CN108023473A - Pfc circuit, electric machine control system and transducer air conditioning - Google Patents

Pfc circuit, electric machine control system and transducer air conditioning Download PDF

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Publication number
CN108023473A
CN108023473A CN201810088105.5A CN201810088105A CN108023473A CN 108023473 A CN108023473 A CN 108023473A CN 201810088105 A CN201810088105 A CN 201810088105A CN 108023473 A CN108023473 A CN 108023473A
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China
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value
current
voltage
motor
signal
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CN201810088105.5A
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CN108023473B (en
Inventor
霍军亚
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GD Midea Air Conditioning Equipment Co Ltd
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Guangdong Midea Refrigeration Equipment Co Ltd
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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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
    • H02M1/4208—Arrangements for improving power factor of AC input
    • H02M1/4225—Arrangements for improving power factor of AC input using a non-isolated boost converter
    • 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
    • H02P23/00—Arrangements or methods for the control of AC motors characterised by a control method other than vector control
    • H02P23/26—Power factor control [PFC]
    • 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
    • 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
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

The present invention provides a kind of pfc circuit, electric machine control system and transducer air conditioning, electric machine control system is by including reactor, rectification part, current detecting part, filter circuit, alternating voltage sampling unit, DC voltage sampling unit and calculation control unit composition, and rectification part including four rectifier diodes switch element that the rectification unit in parallel connected again and two switching tubes are connected two-by-two by being formed in parallel, full-wave rectifying circuit is formed with this, calculation control unit includes PFC calculation control units, by the DC bus-bar voltage set-point for obtaining motor operation, and according to AC-input voltage value, d-c bus voltage value, the switching tube work of DC bus current value and DC bus-bar voltage set-point generation PFC duty cycle of switching signal driving rectification part, to carry out Active PFC to the alternating current of input.The relatively existing pfc circuit of the pfc circuit of the embodiment of the present invention can effectively improve efficiency, reduce common mode noise, and the reliability of whole electric machine control system is improved with this.

Description

PFC circuit, motor control system and variable frequency air conditioner
Technical Field
The invention relates to the technical field of variable frequency air conditioners, in particular to a PFC circuit, a motor control system and a variable frequency air conditioner.
Background
In order to meet the energy-saving requirement of household appliances, the variable frequency air conditioner is rapidly developed, and the active power factor correction is widely applied to an electric control part of the variable frequency air conditioner. At present, most of power factor correction parts of variable frequency air conditioners electrically control adopt a Boost type circuit, current flows through a rectifier bridge and then is supplied to a motor inverter through an inductor and a diode, and the type of electric control has the defect of low AC-DC (alternating current-direct current) conversion efficiency; or, a bridge-less PFC (power factor correction) circuit has appeared, but this bridge-less PFC circuit has a problem of large common mode noise although the AC-DC conversion efficiency is improved to some extent.
The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.
Disclosure of Invention
The invention mainly aims to provide a PFC circuit, a motor control system and a variable frequency air conditioner, and aims to solve the problems of low conversion efficiency or large common mode noise in the conventional PFC circuit.
In order to achieve the above object, the present invention provides a PFC circuit including a reactor, a rectifying unit, a current detecting unit, a filter circuit, an ac voltage sampling unit, a dc voltage sampling unit, and an arithmetic control unit; the reactor is connected with the input end of the alternating current power supply, and the reactor and the rectifying part are connected in series in the alternating current power supply loop; the output end of the rectifying part is connected with a direct current bus, and the filter circuit is connected with the rectifying part through the direct current bus; the current detection part is connected in series with the direct current bus;
the rectifying part comprises a first diode, a second diode, a third diode, a fourth diode, a first switching tube and a second switching tube, wherein the first switching tube and the second switching tube are provided with freewheeling diodes, and a common anode after the first diode and the second diode are connected in parallel and a common cathode after the third diode and the fourth diode are connected in parallel are connected with an L line of an alternating current power supply; the public connecting point of the first switch tube and the second switch tube after being connected in series is connected with an N line of an alternating current power supply, one end of the first switch tube and the second switch tube after being connected in series is connected with a public cathode of the first diode and the second diode after being connected in parallel, the other end of the first switch tube and the second switch tube after being connected in series is connected with a public anode of the third diode and the fourth diode after being connected in parallel, and the control ends of the first switch tube and the second switch tube are respectively connected with the operation control part; wherein,
the current detection part is used for detecting the direct current bus current and obtaining a corresponding direct current bus current value; the filter circuit is used for smoothing and filtering the direct current output by the rectifying module to output direct current bus voltage; the alternating current voltage sampling part is used for detecting alternating current input voltage and obtaining a corresponding alternating current input voltage value; the direct-current voltage sampling part is used for detecting the direct-current bus voltage and obtaining a corresponding direct-current bus voltage value;
the operation control part comprises a PFC operation control part, and the PFC operation control part is used for obtaining a direct current bus voltage given value of motor operation, and generating a PFC switch duty ratio signal according to the alternating current input voltage value, the direct current bus current value and the direct current bus voltage given value to drive a switch tube of the rectification part to work so as to correct the power factor of the input alternating current.
Preferably, the current detection unit performs current sampling at an intermediate timing when the first switching tube or the second switching tube is turned off.
Preferably, the motor control system includes a phase current sampling section and an inverter;
the phase current sampling part is used for sampling a phase current signal of the motor and inputting the phase current signal into the motor operation control part;
the input end of the inverter is connected with the direct current bus, and the output end of the inverter is connected with the motor;
the operation control part also comprises a motor operation control part, the motor operation control part is used for calculating and generating a pulse width signal according to the direct current bus voltage value, the phase current signal of the motor and the target rotating speed value of the motor, the operation control part also generates a triangular carrier signal, and generates a PWM control signal to the inverter according to the triangular carrier signal and the pulse width signal so as to drive the motor to operate.
Preferably, the motor arithmetic control unit includes:
the position/speed estimation module is used for estimating the rotor position of the motor to obtain a rotor angle estimation value and a motor speed estimation value of the motor;
the Q-axis given current value calculation module is used for calculating a Q-axis given current value according to the target rotating speed value of the motor and the estimated motor speed value;
the D-axis given current value calculation module is used for calculating a D-axis given current value according to the maximum output voltage of the inverter and the output voltage amplitude of the inverter;
and the current control module is used for calculating the phase current value sampled by the motor according to the Q-axis given current value, the D-axis given current value, the motor speed estimation value, the direct-current bus voltage value and the pulse width signal to generate the pulse width signal, and generating the PWM control signal to the inverter according to the triangular carrier signal and the pulse width signal to drive the motor to run.
