关系曲线的方法包括：The method for controlling the DC bus voltage in a compressor variable frequency speed regulation system according to claim 4, wherein the method of calculating the relationship curve between the motor speed and the DC bus voltage comprises:
    以电机额定转速及高于所述额定交流输入电压峰值的预设值作为横纵坐标确定所述关系曲线的第一端点；Determine the first end point of the relationship curve by using the rated speed of the motor and a preset value higher than the peak value of the rated AC input voltage as the abscissa and ordinate;
    以所述直流母线电压的最大值及所述直流母线电压的最大值对应的电机转速确定所述关系曲线的第二端点；Determining the second end point of the relationship curve by using the maximum value of the DC bus voltage and the motor speed corresponding to the maximum value of the DC bus voltage;
    连接所述第一端点及所述第二端点确定所述关系曲线。The relationship curve is determined by connecting the first end point and the second end point.
  6. 根据权利要求5所述的压缩机变频调速系统中直流母线电压的控制方法，其特征在于：计算所述电机转速与所述直流母线电压的关系曲线的方法还包括：基于实际测试数据增加所述关系曲线的端点，各端点依次连接后确定所述关系曲线。The method for controlling the DC bus voltage in the compressor variable frequency speed regulation system according to claim 5, characterized in that: the method of calculating the relationship curve between the motor speed and the DC bus voltage further comprises: increasing the voltage based on actual test data. The endpoints of the relationship curve are connected in sequence to determine the relationship curve.
  7. 根据权利要求1所述的压缩机变频调速系统中直流母线电压的控制方法，其特征在于：当所述直流母线电压达到直流母线电压最大值时，进入弱磁升速模式。The method for controlling the DC bus voltage in the compressor variable frequency speed regulation system according to claim 1, characterized in that: when the DC bus voltage reaches the maximum value of the DC bus voltage, the field weakening speed-up mode is entered.
  8. 一种压缩机变频调速系统，执行如权利要求1～7任意一项所述的压缩机变频调速系统中直流母线电压的控制方法，其特征在，所述压缩机变频调速系统至少包括：A compressor frequency conversion speed regulation system, which implements the DC bus voltage control method in the compressor frequency conversion speed regulation system of any one of claims 1-7, characterized in that the compressor frequency conversion speed regulation system at least includes :
    整流模块，接收交流输入电压，并将所述交流输入电压转化为直流母线电压；A rectifier module, which receives an AC input voltage and converts the AC input voltage into a DC bus voltage;
    逆变模块，连接所述整流模块的输出端，将所述直流母线电压转换为电机驱动电压；An inverter module, connected to the output terminal of the rectifier module, and converts the DC bus voltage into a motor drive voltage;
    电机，连接于所述逆变模块的输出端，受所述电机驱动电压的驱动运转；A motor, connected to the output terminal of the inverter module, and driven by the motor drive voltage to run;
    控制模块，连接所述电机、所述整流模块及所述逆变模块，用于产生所述整流模块及所述逆变模块的控制信号。The control module is connected to the motor, the rectifier module and the inverter module, and is used to generate control signals of the rectifier module and the inverter module.
  9. 根据权利要求8所述的压缩机变频调速系统，其特征在于：所述整流模块为有源整流模块；或所述整流模块包括无源整流单元及升压单元，所述升压单元连接于所述无源整流单元的输出端。The compressor variable frequency speed regulation system according to claim 8, wherein: the rectifier module is an active rectifier module; or the rectifier module includes a passive rectifier unit and a booster unit, and the booster unit is connected to The output terminal of the passive rectification unit.
  10. 根据权利要求9所述的压缩机变频调速系统，其特征在于：所述有源整流模块为VIENNA整流模块。The compressor variable frequency speed regulation system according to claim 9, wherein the active rectifier module is a VIENNA rectifier module.
  11. 根据权利要求10所述的压缩机变频调速系统，其特征在于：所述VIENNA整流模块， 包括六个二极管、三个电感、六个功率开关管及两组电容；各二极管两两同向串联后并联，第一组串联二极管的连接节点经由第一电感连接所述交流输入电压的第一相，第二组串联二极管的连接节点经由第二电感连接所述交流输入电压的第二相，第三组串联二极管的连接节点经由第三电感连接所述交流输入电压的第三相；两组电容串联后与各组串联二极管并联；各功率开关管两两反向串联后分别连接于各组串联二极管的连接节点与两组电容的连接节点之间。The compressor variable frequency speed regulation system of claim 10, wherein the VIENNA rectifier module includes six diodes, three inductors, six power switch tubes, and two sets of capacitors; each diode is connected in series in two in the same direction. After connecting in parallel, the connection node of the first group of series diodes is connected to the first phase of the AC input voltage via a first inductor, and the connection node of the second group of series diodes is connected to the second phase of the AC input voltage via a second inductor. The connection nodes of the three groups of series diodes are connected to the third phase of the AC input voltage through the third inductor; the two groups of capacitors are connected in series and connected in parallel with each group of series diodes; each power switch tube is connected in reverse series in pairs and connected to each group in series. Between the connection node of the diode and the connection node of the two sets of capacitors.
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