CN215956302U - Motor overvoltage suppression circuit - Google Patents
Motor overvoltage suppression circuit Download PDFInfo
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- CN215956302U CN215956302U CN202121773849.4U CN202121773849U CN215956302U CN 215956302 U CN215956302 U CN 215956302U CN 202121773849 U CN202121773849 U CN 202121773849U CN 215956302 U CN215956302 U CN 215956302U
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- 230000001629 suppression Effects 0.000 title claims abstract description 125
- 230000008859 change Effects 0.000 claims abstract description 19
- 238000000034 method Methods 0.000 claims abstract description 13
- 230000008569 process Effects 0.000 claims abstract description 11
- 230000033228 biological regulation Effects 0.000 claims abstract description 6
- 239000003990 capacitor Substances 0.000 claims description 134
- 230000008878 coupling Effects 0.000 claims description 50
- 238000010168 coupling process Methods 0.000 claims description 50
- 238000005859 coupling reaction Methods 0.000 claims description 50
- 238000001914 filtration Methods 0.000 claims description 26
- 230000007704 transition Effects 0.000 claims description 7
- 238000011084 recovery Methods 0.000 claims description 5
- 238000010521 absorption reaction Methods 0.000 description 22
- 230000009467 reduction Effects 0.000 description 6
- 230000032683 aging Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 238000009413 insulation Methods 0.000 description 5
- 238000004804 winding Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 3
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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
- H02M1/32—Means for protecting converters other than automatic disconnection
- H02M1/34—Snubber circuits
- H02M1/346—Passive non-dissipative snubbers
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/08—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors
- H02H7/09—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors against over-voltage; against reduction of voltage; against phase interruption
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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
- H02M1/12—Arrangements for reducing harmonics from ac input or output
- H02M1/126—Arrangements for reducing harmonics from ac input or output using passive filters
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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
- H02M1/32—Means for protecting converters other than automatic disconnection
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
- H02P29/02—Providing protection against overload without automatic interruption of supply
- H02P29/024—Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load
- H02P29/0241—Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load the fault being an overvoltage
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Inverter Devices (AREA)
- Control Of Ac Motors In General (AREA)
Abstract
The utility model provides a motor overvoltage suppression circuit, comprising: the voltage fluctuation suppression module is connected with the frequency converter, and the voltage clamping module is respectively connected with the voltage fluctuation suppression module and the motor; when the frequency converter outputs a first control voltage in an alternating current form for controlling the speed regulation of the motor to the voltage fluctuation suppression module, the voltage fluctuation suppression module processes the first control voltage to reduce the voltage change rate of the first control voltage, and the voltage clamping module clamps the first control voltage processed by the voltage fluctuation suppression module and a reflected voltage formed by the first control voltage processed by the voltage fluctuation suppression module to obtain a second control voltage output to the motor, so that the value of the second control voltage is smaller than the sum of the first control voltage and the reflected voltage. The motor overvoltage suppression circuit can suppress overvoltage on the motor side.
Description
Technical Field
The utility model relates to the field of motor protection, in particular to a motor overvoltage suppression circuit.
Background
Nowadays, frequency converters are commonly used for speed regulation of motors, and play an important role in using electric power for people. In actual working conditions, the frequency converter and a motor driven by the frequency converter often need cable connection, because the output voltage of the frequency converter is generally PWM pulse voltage, the pulse edge has high voltage change rate, when the length of the cable exceeds a certain value, the transmission time of the voltage pulse in a longer cable exceeds half of the pulse rise time, further because of the mismatching of the cable impedance and the motor impedance, higher reflected voltage is generated on the motor side, the voltage peak value of the motor side is increased, overvoltage occurs on the motor side, the overvoltage can cause the speed of insulation aging of a motor winding to be accelerated, and the service life of the motor can be easily reduced or even damaged.
SUMMERY OF THE UTILITY MODEL
The utility model provides a motor overvoltage suppression circuit which can simultaneously suppress overvoltage at the motor side so as to reduce the risk of the motor being shortened in service life and even damaged due to the overvoltage.