Preferably, the D-axis given current value calculation module includes:
the flux weakening controller is used for calculating the maximum output voltage of the inverter and the amplitude of the output voltage of the inverter to obtain an initial value of a given current value of a D axis;
and the amplitude limiting unit is used for carrying out amplitude limiting processing on the D-axis given current value initial value so as to obtain the D-axis given current value.
Preferably, the current control module further comprises:
and the Q-axis current value and D-axis current value calculating unit is used for calculating according to the phase current value and the angle estimation value to obtain the Q-axis current value and the D-axis current value.
Preferably, the current control module is further configured to:
and obtaining the phase current value of the motor operation, calling a first Q-axis inductance value, a second Q-axis inductance value, a first D-axis inductance value and a second D-axis inductance value which correspond to a prestored first phase current value and a prestored second phase current value respectively, and calculating the Q-axis inductance and the D-axis inductance value according to the phase current value, the first phase current value, the second phase current value, the first Q-axis inductance, the second Q-axis inductance value, the first D-axis inductance value and the second D-axis inductance value.
Preferably, the PFC operation control part includes a weak magnetic critical voltage calculation module, an alternating current voltage parameter determination module, a weak magnetic critical voltage value amplitude limiting module, an inductance current value calculation module, a PFC switching signal duty ratio calculation module, and a switching signal generation module; wherein
The weak magnetic critical voltage value calculating module is used for calculating and obtaining the weak magnetic critical voltage value when the motor runs according to the Q axis given voltage value, the D axis given voltage value and the modulation coefficient Kmax;
the alternating voltage parameter determination module is used for calculating according to the alternating input voltage value collected by the alternating voltage sampling part to respectively obtain an alternating input voltage polarity identification signal, an alternating input voltage effective value, an alternating input voltage absolute value and a zero-crossing detection signal;
the weak magnetic critical voltage value amplitude limiting module is used for carrying out amplitude limiting on the weak magnetic critical voltage value to obtain the direct current bus voltage given value;
the inductive current given value calculation module is used for calculating according to the direct current bus voltage given value and the direct current bus voltage value to obtain the inductive current given value;
the inductance current value calculation module is used for calculating the inductance current value according to the direct current bus current value;
the PFC switch signal duty ratio calculation module is used for calculating to obtain the PFC switch signal duty ratio signal according to the inductance current given value and the inductance current value;
the switching signal generating module is configured to calculate a switching signal according to the PFC switching signal duty cycle signal, the ac input voltage polarity indication signal, and the ac voltage zero-crossing signal to control the first switching tube or the second switching tube to switch.
Preferably, the D-axis given current value calculation module includes:
the flux weakening controller is used for calculating the maximum output voltage of the inverter and the amplitude of the output voltage of the inverter to obtain an initial value of a given current value of a D axis;
and the amplitude limiting unit is used for carrying out amplitude limiting processing on the D-axis given current value initial value so as to obtain the D-axis given current value.
In order to achieve the above object, the present invention further provides a motor control system, including the PFC circuit.
In order to achieve the purpose, the invention also provides a variable frequency air conditioner which comprises the motor control system.
The invention provides a PFC circuit applied to a motor control system, which comprises a reactor, a rectifying part, a current detecting part, a filter circuit, an alternating voltage sampling part, a direct voltage sampling part and an operation control part, wherein the rectifying part is formed by connecting a rectifying unit and a switching unit in parallel, wherein the rectifying unit comprises four rectifying diodes which are connected in parallel in pairs and then connected in series, the switching unit is connected in series with two switching tubes, so that a full-wave rectifying circuit is formed, the operation control part comprises a PFC operation control part, and a PFC switch duty cycle signal is generated according to an alternating current input voltage value, a direct current bus current value and a direct current bus voltage given value, so that the switching tubes of the rectifying part are driven to work, and power factor correction is carried out on input alternating current. Compared with the conventional PFC circuit, the PFC circuit provided by the embodiment of the invention can effectively improve the efficiency and reduce the common-mode noise, so that the reliability of the whole motor control system is improved.
Drawings
Fig. 1 is a schematic circuit diagram of a PFC circuit according to a first embodiment of the present invention;
fig. 2 is another schematic circuit diagram of the PFC circuit according to the first embodiment of the present invention;
FIG. 3 is a schematic diagram of a current loop of the reactor in the first embodiment when the reactor stores energy, wherein the current flows from the L line;
FIG. 4 is a schematic view of a current loop for charging the electrolytic capacitor with a current from line L in the first embodiment;
FIG. 5 is a schematic diagram of a current loop of the reactor in the first embodiment when the reactor stores energy, wherein the current is from the N line;
FIG. 6 is a schematic view of a current loop for charging the electrolytic capacitor with a current from line N in the first embodiment;
fig. 7 is a sine wave modulation waveform diagram of a PWM signal for controlling the inverter in the first embodiment;
fig. 8 is a schematic diagram illustrating a correspondence relationship between a PWM signal for controlling the inverter and an isosceles triangle carrier signal in the first embodiment;
fig. 9 is a schematic diagram of the PWM signal waveform and the ac current waveform outputted from the PFC operation control section 51 according to the second embodiment of the PFC circuit of the present invention;
fig. 10 is a functional block diagram of a motor operation control unit according to a third embodiment of the PFC circuit of the present invention;
FIG. 11 is a graph of D-axis inductance and Q-axis inductance of a motor as a function of current;
fig. 12 is a schematic diagram of functional modules of a PFC operation control unit according to a fourth embodiment of the PFC circuit of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
Referring to fig. 1, fig. 1 is a schematic diagram of a PFC circuit according to a first embodiment of the present invention, and for convenience of description, only the parts related to the embodiment of the present invention are shown, and detailed descriptions are as follows:
the PFC of the embodiment of the invention is applied to a motor control system and comprises a reactor L, a rectifying part 4, a current detecting part 3, a filter circuit 7, an alternating voltage sampling part 2, a direct voltage sampling part 6 and an operation control part 5; the reactor L is connected to the input end of the ac power supply 1, and the reactor L and the rectifying unit 4 are connected in series in the ac power supply circuit; the output end of the rectifying part 4 is connected with a direct current bus, and the filter circuit 7 is connected with the rectifying part 4 through the direct current bus; the current detection part 3 is connected in series with the direct current bus; wherein
The filter circuit 7 is used for smoothing and filtering the direct current output by the rectifying module to output a direct current bus voltage, and in the figure, the filter circuit 7 mainly comprises an electrolytic capacitor EC.
