阅读说明：本技术 一种含pfc的电机驱动电路及其控制方法 (Motor driving circuit containing PFC and control method thereof ) 是由 刘斌 周镇 胡质良 李俊 于 2020-08-04 设计创作，主要内容包括：本发明提供了一种含PFC的电机驱动电路及其控制方法。该含PFC的电机驱动电路包括PFC电路、储能续流电路和逆变电路,其中,PFC电路用以调整电流波形,提高功率因数；储能续流电路用以向所述逆变电路供应逆变驱动电流；逆变电路用以驱动三相电机。本发明的电机驱动电路能够适用于不同功率电机,实现软启动,提高了效率,具有高功率因数、低电流谐波含量、高效率等优点。(The invention provides a motor driving circuit containing PFC and a control method thereof. The motor driving circuit with the PFC comprises a PFC circuit, an energy storage follow current circuit and an inverter circuit, wherein the PFC circuit is used for adjusting current waveform and improving power factor; the energy storage follow current circuit is used for supplying an inversion driving current to the inversion circuit; the inverter circuit is used for driving the three-phase motor. The motor driving circuit can be suitable for motors with different powers, realizes soft start, improves efficiency, and has the advantages of high power factor, low current harmonic content, high efficiency and the like.)

1. A motor driving circuit containing PFC comprises a PFC circuit, an energy storage follow current circuit and an inverter circuit, wherein,

the PFC circuit comprises a power switch tube Q₁Power switch tube Q₂Power switch tube Q₃Power switch tube Q₄Power switch tube Q₅Power switch tube Q₆Diode D₁Diode D₂Diode D₃Diode D₄Diode D₅And a diode D₆Power switch tube Q₁Collector electrode of (2), and power switch tube Q₂Collector and diode D₁Is connected with the cathode of the power switch tube Q₃Collector electrode of (2), and power switch tube Q₄Collector and diode D₃Is connected with the cathode of the power switch tube Q₅Collector electrode of (2), and power switch tube Q₆Collector and diode D₅The cathodes of the two electrodes are connected; power switch tube Q₂Emitter and diode D₂Is connected with the anode of the power switch tube Q₄Emitter and diode D₄Is connected with the anode of the power switch tube Q₆Emitter and diode D₆The anodes of the anode groups are connected; diode D₂Cathode of (2), diode D₄Cathode of (2), diode D₆The cathode of the energy storage freewheeling circuit is connected with the first end of the energy storage freewheeling circuit; diode D₁Anode of (2), diode D₃Anode of (2), diode D₅Is connected with the second end of the energy storage freewheeling circuit;

the inverter circuit comprises a power switch tube Q₁' power switch tube Q₂' power switch tube Q₃' power switch tube Q₄' power switch tube Q₅' power switch tube Q₆', diode D₁', diode D₂', diode D₃', diode D₄', diode D₅' AND diode D₆', diode D₁' cathode, diode D₃' cathode, diode D₅' the cathode of the power amplifier is connected with the first end of the energy storage follow current circuit; diode D₁' Anode and power switch tube Q₁' emitter-connected, diode D₃' Anode and power switch tube Q₃' emitter-connected, diode D₅' Anode and power switch tube Q₅The emitters of' are connected; power switch tube Q₁' collector and diode D₂The cathode ofPower switch tube Q₃' collector and diode D₄' the cathode of the power switch tube Q is connected₅' collector and diode D₆' connected to the cathode; diode D₂' Anode and power switch tube Q₂' emitter-connected, diode D₄' Anode and power switch tube Q₄' emitter-connected, diode D₆' Anode and power switch tube Q₆The emitters of' are connected; diode D₂' cathode, diode D₄' cathode, diode D₆' the cathode of the rectifier is connected to a second terminal of the energy storage freewheeling circuit.

2. The PFC-containing motor drive circuit of claim 1, wherein: the energy storage follow current circuit comprises an inductor L₁Inductance L₁Is the first end of the energy storage freewheeling circuit, and an inductor L₁And the other end of the second diode is the second end of the energy storage freewheeling circuit.

3. The PFC-containing motor drive circuit of claim 1, wherein: the power switch tube Q₁Power switch tube Q₂Power switch tube Q₃Power switch tube Q₄Power switch tube Q₅Power switch tube Q₆Power switch tube Q₁' power switch tube Q₂' power switch tube Q₃' power switch tube Q₄' power switch tube Q₅' power switch tube Q₆' MOS tube or IGBT tube respectively.