The embodiment of the application provides a motor overvoltage suppression circuit, motor overvoltage suppression circuit includes: the voltage fluctuation suppression device comprises a voltage fluctuation suppression module and a voltage clamping module, wherein the voltage fluctuation suppression module is connected with a frequency converter, and the voltage clamping module is respectively connected with the voltage fluctuation suppression module and the motor; when the frequency converter outputs a first control voltage in an alternating current form for controlling the speed regulation of the motor to the voltage fluctuation suppression module, the voltage fluctuation suppression module processes the first control voltage to reduce the voltage change rate of the first control voltage, and the voltage clamping module clamps the first control voltage processed by the voltage fluctuation suppression module and a reflected voltage formed by the first control voltage processed by the voltage fluctuation suppression module to obtain a second control voltage output to the motor, so that the value of the second control voltage is smaller than the sum of the first control voltage and the reflected voltage.
In an alternative embodiment, the voltage ripple suppression module includes three inductors, wherein the three inductors are a first inductor, a second inductor, and a third inductor, respectively, and the voltage clamping module includes a first input terminal, a second input terminal, and a third input terminal; a first end of the first inductor is connected to a first one of the three phase outputs of the frequency converter, a second end of the first inductor is connected to a first input of the voltage clamping module, and a second end of the first inductor is further connected to a first one of the three phase inputs of the motor; a first end of the second inductor is connected with a second phase output of the three phase outputs of the frequency converter, a second end of the second inductor is connected with a second input of the voltage clamping module, and a second end of the second inductor is further connected with a second phase input of the three phase inputs of the motor; a first end of the third inductor is connected to a third one of the three-phase output terminals of the frequency converter, a second end of the third inductor is connected to a third input terminal of the voltage clamping module, and a second end of the third inductor is further connected to a third one of the three-phase input terminals of the motor.
In an alternative embodiment, the voltage clamping module comprises a three-phase full-bridge rectifier circuit.
In an alternative embodiment, the three-phase full-bridge rectifier circuit includes: the three coupling capacitors are respectively a first coupling capacitor, a second coupling capacitor and a third coupling capacitor; the cathode of the first diode, the cathode of the second diode and the cathode of the third diode are all connected with the positive output end of the direct-current bus of the frequency converter; the anode of the fourth diode, the anode of the fifth diode and the anode of the sixth diode are all connected with the negative output end of the direct-current bus of the frequency converter; the anode of the first diode is connected with the cathode of the fourth diode, the anode of the second diode is connected with the cathode of the fifth diode, and the anode of the third diode is connected with the cathode of the sixth diode; the first end of the first coupling capacitor is connected with the second end of the first inductor, and the second end of the first coupling capacitor is connected with the anode of the first diode; a first end of the second coupling capacitor is connected with a second end of the second inductor, and a second end of the second coupling capacitor is connected with an anode of the second diode; a first end of the third coupling capacitor is connected with a second end of a third inductor, and a second end of the third coupling capacitor is connected with an anode of a third diode; wherein a first terminal of the first coupling capacitor is used as a first input terminal of the voltage clamping module, a first terminal of the second coupling capacitor is used as a second input terminal of the voltage clamping module, and a first terminal of the third coupling capacitor is used as a third input terminal of the voltage clamping module.
In an alternative embodiment, the diode is a fast recovery diode.
In an optional embodiment, the motor overvoltage suppression circuit further comprises: the voltage filtering module is connected between the voltage fluctuation suppression module and the voltage clamping module and is used for filtering the first control voltage processed by the voltage fluctuation suppression module; the voltage clamping module clamps the first control voltage processed by the voltage filtering module and forms a reflected voltage according to the first control voltage processed by the voltage filtering module for processing.
In an alternative embodiment, the voltage filtering module comprises: at least three filter capacitors, wherein at least one filter capacitor is connected between the second ends of every two inductors.
In an alternative embodiment, the at least three filter capacitors include a first filter capacitor, a second filter capacitor, and a third filter capacitor, a first end of the first filter capacitor is connected to the second end of the first inductor, a second end of the first filter capacitor is connected to the second end of the second inductor, a first end of the second filter capacitor is connected to the second end of the second inductor, a second end of the second filter capacitor is connected to the second end of the third inductor, a first end of the third filter capacitor is connected to the second end of the third inductor, and a second end of the third filter capacitor is connected to the second end of the first inductor.
In an optional embodiment, the motor overvoltage suppression circuit further comprises: three voltage sinking modules, each of said three voltage sinking modules connected in parallel across one of said three inductors, a different one of said voltage sinking modules connected in parallel across a different one of said inductors; the voltage sink module sinks a spike voltage generated across the inductor at least in part by the first control voltage transition.