The current detection part 3 is used for detecting a current value Idc of the direct current bus, here, the current detection part 3 may be based on a current sampling circuit of a series resistor type, and then output through a differential circuit connected with two ends of a resistor, and such a sampling circuit belongs to the prior art and is not described herein again.
The ac voltage sampling unit 2 and the dc voltage sampling unit 6 are respectively configured to sample an ac input voltage value Uac and a dc bus voltage value Udc, where the dc voltage sampling unit 6 may be based on a simple voltage division sampling circuit in the figure, which is formed by connecting a first voltage division resistor R4 and a second voltage division resistor R5 in series, and the circuit of the ac voltage sampling unit 2 may be the same as the dc voltage sampling unit 6, or may be based on other existing voltage sampling circuits, such as a voltage sampling circuit of a transformer structure type.
The operation control part 5 comprises a PFC operation control part 51, and the PFC operation control part 51 is configured to obtain a dc bus voltage given value Udref of the motor operation, and generate a PFC switch duty signal to drive a switch tube of the rectifying part 4 to work according to the ac input voltage value Uac, the dc bus voltage value Udc, the dc bus current value Idc, and the dc bus voltage given value Udref, so as to perform power factor correction on the input ac.
Specifically, the rectifying unit 4 includes a first rectifying unit 41 and a second switching unit 42, the first rectifying unit 41 includes a first branch formed by connecting a first diode D1 and a second diode D2 in parallel and a second branch formed by connecting a third diode D3 and a fourth diode D4 in parallel, the first branch and the second branch are connected in series, the second switching unit 42 includes a first switching tube S7 and a second switching tube S8 connected in series and having freewheeling diodes, the first rectifying unit 41 and the second switching unit 42 are connected in parallel, control ends of the first switching tube S7 and the second switching tube S8 are respectively connected to the operation control unit 5, a common junction of the first diode D1 and the second diode D3, and a common junction of the first switching tube S7 and the second switching tube S8 are respectively connected to an L line and an N line of the ac power supply, so as to form an ac power supply loop.
In the figure, the first diode D1, the second diode D2, the second diode D3 and the fourth diode D4 may be ordinary low-speed rectifier diodes, and the first switch tube S7 and the second switch tube S8 are MOS (Metal oxide Semiconductor), but may also be other types of power tubes such as IGBT (Insulated Gate bipolar transistor);
a common anode of the first diode D1 and the second diode D2 which are connected in parallel, and a common cathode of the third diode D3 and the fourth diode D4 which are connected in parallel are connected with an L line of an alternating current power supply; a common connection point of the first switch tube S7 and the second switch tube S8 connected in series is connected with an N line of an alternating current power supply, one end of the first switch tube S7 and the second switch tube S8 connected in series is connected with a common cathode of the first diode D1 and the second diode D2 connected in parallel, the other end of the first switch tube S7 and the second switch tube S8 connected in series is connected with a common anode of the third diode D3 and the fourth diode D4 connected in parallel, and control ends of the first switch tube S7 and the second switch tube S8 are respectively connected with the operation control part 5;
the anode and the cathode of the freewheeling diode D5 are respectively connected to the D pole and the S pole of the first switching tube S7, the freewheeling diode D6 is integrated inside the first switching tube S7, the anode and the cathode of the freewheeling diode D6 are respectively connected to the D pole and the S pole of the second switching tube S8, and the freewheeling diode D6 is integrated inside the second switching tube S8. In a rectifier circuit which needs large current to work, the types of rectifier diodes needing matching can be difficult to adapt, or the selectable types are few, so that the price is increased, the combination of sampling two parallel connection can enable the current of a single diode to be only half of the matching current, so that the adaptation is relatively easy, and the cost can be reduced, for example, the rectifier circuit needs the current requirement of 30A, the specification of 30A is difficult to adapt to the single rectifier diode, or the cost is higher, the rectifier diode sampling a single 20A is easy to adapt, and even if the cost of the two parallel connection is much lower than that of the single rectifier diode, the circuit cost can be greatly reduced by the combination form of two parallel connection.
Therefore, the first rectifying unit 41 of the present embodiment is composed of the first diode D1 and the second diode D2, and the third diode D3 and the fourth diode D4, which are connected in parallel and then connected in series, and the diode types are easily adapted to each other, so that the cost of the whole circuit can be effectively reduced.
The current detection unit 3 described above may be connected in series to the positive electrode line side of the dc bus in fig. 1, or may be connected in series to the negative electrode line side of the dc bus, and as shown in fig. 2, has the same function of detecting the dc bus current value Idc as in fig. 1. The current detection unit 3 may be connected in series between the rectifying unit 4 and the filter circuit 7.
The working principle of the PFC circuit shown in this embodiment is as follows: as shown in fig. 3, when the PFC operation control unit 51 controls the first switching tube S7 to be turned on and the second switching tube S8 to be turned off, the ac power current flows from the live line, i.e., the L line, through the first diode D1 and the second diode D2, the S pole and the D pole of the first switching tube S7, and the reactor L returns to the zero line, i.e., the N line of the ac power to form a loop, so that energy storage of the reactor L is realized; when the PFC operation control unit 51 controls the first switching tube S7 to be turned off, as shown in fig. 4, an induced electromotive force is generated in the reactor L, and the direction of the current generated by the electromotive force flowing through the reactor L coincides with the direction of the current before the first switching tube S7 is turned off, and at this time, the current generated by the induced electromotive force of the reactor L returns to the ac power supply neutral line, i.e., the N line configuration circuit through the first diode D1 and the second diode D2, the current detection unit 3, the electrolytic capacitor EC, the flywheel diode D6 of the second switching tube S8, the reactor L, and the current detection unit 3 to charge the electrolytic capacitor EC, thereby realizing the power factor correction, i.e., the phase correction of the ac voltage and the ac current input from the rectifier unit 4 when the ac power supply current starts from the L line.