4. The control method of a motor driving circuit having PFC according to any of claims 1 to 3, comprising PFC circuit control and inverter circuit control, wherein,

the PFC circuit control comprises the following steps:

dividing a fundamental wave period into twelve sectors according to the mutual relation of three-phase power supply voltages;

secondly, amplitude detection is carried out on the currently input three-phase power supply voltage signal, and the sector and the phase of the three-phase power supply voltage at the current moment are judged;

step three, respectively defining high voltage phase, medium voltage phase and low voltage phase according to the size of the three-phase power supply voltage in each sector: when the amplitude of the medium voltage phase voltage is positive, executing a step four; when the amplitude of the medium voltage phase voltage is negative, executing a fifth step;

conducting the negative power switch tube corresponding to the low voltage all the time, simultaneously conducting PWM control on the positive power switch tube corresponding to the high voltage and the positive power switch tube corresponding to the medium voltage, and closing the other three power switch tubes in the sector all the time;

conducting the positive power switch tube corresponding to the high voltage phase all the time, simultaneously conducting PWM control on the negative power switch tube corresponding to the medium voltage phase and the negative power switch tube corresponding to the low voltage phase, and closing the other three power switch tubes in the sector all the time;

the inverter circuit control comprises the following steps:

step one, amplitude detection is carried out on a current three-phase motor induced voltage signal, and the current three-phase motor induced voltage signal is respectively defined as a high voltage phase, a medium voltage phase and a low voltage phase according to the magnitude of the three-phase motor induced voltage;

step two, calculating three-phase given current of the motor according to a motor control principle, and respectively defining the three-phase given current as a high current phase, a medium current phase and a low current phase according to the magnitude of the three-phase given current (taking the direction of the motor as the positive direction of the current): when the phase current amplitude of the medium current is positive, executing a step three; when the phase current amplitude of the medium current is negative, executing a step four;

step three, the upper bridge arm power switch tube corresponding to the low current phase is always conducted, wherein when the amplitude of the induced voltage of the phase corresponding to the high current is larger than that of the phase corresponding to the medium current, the step five is executed; when the amplitude of the high-current corresponding phase induced voltage is smaller than that of the medium-current corresponding phase induced voltage, executing a sixth step;

step four, the lower bridge arm power switching tube corresponding to the high current phase is always conducted, wherein step seven is executed when the amplitude of the induced voltage of the phase corresponding to the medium current is larger than that of the phase corresponding to the low current; when the amplitude of the induced voltage of the phase corresponding to the medium current is smaller than that of the induced voltage of the phase corresponding to the low current, executing a step eight;

step five, always conducting the lower bridge arm power switching tube corresponding to the high current phase, and performing PWM control on the lower bridge arm power switching tube corresponding to the medium current phase;

step six, always conducting the lower bridge arm power switching tube corresponding to the medium current phase, and performing PWM control on the lower bridge arm power switching tube corresponding to the high current phase;

step seven, conducting the upper bridge arm power switch tube corresponding to the low current phase all the time, and carrying out PWM control on the upper bridge arm power switch tube corresponding to the medium current phase;

and step eight, always conducting the upper bridge arm power switch tube corresponding to the medium current phase, and performing PWM control on the upper bridge arm power switch tube corresponding to the low current phase.

5. The method of claim 4, wherein: the PFC circuit controls the current of the inductor L1 to be equal to the maximum term of the absolute value of the given current of the three phases of the motor.

Technical Field

The invention relates to an electronic driving technology, in particular to a motor driving circuit containing PFC and a control method thereof.

Background

Motors are ubiquitous in industrial settings. The high-power motor can generate larger current impact at the starting moment, so that the voltage of a power grid is reduced, and the normal operation of other electric equipment is influenced. Meanwhile, the motor winding can be heated by overlarge starting current, so that the insulation aging is accelerated, and the service life of the motor is influenced.

Disclosure of Invention

Based on the above, the invention provides the motor driving circuit containing the PFC and the control method thereof, wherein the motor driving circuit can be applied to different powers and can realize soft start.