In an alternative embodiment, the voltage sinking module comprises: a snubber resistor and a snubber capacitor, the snubber resistor being connected in series with the snubber capacitor, wherein a first end of the snubber resistor is connected with a first end of the inductor, a second end of the snubber resistor is connected with a first end of the snubber capacitor, and a second end of the snubber capacitor is connected with a second end of the inductor.
In the motor overvoltage suppression circuit in this embodiment, since the voltage fluctuation suppression module is connected to the frequency converter, the voltage clamping module is connected to the voltage fluctuation suppression module and the motor, respectively, and when the frequency converter outputs the first control voltage in the form of ac for controlling the speed of the motor to the voltage fluctuation suppression module, the voltage fluctuation suppression module may process the first control voltage to reduce the voltage change rate of the first control voltage, and further, the voltage clamping module may clamp the first control voltage processed by the voltage fluctuation suppression module and the reflected voltage formed by the first control voltage processed by the voltage fluctuation suppression module to obtain the second control voltage output to the motor, and make the value of the second control voltage smaller than the sum of the first control voltage and the reflected voltage, thereby suppressing the overvoltage caused by the reflected voltage at the motor side, therefore, the problem of accelerated speed of insulation aging of the motor winding caused by overvoltage can be effectively solved, and the risks of service life reduction and damage of the motor caused by overvoltage are reduced.
Drawings
The drawings are only for purposes of illustrating and explaining the present application and are not to be construed as limiting the scope of the present application.
Fig. 1 shows a schematic diagram of an alternative motor overvoltage suppression circuit according to an embodiment of the present application.
Fig. 2 is a schematic diagram of an alternative motor overvoltage suppression circuit according to an embodiment of the present application.
Fig. 3 shows a schematic diagram of another alternative motor overvoltage suppression circuit according to an embodiment of the present application.
Fig. 4 is a schematic circuit diagram of another alternative motor overvoltage suppression circuit according to an embodiment of the present application.
Reference numerals:
10. a voltage fluctuation suppression module; 20. a voltage clamping module; 30. a frequency converter; 40. a motor; 50. a voltage filtering module;
l1, a first inductor; l2, second inductor; l3, third inductor;
c1, a first coupling capacitor; c2, a first coupling capacitor; c3, a first coupling capacitor;
c4, a first filter capacitor; c5, a first filter capacitor; c6, a first filter capacitor;
c7, a first absorption capacitor; c8, a first absorption capacitor; c9, a first absorption capacitor;
r1, a first sinking resistor; r2, a first sinking resistor; r3, a first sinking resistor;
d1, a first diode; d2, a second diode; d3, a third diode; d4, a fourth diode; d5, a fifth diode; d6, a sixth diode;
u1, a first phase output end of three-phase output ends of the frequency converter;
v1, a second phase output end of three phase output ends of the frequency converter;
w1, a third phase output end of the three phase output ends of the frequency converter;
u2, a first phase input of three phase inputs of the motor;
v2, a second phase input of the three phase inputs of the motor;
w2, a third one of the three phase inputs of the motor;
the positive output end of a DC bus of the DCP and the frequency converter; DCN, negative output terminal of DC bus of the frequency converter.
Detailed Description
In order to make those skilled in the art better understand the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, but not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application shall fall within the scope of the protection of the embodiments in the present application.
The converter is often used for the speed governing of motor, in operating condition, need cable junction between converter and its driven motor often, because converter output voltage generally is PWM pulse voltage, there is very high voltage rate of change in its pulse border department, when the length of cable exceeds a definite value, the transmission time of voltage pulse in longer cable exceeds half of pulse rise time, further because the unmatched nature of cable impedance and motor impedance, will produce higher reflection voltage at the motor side, the voltage peak value of motor side consequently risees, therefore overvoltage appears at the motor side, this overvoltage will lead to motor winding insulation ageing's speed to accelerate, make motor life reduction even damage easily.