When the PFC operation control unit 51 controls the first switching tube S7 to be turned off and the second switching tube S8 to be turned on, as shown in fig. 5, the ac power current flows from the zero line, i.e., the N line, through the reactor L, the S and D poles of the second switching tube S8, the third diode D3, and the fourth diode D4 to the ac power live line, i.e., the L line, to form a loop, thereby storing energy in the reactor L; when the PFC operation control unit 51 controls the second switching tube S8 to be turned off, as shown in fig. 6, an induced electromotive force is generated in the reactor L, and the direction of the current generated by the electromotive force flowing through the reactor L coincides with the direction of the current before the second switching tube S8 is turned off, and at this time, the current generated by the induced electromotive force of the reactor L returns to the L-line configuration circuit, which is the live line of the ac power supply, through the freewheeling diode D5 of the first switching tube S7, the current detection unit 3, the electrolytic capacitor EC, the third diode D3, and the fourth diode D4 to charge the electrolytic capacitor EC, thereby achieving power factor correction, which is the phase correction of the ac voltage and the ac current input from the rectifier unit 4 when the ac power supply current starts from the N-line direction.
Therefore, the PFC operation controller 51 controls the first switch tube S7 and the second switch tube S8 to be alternately turned on and off, respectively, thereby implementing the power factor correction function in the full-wave rectification mode.
Further, the motor control system cited in the PFC circuit according to the embodiment of the present invention further includes a phase current sampling unit 9, where the current sampling unit 9 is configured to sample a phase current signal of the motor 10 and input the phase current signal to the motor operation control unit 5, and as shown in phase current signals Iu, Iv, and Iw in fig. 1, the current sampling unit 9 may be implemented based on a current sampling scheme with three resistors and a single electron, which belongs to the prior art and is not described herein again.
The input end of the inverter 8 is connected with a direct current bus, the rectifying bus provides the direct current power supply for the inverter 8, the output end of the inverter 8 is connected with the motor 10, the operation control part 5 further comprises a motor operation control part 52, the motor operation control part 52 is used for calculating and generating a pulse width signal according to a direct current bus voltage value Udc, phase current signals Iu, Iv and Iw of the motor and a target rotating speed value omega ref of the motor 10, the operation control part 5 further generates a triangular carrier signal, and generates a PWM control signal to the inverter 8 according to the triangular carrier signal and the pulse width signal so as to drive the motor 10 to operate.
Specifically, the motor operation control unit 52 obtains the dc bus voltage value Udc and the target rotation speed value ω ref of the motor 10 at the same time according to the sampled phase current signals Iu, Iv, Iw of the motor 10, calculates, and finally outputs six PWM control signals to the inverter 8, wherein the PWM control signals are based on the sine wave modulation principle macroscopically, as shown in fig. 7, and the isosceles triangular carrier S2 is modulated by the sine wave voltage signal S3 to obtain one PWM control signal waveform, as shown in S1, the PWM period T of which is generally set to 100us-250us, and finally the motor 10 is driven by the inverter 8, and the sine waveform is finally formed on three windings of the motor 10 due to the inductance characteristic of the motor windings, as shown in the dotted line waveform S4 in fig. 7.
Because the frequency of PWM is very high, when the motor operation control unit 52 performs pulse width calculation and finally generates a PWM control signal, it is actually realized based on the voltage space vector pulse width modulation principle (SVPWM), that is, by calculating the generated pulse width signal, and generating a continuous triangular carrier signal by a timer inside the motor operation control unit 52, and finally outputting the PWM control signal by comparing the pulse width signal with the triangular carrier signal, the PWM control signal has six paths, and respectively controls six switching tubes S1-S6 of the inverter 8 to operate, and finally the inverter 8 outputs a three-phase driving signal to the motor 10 to realize the driving operation of the motor 10.
As shown in fig. 8, the schematic diagram of the waveform of the triangular carrier signal generated by the timer in the motor operation control unit 52 is shown as S6, the pulse width signals thereof are shown as Du1, Du2 and Du3, the actual software generates the PWM control signal waveform by sending the pulse width signal to the comparison register, and finally, one of the PWM control signals is generated by the timer based on the triangular carrier S6 as shown as S5, wherein each period of the triangular carrier corresponds to one period of the PWM control signal. Wherein, each triangle in the triangle carrier signal of S6 is an isosceles triangle, the peak of each isosceles triangle is the same as the middle time of the effective pulse width of the PWM control signal in the carrier period of the isosceles triangle, and as shown in the figure, the peak of the first isosceles triangle corresponds to the effective pulse width of the first PWM pulse waveform, i.e. the time position of the midpoint b of the time a-c in the figure. Different PWM control signals with different effective pulse widths are finally generated through different pulse width signals. Six PWM control signals are added into six switching tubes of the inverter 8 and control the motor 10 to finally form three vectors with space difference of 120 degrees, finally voltage vector signals changing along with time are synthesized, the amplitude of the voltage vector signals is constant, and the voltage vector signals rotate according to the same frequency of sine waves, so that the motor 10 can run under the control of the voltage vector signals.
The PFC circuit applied to the motor control system of the embodiment of the invention comprises a reactor L, a rectifying part 4, a current detecting part 3, a filter circuit 7, an alternating voltage sampling part 2, a direct voltage sampling part 6 and an operation control part 5, wherein the rectifying part 4 is formed by connecting a rectifying unit consisting of four rectifying diodes which are connected in parallel and then connected in series in pairs and a switching unit consisting of two switching tubes which are connected in series in parallel, so as to form a full-wave rectifying circuit, the operation control part comprises a PFC operation control part 51, and a PFC switch duty cycle signal is generated according to an alternating current input voltage value Uac, a direct current bus voltage value Udc, a direct current bus current value Idc and a direct current bus voltage given value Udref to drive the switching tubes of the rectifying part 4 to work, so as to correct the power factor of the input alternating current. Compared with the conventional PFC circuit, the PFC circuit provided by the embodiment of the invention can effectively improve the efficiency and reduce the common-mode noise, so that the reliability of the whole motor control system is improved.
Further, as a second embodiment of the PFC circuit provided by the present invention, based on the first embodiment of the PFC circuit of the present invention, in the present embodiment, the current value I through the reactor is determined by detecting the direct-current bus current IdcLThe current detector 3 samples the current at an intermediate timing when the first switching tube S7 or the second switching tube S8 is turned off.