In order to realize the purpose of the invention, the invention adopts the following technical scheme:

a motor driving circuit containing PFC comprises a PFC circuit, an energy storage follow current circuit and an inverter circuit, wherein,

the PFC circuit comprises a power switch tube Q₁Power switch tube Q₂Power switch tube Q₃Power switch tube Q₄Power switch tube Q₅Power switch tube Q₆Diode D₁Diode D₂Diode D₃Diode D₄Diode D₅And a diode D₆Power switch tube Q₁Collector electrode of (2), and power switch tube Q₂Collector and diode D₁Is connected with the cathode of the power switch tube Q₃Collector electrode of (2), and power switch tube Q₄Collector and diode D₃Is connected with the cathode of the power switch tube Q₅Collector electrode of (2), and power switch tube Q₆Collector and diode D₅The cathodes of the two electrodes are connected; power switch tube Q₂Emitter and diode D₂Is connected with the anode of the power switch tube Q₄Emitter and diode D₄Is connected with the anode of the power switch tube Q₆Emitter and diode D₆The anodes of the anode groups are connected; diode D₂Cathode of (2), diode D₄Cathode of (2), diode D₆The cathode of the energy storage freewheeling circuit is connected with the first end of the energy storage freewheeling circuit; diode D₁Anode of (2), diode D₃Anode of (2), diode D₅Is connected with the second end of the energy storage freewheeling circuit;

the inverter circuit comprises a power switch tube Q₁' power switch tube Q₂' power switch tube Q₃' power switch tube Q₄' power switch tube Q₅' power switch tube Q₆', diode D₁', diode D₂', diode D₃', diode D₄', diode D₅' AND diode D₆', diode D₁' cathode, diode D₃' cathode, diode D₅' the cathode of the power amplifier is connected with the first end of the energy storage follow current circuit; diode D₁' Anode and power switch tube Q₁' emitter-connected, diode D₃' Anode and power switch tube Q₃' emitter-connected, diode D₅' Anode and power switch tube Q₅The emitters of' are connected; power switch tube Q₁' collector and diode D₂' the cathode of the power switch tube Q is connected₃' collector and diode D₄' the cathode of the power switch tube Q is connected₅' collector and diode D₆' connected to the cathode; diode D₂' Anode and power switch tube Q₂' emitter-connected, diode D₄' Anode and power switch tube Q₄' emitter-connected, diode D₆' Anode and power switch tube Q₆The emitters of' are connected; diode D₂' cathode, diode D₄' cathode, diode D₆' the cathode of the rectifier is connected to a second terminal of the energy storage freewheeling circuit.

When in use, the power switch tube Q₁Emitter and power switch tube Q₃Emitter and power switch tube Q₅The emitting electrodes of the three-phase three-wire power supply are respectively connected with three phase wires of the three-phase three-wire power supply; power switch tube Q₁' collector and diode D₂The cathode joint of the motor serves as a U-phase joint point of the three-phase motor, and a power switch tube Q₃' collector and diode D₄The cathode joint of the motor serves as a V-phase joint point of the three-phase motor, and a power switch tube Q₅' collector and diode D₆The cathode junction of the' serves as the junction point of the three-phase motor W.

Further, the energy storage freewheeling circuit comprises an inductor L₁Inductance L₁Is the first end of the energy storage freewheeling circuit, and an inductor L₁The other end of (A) isAnd the second end of the energy storage freewheeling circuit.

Further, the power switch tube Q₁Power switch tube Q₂Power switch tube Q₃Power switch tube Q₄Power switch tube Q₅Power switch tube Q₆Power switch tube Q₁' power switch tube Q₂' power switch tube Q₃' power switch tube Q₄' power switch tube Q₅' power switch tube Q₆' MOS tube or IGBT tube respectively.

The control method of the motor driving circuit containing PFC comprises PFC circuit control and inverter circuit control, wherein,

the PFC circuit control comprises the following steps:

dividing a fundamental wave period into twelve sectors according to the mutual relation of three-phase power supply voltages;

secondly, amplitude detection is carried out on the currently input three-phase power supply voltage signal, and the sector and the phase of the three-phase power supply voltage at the current moment are judged;

step three, respectively defining high voltage phase, medium voltage phase and low voltage phase according to the size of the three-phase power supply voltage in each sector: when the amplitude of the medium voltage phase voltage is positive, executing a step four; when the amplitude of the medium voltage phase voltage is negative, executing a fifth step;

conducting the negative power switch tube corresponding to the low voltage all the time, simultaneously conducting PWM control on the positive power switch tube corresponding to the high voltage and the positive power switch tube corresponding to the medium voltage, and closing the other three power switch tubes in the sector all the time;

conducting the positive power switch tube corresponding to the high voltage phase all the time, simultaneously conducting PWM control on the negative power switch tube corresponding to the medium voltage phase and the negative power switch tube corresponding to the low voltage phase, and closing the other three power switch tubes in the sector all the time;