Referring to fig. 1 to 4, the present embodiment provides a motor overvoltage suppression circuit, including: the voltage fluctuation suppression device comprises a voltage fluctuation suppression module 10 and a voltage clamping module 20, wherein the voltage fluctuation suppression module 10 is connected with a frequency converter 30, and the voltage clamping module 20 is respectively connected with the voltage fluctuation suppression module 10 and the motor 40; when the frequency converter 30 outputs a first control voltage in an ac form for controlling the speed of the motor 40 to the voltage fluctuation suppression module 10, the voltage fluctuation suppression module 10 processes the first control voltage to reduce the voltage change rate of the first control voltage, and the voltage clamping module 20 clamps the first control voltage processed by the voltage fluctuation suppression module 10 and a reflected voltage formed by the first control voltage processed by the voltage fluctuation suppression module 10 to obtain a second control voltage output to the motor 40, so that the value of the second control voltage is smaller than the sum of the first control voltage and the reflected voltage.
In the motor overvoltage suppression circuit in the embodiment, the voltage fluctuation suppression module 10 is connected to the frequency converter 30, the voltage clamping module 20 is connected to the voltage fluctuation suppression module 10 and the motor, respectively, and when the frequency converter outputs a first control voltage in an alternating current form for controlling the speed of the motor to the voltage fluctuation suppression module 10, the voltage fluctuation suppression module 10 may process the first control voltage to reduce the voltage change rate of the first control voltage, further, the voltage clamping module 20 may clamp the first control voltage processed by the voltage fluctuation suppression module 10 and a reflected voltage formed by the first control voltage processed by the voltage fluctuation suppression module 10 to obtain a second control voltage output to the motor 40, and make the value of the second control voltage smaller than the sum of the first control voltage and the reflected voltage, so that the overvoltage caused by the reflected voltage on the motor side is suppressed, therefore, the problem of accelerated speed of insulation aging of the motor winding caused by overvoltage can be effectively solved, and the risks of service life reduction and damage of the motor 40 caused by overvoltage are reduced.
Specifically, the motor 40 in this embodiment is a three-phase motor, the frequency converter 30 also includes three phases, the three-phase output terminals of the frequency converter 30 respectively output first control voltages for controlling the speed regulation of the motor 40 to the three-phase input terminals of the motor 40, the motor overvoltage suppression circuit in this embodiment can respectively process the first control voltages output by the three-phase output terminals of the frequency converter to generate corresponding second control voltages, and finally, the second control voltages having values smaller than the sum of the first control voltages and the reflected voltages are output to the motor 40.
Alternatively, the frequency converter 30 and the motor 40 may be connected by a cable, and after the motor overvoltage suppression circuit in the present embodiment is connected between the frequency converter 30 and the motor 40, at least the voltage clamping module 20 may be connected to the motor 30 by a cable. The length of the cable is not limited in this embodiment, and may be any length, for example, 50 meters, 100 meters, 200 meters, 300 meters, 1000 meters, and the like, and it should be understood that, for a cable with any length, as long as an overvoltage is generated on the motor side of the cable, the cable can play a good role in suppressing the overvoltage of the motor in this embodiment. Preferably, the motor overvoltage suppression circuit in the present embodiment is preferably used in a case where the length of the cable between the inverter 30 and the motor 40 reaches 100 meters or more, and can effectively and sufficiently suppress overvoltage on the motor side.
In this embodiment, the voltage fluctuation suppressing module 10 can reduce the voltage change rate of the first control voltage outputted by the frequency converter, i.e. dv/dt, i.e. the derivative of the voltage with respect to time, which can be used to describe the slope of the pulse voltage at the transition (rising edge or falling edge), because the first control voltage outputted by the frequency converter 30 is a PWM pulse signal and the transition time is almost a moment, the voltage change rate of the first control voltage at the transition is very high. The specific structure of the voltage fluctuation suppression module 10 is not particularly limited in this embodiment, and it is only necessary to be able to effectively suppress and reduce the voltage change rate of the first control voltage output by the frequency converter.
The voltage fluctuation suppression module 10 reduces the voltage change rate of the first control voltage, and further can effectively reduce the magnitude of the reflected voltage generated on the motor side.
In this embodiment, the voltage clamping module 20 may clamp the reflected voltage formed by the first control voltage processed by the voltage fluctuation suppression module 10 and the first control voltage processed by the voltage fluctuation suppression module 10 to obtain the second control voltage output to the motor. In other words, the voltage clamping module 20 can actually clamp the line voltage at the three-phase input end of the motor, so that the value of the second control voltage really output to the motor is smaller than the sum of the first control voltage and the reflected voltage, that is, the influence of the reflected voltage on the motor side is reduced, the overvoltage on the motor side is reduced, and the risk of the motor that the service life is reduced and the motor is damaged due to the overvoltage is reduced.