In the first placeIn the embodiment, it can be seen from the explanation of the operation principle of the PFC circuit that when the PFC operation control unit 51 controls the first switching tube S7 or the second switching tube S8 to be turned on, the ac power supply current stores energy in the reactor L, that is, the current I passing through the reactor at this timeLSince the electrolytic capacitor EC is not charged at this time without passing through the electrolytic capacitor EC, no current flows in the dc bus, and only when the PFC operation control unit 51 controls the first switching tube S7 or the second switching tube S8 to be turned off, the current I generated by the induced electromotive force generated in the reactor LLThe electrolytic capacitor EC is charged only when there is current on the dc bus, so that the current on the dc bus should be detected during the period when the first switch tube S7 or the second switch tube S8 is turned off in order to accurately detect the current on the dc bus.
When the PWM signal waveform output from the PFC operation control unit 51 shown in fig. 9, for example, S7, controls the switching state of the first switching tube S7 or the second switching tube S8 to switch to control the PFC circuit to perform power factor correction, the current detection unit 3 samples the dc bus current at the time point of controlling the first switching tube S7 or the second switching tube S8 in one PWM control signal period, which is the middle time point of the time period T2 in the off time period diagram, which is the time point of T1 in the diagram, and the reactor L performs the conversion of energy storage and release when the switching state of the first switching tube S7 or the second switching tube S8 is switched, and the reactor L stores energy during the on time period of the switching tube and passes through the current value I of the reactorLThe current value I passing through the reactor is increased and the discharge of the filtered electrolytic capacitor is discharged by the induced electromotive force generated by the reactor L during the closing of the switch tubeLReduce the alternating current I passing through the reactor LLThe waveform diagram of the PWM following the switching tube is shown as S8 in the figure, where the current of the device increases at t1 when the switching tube is turned on, and the current decreases during t2 when the switching tube is turned off, so it is important to select a proper current sampling point, otherwise the sampling error is large. Because the current i passing through the reactor is generated when the first switch tube S7 or the second switch tube S8 is turned onLThrough the reactor only when the first switching tube S7 or the second switching tube S8 is closed without passing through the electrolytic capacitor ECCurrent iLOnly through the electrolytic capacitor, i.e. the reactor at that time, iLFor the dc bus current value Idc, it is experimentally determined that the current sampled at the intermediate time during the switching tube off period can represent the actual current value of the ac current in each PWM period with a high accuracy, as shown by ILSample is the current value obtained by actual sampling, and the magnitude of the sample is close to the current I of the reactorLThe average value of the PWM control signal device change in the whole switching tube is used as the current value I passing through the reactorLTherefore, the accuracy of the sampling current value is ensured, and the FC operation control part 51 is ensured to control the switch tube to work accurately, so that the accuracy of power factor correction is improved.
Further, as a third embodiment of the PFC circuit according to the present invention, based on the first embodiment of the PFC circuit according to the present invention, as shown in fig. 10, the motor operation control unit 52 of the motor control system according to the present embodiment further includes:
a position/speed estimation module 521 for estimating a rotor position of the motor to obtain a rotor angle estimation value θ est and a motor speed estimation value ω est of the motor 10;
the Q-axis given current value Iqref calculation module 522 is configured to calculate a Q-axis given current value Iqref according to the motor target rotation speed value ω ref and the motor speed estimation value ω est;
a D-axis given current value Idref calculation module 523 for calculating a D-axis given current value Idref from the maximum output voltage Vmax of the inverter and the output voltage amplitude V1 of the inverter;
a current control module 524, configured to calculate a pulse width signal according to the Q-axis given current value Iqref, the D-axis given current value Idref, the motor speed estimation value ω est, the dc bus voltage value Udc, and the phase current values Iu, Iv, and Iw sampled by the motor 10, and generate a PWM control signal to the inverter 8 according to the triangular carrier signal and the pulse width signal, so as to drive the motor 10 to operate
Specifically, the motor in the embodiment of the inventionThe position/speed estimation module 521 may determine the rotor angle estimation value θ est and the motor speed estimation value ω est of the motor 10 by flux linkage observation, and specifically, the function may be implemented according to the voltage V on the two-phase stationary coordinate systemα、VβAnd current Iα、IβThe estimated values of the effective magnetic fluxes of the compressor motor in the axial directions of the two-phase stationary coordinate systems α and β are calculated according to the following formula (1):
wherein ,andthe effective flux, V, of the motor in the α and β axial directions, respectivelyα and VβVoltage in the direction of the α and β axes, Iα and IβCurrent in the direction of the α and β axes, R is stator resistance, LqIs the q-axis inductance parameter of the motor.
Then, a rotor angle estimation value θ est of the compressor motor and a motor actual rotation speed value ω est are calculated according to the following equation (2):
wherein ,Kp_pll and Ki_pllRespectively, a proportional integral parameter, thetaerrAs an estimate of the deviation angle, ωfThe bandwidth of the velocity low pass filter.
Specifically, the Q-axis given current value calculation block 522 includes a superposition unit and a PI regulator. The PI regulator is used for carrying out PI regulation according to the difference between the motor target rotating speed value omega ref and the motor speed estimation value omega est output by the superposition unit so as to output a Q-axis given current value Iqref.
Specifically, the D-axis given current value calculation module 523 includes a field weakening controller and a limiting unit, wherein the field weakening controller is configured to calculate the maximum output voltage Vmax of the inverter 8 and the output voltage amplitude V1 of the inverter 8 to obtain a D-axis given current value initial value Id0, and the limiting unit is configured to perform a limiting process on the D-axis given current value initial value Id0 to obtain a D-axis given current value Idref.
In the embodiment of the present invention, the field weakening controller may calculate the D-axis given current value initial value Id0 according to the following equation (3):
wherein ,Id0Setting the initial value of current for D axis, KiIn order to integrate the control coefficients of the motor, V1is the output voltage amplitude, v, of the inverterdIs D-axis voltage, vqIs the Q-axis voltage, VmaxIs the maximum output voltage, V, of the inverter 8dcWhich is the dc bus voltage output by the rectifier 4.
In an embodiment of the present invention, the clipping unit obtains the D-axis given current value according to the following equation (4):
where Idref is the D-axis given current value, IdemagFor demagnetizing currents of electric machinesA limit value.
Specifically, the current control module 524 performs the following calculation:
u, V, W three-phase current values Iu, Iv and Iw are obtained by sampling the motor 10, Clark conversion is carried out by a three-phase static-two-phase static coordinate conversion unit, and the current I of the motor in the axial direction of the two-phase static coordinate systems α and β is obtained based on the following formula (5)α and Iβ
Iα＝Iu
Then according to the rotor angle estimated value thetaestThe real current values Iq and Id of the d axis and the q axis in the two-phase rotating coordinate system are calculated by the following formula (6) through Park conversion performed by the two-phase stationary-two-phase rotating coordinate conversion unit.