the inverter circuit control comprises the following steps:

step one, amplitude detection is carried out on a current three-phase motor induced voltage signal, and the current three-phase motor induced voltage signal is respectively defined as a high voltage phase, a medium voltage phase and a low voltage phase according to the magnitude of the three-phase motor induced voltage;

step two, calculating three-phase given current of the motor according to a motor control principle, and respectively defining the three-phase given current as a high current phase, a medium current phase and a low current phase according to the magnitude of the three-phase given current (taking the direction of the motor as the positive direction of the current): when the phase current amplitude of the medium current is positive, executing a step three; when the phase current amplitude of the medium current is negative, executing a step four;

step three, the upper bridge arm power switch tube corresponding to the low current phase is always conducted, wherein when the amplitude of the induced voltage of the phase corresponding to the high current is larger than that of the phase corresponding to the medium current, the step five is executed; when the amplitude of the high-current corresponding phase induced voltage is smaller than that of the medium-current corresponding phase induced voltage, executing a sixth step;

step four, the lower bridge arm power switching tube corresponding to the high current phase is always conducted, wherein step seven is executed when the amplitude of the induced voltage of the phase corresponding to the medium current is larger than that of the phase corresponding to the low current; when the amplitude of the induced voltage of the phase corresponding to the medium current is smaller than that of the induced voltage of the phase corresponding to the low current, executing a step eight;

step five, always conducting the lower bridge arm power switching tube corresponding to the high current phase, and performing PWM control on the lower bridge arm power switching tube corresponding to the medium current phase;

step six, always conducting the lower bridge arm power switching tube corresponding to the medium current phase, and performing PWM control on the lower bridge arm power switching tube corresponding to the high current phase;

step seven, conducting the upper bridge arm power switch tube corresponding to the low current phase all the time, and carrying out PWM control on the upper bridge arm power switch tube corresponding to the medium current phase;

and step eight, always conducting the upper bridge arm power switch tube corresponding to the medium current phase, and performing PWM control on the upper bridge arm power switch tube corresponding to the low current phase.

Further, the PFC circuit controls the current of the inductor L1 to be equal to the maximum term of the absolute value of the given current of the three phases of the motor.

The invention has the beneficial effects that: the motor driving circuit containing PFC can be suitable for motors with different powers, realizes soft start, improves efficiency, and has the advantages of high power factor, low current harmonic content, high efficiency and the like.

Drawings

Fig. 1 is a schematic diagram of a motor driving circuit including a PFC according to an embodiment of the present invention.

FIGS. 2(a) - (c) show the voltage U at the network_a>U_b>0>U_cIn a typical control mode, the motor driving circuit including the PFC according to an embodiment of the present invention implements a current loop mode of full-control rectification.

FIGS. 3(a) - (b) show the reference current i at the motor_v>0>i_u>i_wInduced voltage U of motor_v>U_u>0>U_wIn a typical control mode, the motor driving circuit including the PFC according to an embodiment of the present invention implements an inverted current loop mode.

The reference signs explain: 100, PFC circuit, 200, energy storage freewheeling circuit, 300, inverter circuit.

Detailed Description

In order that the invention may be more fully understood, reference will now be made to the following description. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Referring to fig. 1, a motor driving circuit with PFC according to a preferred embodiment of the present invention includes a PFC circuit 100, an energy storage freewheeling circuit 200 and an inverter circuit 300. The PFC circuit 100 includes six power switching transistors Q₁～Q₆And six diodes D₁～D₆(ii) a The energy storage freewheeling circuit 200 includes an inductor L₁(ii) a The inverter circuit 300 includes six power switching transistors Q₁’～Q₆' with six diodes D₁’～D₆’。

Three powers of PFC circuit 100Switch tube Q₁、Q₃、Q₅The emitting electrodes of the three-phase three-wire power supply are respectively connected with three phase wires of the three-phase three-wire power supply; three power switch transistors Q₂、Q₄、Q₆Respectively with three diodes D₂、D₄、D₆Is connected with the anode of the three diodes D respectively₁、D₃、D₅The cathodes of the two electrodes are connected; three diodes D₂、D₄、D₆Is connected as the output anode of the PFC circuit 100; three diodes D₁、D₃、D₅Is connected as the output cathode of PFC circuit 100.