It should be noted that, in an ideal situation, when the voltage clamping module 20 in the present embodiment clamps the first control voltage processed by the voltage fluctuation suppression module 10 and the reflected voltage formed by the first control voltage processed by the voltage fluctuation suppression module 10, the output second control voltage is equal to the first control voltage, that is: the voltage clamp module 20 may eliminate the reflected voltage so that the motor side overvoltage is sufficiently suppressed. However, in an actual working condition, the ideal condition cannot be achieved generally, and the second control voltage after the actual clamping processing is slightly larger than the first control voltage. In this regard, the present embodiment is not particularly limited.
In one embodiment, referring to fig. 2, the voltage ripple suppression module 10 in the present embodiment includes three inductors, namely a first inductor L1, a second inductor L2 and a third inductor L3, and the voltage clamping module 20 includes a first input terminal, a second input terminal and a third input terminal; a first end of the first inductor L1 is connected to a first one of the three phase outputs of the inverter, U1, a second end of the first inductor L1 is connected to a first input of the voltage clamping module 20, and a second end of the first inductor L1 is further connected to a first one of the three phase inputs of the motor, U2; a first end of the second inductor L2 is connected to a second phase output V1 of the three phase outputs of the inverter, a second end of the second inductor L2 is connected to a second input of the voltage clamping module 20, and a second end of the second inductor L2 is further connected to a second phase input V2 of the three phase inputs of the motor; a first end of the third inductor L3 is connected to a third one of the three phase outputs of the inverter, W1, a second end of the third inductor L3 is connected to a third input of the voltage clamping module 20, and a second end of the third inductor L3 is further connected to a third one of the three phase inputs of the motor, W2.
Due to the electrical characteristics of the inductor, an LC filter loop is easily formed between the inductor and the parasitic capacitance of the cable, and when the first control voltage jumps, the voltage across the inductor does not directly rise to a peak value in a moment but rises relatively slowly, so that in the voltage change rate (i.e., dv/dt), the value of dt is increased under the condition that dv is not changed, and the voltage change rate is effectively reduced.
Therefore, the first inductor L1, the second inductor L2, and the third inductor L3 are connected to the three-phase output end of the inverter 30, and the voltage change rates of the three paths of first control voltages, which are output from the inverter 30 to the motor 40 to control the speed of the motor, are respectively processed, so that the transformation change rate of the first control voltages can be effectively reduced, and the magnitude of the reflected voltage generated on the motor side can be effectively reduced.
Optionally, the three inductors are three inductors in the same three-phase reactor, which makes the stability of the voltage fluctuation suppression module 10 in this embodiment better.
Since the inductor is liable to generate a harmonic current when the frequency converter jumps to the first control voltage outputted by the voltage fluctuation suppression module 10, the harmonic current and the impedance are liable to generate a spike voltage across the inductor, in order to prevent the spike voltage from affecting three inductors, in one embodiment, referring to fig. 4, the motor overvoltage suppression circuit further includes: three voltage sinking modules, each of said three voltage sinking modules connected in parallel across one of said three inductors, a different one of said voltage sinking modules connected in parallel across a different one of said inductors; the voltage sink module sinks a spike voltage generated across the inductor at least in part by the first control voltage transition.
The structure of the voltage absorbing module is not limited in this embodiment, and may be any circuit structure that can absorb spike voltage, for example, in a preferred embodiment, the voltage absorbing module includes: a snubber resistor and a snubber capacitor, the snubber resistor being connected in series with the snubber capacitor, wherein a first end of the snubber resistor is connected with a first end of the inductor, a second end of the snubber resistor is connected with a first end of the snubber capacitor, and a second end of the snubber capacitor is connected with a second end of the inductor.