Id＝Iαcosθest+Iβsinθest
Iq＝-Iαsinθest+Iβcosθest(6)
The calculation of the actual current values Iq and Id of the D axis and the Q axis by the Q axis current value and D axis current value calculation units in the current control module 524 is realized by the formula (5) and the formula (6) described above.
Further, the current control module 524 may calculate the Q-axis given voltage value and the D-axis given voltage value according to the following equation (7):
wherein Vq is a Q-axis given voltage value, Vd is a D-axis given voltage value, Iqref is a Q-axis given current value, Idref is a D-axis given current value, Iq is a Q-axis current,id is D-axis current, Kpd and Kid are D-axis current control proportional gain and integral gain respectively, Kpq and Kiq are Q-axis current control proportional gain and integral gain respectively, omega is motor rotation speed, Ke is motor 10 back electromotive force coefficient, Ld and Lq are D-axis and Q-axis inductance respectively, the two parameters can be provided by a motor manufacturer, particularly, rated values can be obtained according to a curve graph of the D-axis and the Q-axis of the motor provided by the motor manufacturer along with the change of the current,denotes the integral of x (τ) over time.
Further, in order to further accurately obtain the D-axis inductor Ld and the Q-axis inductor Lq, the current control module 524 is further configured to: the method comprises the steps of obtaining phase current values of motor operation, calling a first Q-axis inductance, a second Q-axis inductance, a first D-axis inductance and a second D-axis inductance which correspond to a prestored first phase current value and a prestored second phase current value respectively, and calculating the Q-axis inductance and the D-axis inductance according to the phase current values, the first phase current value, the second phase current value, the first Q-axis inductance, the second Q-axis inductance, the first D-axis inductance and the second D-axis inductance. Specifically, the phase current signals Iu, Iv, and Iw of the motor 10 acquired by the current sampling unit 9 are obtained, and the three phase currents have the same magnitude and only need to be one of the three phase currents. A graph of a change curve of a D-axis inductance and a Q-axis inductance of a motor provided by a motor manufacturer along with a current is shown in fig. 11, wherein i is a winding current of the motor, i.e., a phase current value, at this time, a first Q-axis inductance Lq1, a second Q-axis inductance Lq2, a first D-axis inductance Ld1 and a second D-axis inductance Ld2 corresponding to a first phase current value i1 and a second phase current value i2 respectively can be prestored through the graph, and the D-axis inductance Ld and the Q-axis inductance Lq corresponding to a currently detected phase current i can be calculated according to the following difference calculation formula:
Ld＝Ld1+(Ld2-Ld1)*(i-i1)/(i2-i1)
Lq＝Lq1+(Lq2-Lq1)*(i-i1)/(i2-i1)
through the formula, the values of the D-axis inductance Ld and the Q-axis inductance Lq corresponding to the current phase current of the motor 10 can be relatively accurately determined.
After the Q-axis given voltage value Vq and the D-axis given voltage value Vd are obtained, the angle estimation value theta of the motor rotor can be obtainedestAnd carrying out Park inverse transformation on Vq and Vd through a two-phase rotation-two-phase static coordinate conversion unit to obtain voltage values V α and V β on a fixed coordinate system, wherein a specific transformation formula (8) is as follows:
where θ is the rotor angle of the motor 10, the rotor angle estimate θ est may be used.
Further, Clark inverse transformation can be performed by the two-phase static-three-phase static coordinate conversion unit according to the voltage values V α and V β on the fixed coordinate system to obtain three-phase voltages Vu, Vv and Vw, and the specific transformation formula (9) is as follows:
Vu＝Vα
then, the duty ratio calculation unit can perform duty ratio calculation according to the direct current bus voltage Udc and the three-phase voltages Vu, Vv and Vw to obtain duty ratio control signals, namely three-phase duty ratios Du, Dv and Dw, and the specific calculation formula (10) is as follows:
Du＝(Vu+0.5Vdc)/Vdc
Dv＝(Vv+0.5Vdc)/Vdc
Dw＝(Vw+0.5Vdc)/Vdc(10)
wherein Udc is a dc bus voltage.
The three-phase duty ratio signal here includes three pulse width signals, such as the duty ratio signals Du1, Du2, and Du3 corresponding to the duty ratio Du of one phase at different times in fig. 8, and finally generates corresponding three PWM control signals to the three switching tubes of the upper arm of the inverter 8 through the triangular carrier signal generated by the timer in the operation control unit, and the three control signals of the lower arm and the three PWM control signals complementary to the three control signals, so that the three-phase duty ratio signal here actually includes six PWM control signals, and finally controls the six switching tubes of the inverter 4 according to the six PWM control signals corresponding to the three-phase duty ratios Du, Dv, and Dw, so as to realize the driving operation of the motor 10.
Further, as a fourth embodiment of the PFC circuit provided by the present invention, based on the third embodiment of the PFC circuit provided by the present invention, as shown in fig. 12, in the present embodiment, the PFC operation control part 51 includes a weak magnetic critical voltage Us calculating module 511, an alternating current voltage parameter determining module 512, a weak magnetic critical voltage value Us clipping module 513, and an inductance current value ILA calculation module 516, a PFC switching signal duty ratio calculation module 515, and a switching signal generation module 517;
and the weak magnetic critical voltage value Us calculating module 511 is used for calculating a Q-axis given voltage value Vq, a D-axis given voltage value Vd and a modulation coefficient Kmax to obtain the weak magnetic critical voltage value Us when the motor runs.
The ac voltage parameter determining module 512 is configured to calculate and obtain an ac input voltage polarity identification signal, an ac input voltage effective value Urms, an ac input voltage absolute value | Uac | and a zero-crossing detection signal according to the ac input voltage value Uac collected by the ac voltage sampling unit 2, where the ac input voltage value Uac is a voltage value varying in a sine wave, and thus the parameter values are not difficult to obtain by analyzing and calculating a real-time voltage value thereof in a sine wave period.
And the weak magnetic critical voltage value Us amplitude limiting module 513 is used for carrying out amplitude limiting on the weak magnetic critical voltage value Us to obtain a direct current bus voltage given value Udref.