Power switch tube Q of PFC circuit 100₁Is connected to the diode D at the same time₁Cathode and power switch tube Q₂A collector electrode of (a); power switch tube Q₃Is connected to the diode D at the same time₃Cathode and power switch tube Q₄A collector electrode of (a); power switch tube Q₅Is connected to the diode D at the same time₅Cathode and power switch tube Q₆The collector electrode of (1).

Inductor L₁Are respectively connected with the positive output terminal of the PFC circuit 100 and the negative output terminal of the PFC circuit 100.

Three diodes D of the inverter circuit 300₁’、D₃’、D₅' the cathodes of the two are connected to the positive output of the PFC circuit 100; three power switch transistors Q₂’、Q₄’、Q₆' are connected to the output cathode of the PFC circuit 100. Three diodes D of the inverter circuit 300₁’、D₃’、D₅' the anode is respectively connected with three power switch tubes Q₁’、Q₃’、Q₅The emitters of' are connected; three power switch transistors Q₂’、Q₄’、Q₆' the emitters are respectively connected with three diodes D₂’、D₄’、D₆The anodes of' are connected.

Power switch tube Q of inverter circuit 300₁' collector and diode D₂The cathode of' is connected asA three-phase motor U is connected to a point; rate switching tube Q₃' collector and diode D₄The cathode of the motor is connected to be used as a connecting point of a three-phase motor V; power switch tube Q₅' collector and diode D₆The cathode of the' is connected as the point of attachment of the three-phase machine W.

For simplicity of analysis, the three-phase grid voltage is considered to be symmetrical, and for other grid voltage situations, a person skilled in the art can understand a control mode of the three-phase controllable rectifying circuit in the embodiment. And PWM modulation is carried out on the power switch tube corresponding to the minimum and the middle of the absolute value of the three-phase voltage, wherein the power switch tube corresponding to the maximum absolute value of the three-phase voltage is in a normally-on state. Because of three-phase symmetry, ia + ib + ic is 0, and the absolute value of the phase current with different sign is equal to the sum of the absolute values of the phase currents with the same sign.

During operation, the power switch tube Q is utilized₁～Q₆To implement PFC with U_a>U_b>0>U_cFor example analysis, when the a-phase current and the b-phase current flow out of the power grid, and the c-phase current flows into the power grid, the power switch tube Q₂、Q₄High frequency PWM modulation, power switch tube Q₅Normally-on, power switch tube Q₁、Q₃、Q₆Off when Q is₅And Q₂When on, the PFC circuit current flows as shown in FIG. 2(a), when Q is₅And Q₄When on, the PFC circuit current flows as shown in FIG. 2(b), when Q is₅And Q₄When both are off, no current flows through the PFC circuit. The rest of the cases are analyzed in the same way.

When in work, the power switch tube Q modulated by high frequency in PFC circuit is utilized₁～Q₆The current of the inductor L1 is controlled to be a direct current.

During operation, the power switch tube Q is utilized₁’～Q₆' to realize motor control with motor reference current i_v>0>i_u>i_wFor example analysis, at the moment, u-phase and w-phase currents flow out of the motor, v-phase current flows into the motor, and the power switch tube Q₄' Normal open, when the motor induces a voltage U_u>U_wTime, power switch tube Q₁' high frequency PWM modulation, power switch tube Q₂’、Q₃’、Q₆Off when the power switch tube Q₁When the current flows in the inverter circuit, Q is shown in FIG. 3(b)₁During the on period, turn on Q₅', the current path is not changed; when power switch tube Q₁Off and inverter circuit current flows as shown in fig. 3 (a). When the motor induces voltage U_w>U_uTime, power switch tube Q₅' high frequency PWM modulation, power switch tube Q₂’、Q₃’、Q₆Off when the power switch tube Q₅When the current flows in the inverter circuit, Q is shown in FIG. 3(a)₅During the on period, turn on Q₁', the current path is not changed; when power switch tube Q₅Off and inverter circuit current flows as shown in fig. 3 (b). The rest of the cases are analyzed in the same way.

In this embodiment, the PFC circuit 100 is controlled to keep the three-phase current and the grid voltage in the same phase, so that the system has a high power factor and low harmonic content; and meanwhile, the duty ratio of the PFC circuit 100 is controlled to realize the current control of the inductor L1, and the inductor L1 supplies current to the inverter circuit, so that the system is suitable for motors with different power levels, and the soft start of the motor can be realized, thereby avoiding the overlarge start current of the motor.

The above-mentioned embodiments only express one embodiment of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.