Specifically, the three voltage absorption modules include three absorption resistors and three absorption capacitors, the three voltage absorption modules are respectively a first voltage absorption module, a second voltage absorption module and a third voltage absorption module, the three absorption resistors are respectively a first absorption resistor R1, a second absorption resistor R2 and a third absorption resistor R3, and the three absorption capacitors are respectively a first absorption capacitor C7, a second absorption capacitor C8 and a third absorption capacitor C9; the first voltage absorbing module comprises a first absorbing resistor R1 and a first absorbing capacitor C7, the first absorbing resistor R1 is connected in series with the first absorbing capacitor C7, a first end of the first absorbing resistor R1 is connected with a first end of a first inductor L1, a second end of the first absorbing resistor R1 is connected with a first end of the first absorbing capacitor C7, and a second end of the first absorbing capacitor C7 is connected with a second end of a first inductor L1; the second voltage absorbing module comprises a second absorbing resistor R2 and a second absorbing capacitor C8, the second absorbing resistor R2 is connected in series with the second absorbing capacitor C8, the first end of the second absorbing resistor R2 is connected with the first end of the second inductor L2, the second end of the second absorbing resistor R2 is connected with the first end of the second absorbing capacitor C8, and the second end of the second absorbing capacitor C8 is connected with the second end of the second inductor L2; the third voltage absorbing module comprises a third absorbing resistor R3 and a third absorbing capacitor C9, the third absorbing resistor R3 is connected in series with the third absorbing capacitor C9, a first end of the third absorbing resistor R3 is connected with a first end of a third inductor L3, a second end of the third absorbing resistor R3 is connected with a first end of the third absorbing capacitor C9, and a second end of the third absorbing capacitor C9 is connected with a second end of a third inductor L3.
Therefore, the voltage absorption module can effectively absorb at least part of the peak voltage generated at the two ends of the inductor due to the jump of the first control voltage, thereby eliminating the influence of the peak voltage on the operation of the inductor, enhancing the effect of the inductor on reducing the voltage change rate of the first control voltage, and further better reducing the size of the reflected voltage generated at the motor side.
In addition, because the voltage absorbing module in the alternative embodiment is provided with the absorbing resistor, although the power loss of the motor overvoltage suppression circuit in the embodiment is increased, the current distortion rate in the circuit can be improved, and the cost of the three-phase reactor can also be reduced due to the existence of the absorbing resistor.
The specific circuit configuration of the voltage clamping module 20 is not limited in this embodiment, and in one embodiment, the voltage clamping module 20 includes a three-phase full-bridge rectifier circuit. Preferably, the three-phase full-bridge rectification circuit is a diode three-phase full-bridge rectification circuit.
Specifically, the three-phase full-bridge rectification circuit includes: six diodes, namely a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5 and a sixth diode D6, and three coupling capacitors, namely a first coupling capacitor C1, a second coupling capacitor C2 and a third coupling capacitor C3; the cathode of the first diode D1, the cathode of the second diode D2 and the cathode of the third diode D3 are all connected with the positive output end DCP of the direct current bus of the frequency converter; the anode of the fourth diode D4, the anode of the fifth diode D5 and the anode of the sixth diode D6 are all connected with the negative output end DCN of the direct current bus of the frequency converter; an anode of the first diode D1 is connected to a cathode of the fourth diode D4, an anode of the second diode D2 is connected to a cathode of the fifth diode D5, and an anode of the third diode D3 is connected to a cathode of the sixth diode D6; a first terminal of the first coupling capacitor C1 is connected with a second terminal of a first inductor L1, a second terminal of the first coupling capacitor C1 is connected with an anode of a first diode D1; a first terminal of the second coupling capacitor C2 is connected with a second terminal of a second inductor L2, a second terminal of the second coupling capacitor C2 is connected with an anode of a second diode D2; a first terminal of the third coupling capacitor C3 is connected with a second terminal of a third inductor L3, a second terminal of the third coupling capacitor C3 is connected with an anode of a third diode D3; wherein a first terminal of the first coupling capacitor C1 is used as a first input terminal of the voltage clamping module 20, a first terminal of the second coupling capacitor C2 is used as a second input terminal of the voltage clamping module 20, and a first terminal of the third coupling capacitor C3 is used as a third input terminal of the voltage clamping module 20.
Preferably, the six diodes are all fast recovery diodes, the switching performance is good, the recovery time is short, and the use requirement can be well met.
In the circuit, three coupling capacitors play a role in blocking direct current and alternating current. Specifically, the operation of the voltage clamping module 20 in this embodiment is described below with reference to fig. 2, and since the operation of the three phases in the circuit is similar, for convenience of description, the operation of the sub-circuit composed of only the first diode D1, the fourth diode D4, and the first coupling capacitor C1 is described.