Given value of inductive current ILrefA calculating module 514, configured to calculate a given value I of the inductive current according to the given value Udref of the dc bus voltage and the given value Udc of the dc bus voltageLref；
Value of inductance current ILA calculating module 516, configured to calculate an inductance current value I according to the dc bus current value IdcL；
A PFC switch signal duty ratio calculation module 515, configured to calculate a given value I of the inductor current according to the given value ILrefAnd the value of the inductance current ILCalculating to obtain a PFC switch signal duty ratio signal;
the switching signal generating module 517 is configured to calculate a switching signal according to the PFC switching signal duty cycle signal, the ac input voltage polarity identification signal, and the ac voltage zero-crossing signal to control the switching operation of the first switching tube S7 or the second switching tube S8.
Specifically, the weak magnetic critical voltage value Us clipping module 513 calculates based on the following formula (11):
where Vd is a D-axis given voltage value and Vq is a Q-axis given voltage value, which are calculated based on equation (7) by the current control module 524 of the motor operation control unit 52 in the third embodiment, and Kmax is a modulation factor, that is, a ratio of the maximum output voltage of the inverter to the bus voltage. If linear modulation is considered, then
Further, the weak magnetic critical voltage value Us amplitude limiting module 513 limits the weak magnetic critical voltage value Us by [ U [ ]dc_min,Udc_max]Then obtaining the direct current bus electricityA voltage command value Udref, where Udc_minDetermined by the input voltage, usually taking Udc_min＝Uac_max+U0,Uac_maxIs the maximum value of the AC voltage, U0As a constant value, it is recommended to take 5V to 10V. U shapedc_maxDetermined according to the withstand voltage of the system and a certain margindc_max＝Urate-U1,UrateFor the device withstand voltage value, the IPM module withstand voltage used in this embodiment may be 500V, i.e., Urate＝500V，U150V-100V is recommended to reserve the withstand voltage margin, U in the embodiment1May be taken as 100V.
Further, the given value of the inductive current ILrefThe calculation module 514 calculates the given value I of the inductor currentLrefFirstly, making a difference between a given value Udref of the direct-current bus voltage and a value Udc of the direct-current bus voltage, carrying out PI control, multiplying the difference by an absolute value | Uac | of the power supply voltage, and then multiplying by the reciprocal 1/U of the square of an effective value of the power supply voltage2rms, obtaining the instruction value I of the inductive currentLref。
Further, the value of the inductance current ILThe calculating module 516 calculates the inductance current value ILThen, the inductance current value I is calculated through the direct current bus current value IdcLIn the second embodiment, the dc bus current value Idc is an inductance current value I passing through the reactor L during the turn-off of the first switch tube S7 or the second switch tube S8LTherefore, the inductance current value I can be represented by the DC bus current value IdcL。
Further, when the duty ratio signal of the PFC switching signal is calculated by the duty ratio calculation module 515, the PFC switching signal is given by the inductance current given value ILrefAnd the actual value of the inductor current ILAnd performing PI control to obtain the duty ratio D of the PFC switching signal.
Further, the switching signal generating module 517 finally determines the PWM control signal output to the first switching tube S7 or the second switching tube S8 for switching according to the PFC switching signal duty cycle signal D, the ac input voltage polarity identification signal, and the ac voltage zero-crossing signal, so as to control the PFC circuit to operate.
In the process of calculating and generating the switching signal for controlling the operation of the switching tube, the PFC operation control unit 51 of the embodiment introduces a real-time parameter in the control process of the motor 10 due to the introduction of the motor operation control unit 51 in calculating and generating the PWM control signal for controlling the inverter to finally obtain the relevant parameters of the operation of the motor 10, such as the Q-axis given voltage value Vq and the D-axis given voltage value Vd, to obtain the parameter values for the field weakening control, so that the control of the PFC circuit can monitor the load condition of the motor 10 in real time to change, and thus the control is more accurate.
The invention also provides a motor control system, which can be used for driving the permanent magnet synchronous motor to operate and can be applied to household appliances such as an air conditioner or a washing machine and the like which sample the working of the permanent magnet synchronous motor.
The invention also provides a variable frequency air conditioner which comprises an indoor unit part and an outdoor unit part, wherein the outdoor unit controller and/or the indoor unit controller can comprise the motor control system disclosed by the embodiment of the invention so as to control the operation of the indoor fan or the outdoor compressor, and the reliability of the whole variable frequency air conditioner can be effectively improved.
In the description herein, references to the description of the terms "first embodiment," "second embodiment," "example," etc., mean that a particular method, apparatus, or feature described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, methods, apparatuses, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims (11)

1. A PFC circuit is applied to a motor control system and is characterized by comprising a reactor, a rectifying part, a current detecting part, a filter circuit, an alternating voltage sampling part, a direct voltage sampling part and an operation control part; the reactor is connected with the input end of the alternating current power supply, and the reactor and the rectifying part are connected in series in the alternating current power supply loop; the output end of the rectifying part is connected with a direct current bus, and the filter circuit is connected with the rectifying part through the direct current bus; the current detection part is connected in series with the direct current bus;
the rectifying part comprises a first diode, a second diode, a third diode, a fourth diode, a first switching tube and a second switching tube, wherein the first switching tube and the second switching tube are provided with freewheeling diodes, and a common anode after the first diode and the second diode are connected in parallel and a common cathode after the third diode and the fourth diode are connected in parallel are connected with an L line of an alternating current power supply; the public connecting point of the first switch tube and the second switch tube after being connected in series is connected with an N line of an alternating current power supply, one end of the first switch tube and the second switch tube after being connected in series is connected with a public cathode of the first diode and the second diode after being connected in parallel, the other end of the first switch tube and the second switch tube after being connected in series is connected with a public anode of the third diode and the fourth diode after being connected in parallel, and the control ends of the first switch tube and the second switch tube are respectively connected with the operation control part; wherein,
the current detection part is used for detecting the direct current bus current and obtaining a corresponding direct current bus current value; the filter circuit is used for smoothing and filtering the direct current output by the rectifying module to output direct current bus voltage; the alternating current voltage sampling part is used for detecting alternating current input voltage and obtaining a corresponding alternating current input voltage value; the direct-current voltage sampling part is used for detecting the direct-current bus voltage and obtaining a corresponding direct-current bus voltage value;
the operation control part comprises a PFC operation control part, and the PFC operation control part is used for obtaining a direct current bus voltage given value of motor operation, and generating a PFC switch duty ratio signal according to the alternating current input voltage value, the direct current bus current value and the direct current bus voltage given value to drive a switch tube of the rectification part to work so as to correct the power factor of the input alternating current.
2. The PFC circuit according to claim 1, wherein the current detection section is connected in series between the rectification section and the filter circuit, and a value of a current passing through the reactor is determined by detecting the direct-current bus current.
3. The PFC circuit of claim 2, wherein the current detection part performs current sampling at an intermediate timing when the first switching tube or the second switching tube is turned off.
4. The PFC circuit of claim 1, wherein the motor control system comprises a phase current sampling section and an inverter;
the phase current sampling part is used for sampling a phase current signal of the motor and inputting the phase current signal into the motor operation control part;
the input end of the inverter is connected with the direct current bus, and the output end of the inverter is connected with the motor;
the operation control part also comprises a motor operation control part, the motor operation control part is used for calculating and generating a pulse width signal according to the direct current bus voltage value, the phase current signal of the motor and the target rotating speed value of the motor, the operation control part also generates a triangular carrier signal, and generates a PWM control signal to the inverter according to the triangular carrier signal and the pulse width signal so as to drive the motor to operate.
5. The PFC circuit of claim 4, wherein the motor operation control section comprises:
the position/speed estimation module is used for estimating the rotor position of the motor to obtain a rotor angle estimation value and a motor speed estimation value of the motor;
the Q-axis given current value calculation module is used for calculating a Q-axis given current value according to the target rotating speed value of the motor and the estimated motor speed value;
the D-axis given current value calculation module is used for calculating a D-axis given current value according to the maximum output voltage of the inverter and the output voltage amplitude of the inverter;
and the current control module is used for calculating the phase current value sampled by the motor according to the Q-axis given current value, the D-axis given current value, the motor speed estimation value, the direct-current bus voltage value and the pulse width signal to generate the pulse width signal, and generating the PWM control signal to the inverter according to the triangular carrier signal and the pulse width signal to drive the motor to run.
6. The PFC circuit of claim 5, wherein the D-axis given current value calculation module comprises:
the flux weakening controller is used for calculating the maximum output voltage of the inverter and the amplitude of the output voltage of the inverter to obtain an initial value of a given current value of a D axis;
and the amplitude limiting unit is used for carrying out amplitude limiting processing on the D-axis given current value initial value so as to obtain the D-axis given current value.
7. The PFC circuit of claim 5, wherein the current control module further comprises:
and the Q-axis current value and D-axis current value calculating unit is used for calculating according to the phase current value and the angle estimation value to obtain the Q-axis current value and the D-axis current value.
8. The PFC circuit of claim 5, wherein the current control module is further to:
and obtaining the phase current value of the motor operation, calling a first Q-axis inductance value, a second Q-axis inductance value, a first D-axis inductance value and a second D-axis inductance value which correspond to a prestored first phase current value and a prestored second phase current value respectively, and calculating the Q-axis inductance and the D-axis inductance value according to the phase current value, the first phase current value, the second phase current value, the first Q-axis inductance, the second Q-axis inductance value, the first D-axis inductance value and the second D-axis inductance value.
9. The PFC circuit according to any one of claims 5 to 8, wherein the PFC operation control part comprises a weak magnetic critical voltage calculation module, an alternating voltage parameter determination module, a weak magnetic critical voltage value amplitude limiting module, an inductance current value calculation module, a PFC switching signal duty ratio calculation module and a switching signal generation module; wherein
The weak magnetic critical voltage value calculating module is used for calculating and obtaining the weak magnetic critical voltage value when the motor runs according to the Q axis given voltage value, the D axis given voltage value and the modulation coefficient Kmax;
the alternating voltage parameter determination module is used for calculating according to the alternating input voltage value collected by the alternating voltage sampling part to respectively obtain an alternating input voltage polarity identification signal, an alternating input voltage effective value, an alternating input voltage absolute value and a zero-crossing detection signal;
the weak magnetic critical voltage value amplitude limiting module is used for carrying out amplitude limiting on the weak magnetic critical voltage value to obtain the direct current bus voltage given value;
the inductive current given value calculation module is used for calculating according to the direct current bus voltage given value and the direct current bus voltage value to obtain the inductive current given value;
the inductance current value calculation module is used for calculating the inductance current value according to the direct current bus current value;
the PFC switch signal duty ratio calculation module is used for calculating to obtain the PFC switch signal duty ratio signal according to the inductance current given value and the inductance current value;
the switching signal generating module is configured to calculate a switching signal according to the PFC switching signal duty cycle signal, the ac input voltage polarity indication signal, and the ac voltage zero-crossing signal to control the first switching tube or the second switching tube to switch.
10. A motor control system comprising a PFC circuit according to any one of claims 1 to 9.
11. An inverter air conditioner characterized by comprising the motor control system according to claim 10.
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CN107086770A (en) * 2017-06-30 2017-08-22 广东美的制冷设备有限公司 Pfc circuit and transducer air conditioning
CN107104589A (en) * 2017-06-30 2017-08-29 广东美的制冷设备有限公司 Pfc circuit and transducer air conditioning
CN207884485U (en) * 2018-01-29 2018-09-18 广东美的制冷设备有限公司 Pfc circuit, electric machine control system and transducer air conditioning

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CN108895632A (en) * 2018-05-31 2018-11-27 广东美的制冷设备有限公司 Switching method, air conditioner and the computer readable storage medium of pfc circuit
CN108895632B (en) * 2018-05-31 2020-12-11 广东美的制冷设备有限公司 Switching method of PFC circuit, air conditioner and computer readable storage medium
CN108980093A (en) * 2018-07-27 2018-12-11 青岛斑科变频技术有限公司 A kind of blower drive module for air-conditioning
CN114342243A (en) * 2019-09-02 2022-04-12 三菱电机株式会社 Power conversion device and magnetic saturation detection method for common mode reactor
CN114342243B (en) * 2019-09-02 2022-10-14 三菱电机株式会社 Power conversion device and magnetic saturation detection method for common mode reactor
CN114337228A (en) * 2021-10-25 2022-04-12 杭州先途电子有限公司 Air conditioner controller
CN114362502A (en) * 2021-10-25 2022-04-15 杭州先途电子有限公司 Air conditioner controller
CN114362502B (en) * 2021-10-25 2024-03-12 杭州先途电子有限公司 Air conditioner controller
CN114337228B (en) * 2021-10-25 2024-03-29 杭州先途电子有限公司 Air conditioner controller
CN113829894A (en) * 2021-10-29 2021-12-24 重庆长安新能源汽车科技有限公司 Pulse current determination method and system in high-frequency pulse heating process of power battery

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