When the first control voltage processed by the voltage fluctuation suppression module 10 and the first control voltage processed by the voltage fluctuation suppression module 10 form a reflected voltage (for convenience of describing the operation process, the sum of the two voltages is referred to as an overvoltage hereinafter), the reflected voltage and the reflected voltage are subjected to a jump, the first control voltage and the reflected voltage are respectively input into the first coupling capacitor from the first inductor L1 and the two sides of the motor, if the jump is a rising edge and the peak voltage of the PWM is a positive voltage, the overvoltage of the rising edge is input from the anode of the first diode D1 and output from the cathode of the first diode D1 to the positive output end DCP of the dc bus of the frequency converter, so that the forward overvoltage can be absorbed by the dc bus of the frequency converter; if the transition is a falling edge and the peak voltage of the PWM is a negative voltage, the overvoltage of the falling edge is input from the cathode of the fourth diode D4 and output from the anode of the fourth diode D4 to the negative output terminal DCN of the dc bus of the inverter, so that the negative overvoltage can be absorbed by the dc bus of the inverter.
The working process of the sub-circuit composed of the second diode D2, the fifth diode D5 and the second coupling capacitor C2, and the sub-circuit composed of the third diode D3, the sixth diode D6 and the third coupling capacitor C3 may be similar to that described above, and thus, the description is omitted.
Therefore, the voltage clamp module 20 in this embodiment can effectively reduce the influence of the reflected voltage on the motor side, thereby reducing the overvoltage on the motor side and reducing the risk of life reduction and damage of the motor 40 due to the overvoltage.
In one embodiment, referring to fig. 3 and 4, the motor overvoltage suppression circuit further includes: a voltage filtering module 50, wherein the voltage filtering module 50 is connected between the voltage fluctuation suppression module 10 and the voltage clamping module 20, and the voltage filtering module 50 is configured to filter the first control voltage processed by the voltage fluctuation suppression module 10; the voltage clamping module 20 clamps the first control voltage processed by the voltage filtering module 50 and the first control voltage processed by the voltage filtering module 50 to form a reflected voltage.
In this embodiment, the voltage filtering module 50 is used to filter the first control voltage processed by the voltage fluctuation suppression module 10, so that the motor overvoltage suppression circuit in this embodiment has a better filtering performance.
On the basis, the first control voltage is firstly subjected to voltage change rate reduction by the voltage fluctuation suppression module 10, and then is subjected to filtering processing by the voltage filtering module 50, the voltage clamping module 20 clamps the first control voltage and the reflected voltage formed by the first control voltage at this time to obtain a second control voltage output to the motor, so that the value of the second control voltage is smaller than the sum of the first control voltage and the reflected voltage, and the motor overvoltage can obtain a better use effect when the suppression circuit suppresses overvoltage at the motor side.
The specific structure of the voltage filtering module 50 is not limited in this embodiment, and in a preferred embodiment, the voltage filtering module 50 may be specifically configured to reduce the high-frequency differential-mode voltage of the first control voltage processed by the voltage fluctuation suppression module 10.
As an alternative example, the voltage filtering module 50 includes: at least three filter capacitors, wherein at least one filter capacitor is connected between the second ends of every two inductors.
Preferably, the at least three filter capacitors are connected in a delta shape, and three terminals are respectively connected to the second ends of the three inductors. Referring to fig. 4, in particular, the at least three filter capacitors include a first filter capacitor C4, a second filter capacitor C5, and a third filter capacitor C6, a first end of the first filter capacitor C4 is connected to a second end of the first inductor L1, a second end of the first filter capacitor C4 is connected to a second end of the second inductor L2, a first end of the second filter capacitor C5 is connected to a second end of the second inductor L2, a second end of the second filter capacitor C5 is connected to a second end of the third inductor L3, a first end of the third filter capacitor C6 is connected to a second end of the third inductor L3, and a second end of the third filter capacitor C6 is connected to a second end of the first inductor L1. Through the specific circuit structure, the motor overvoltage suppression circuit in the embodiment has better filtering performance, and the high-frequency differential mode voltage of the first control voltage processed by the voltage fluctuation suppression module 10 is reduced to the greatest extent, so that the motor overvoltage suppression circuit can obtain better use effect when suppressing overvoltage at the motor side.
Of course, the circuit structure between the three filter capacitors is only a preferred example, the three filter capacitors may also be connected in a Y-shape, or a resistor may be connected to each filter capacitor on the basis of the circuit structure, and the present embodiment does not limit these possible expansion embodiments.
The motor overvoltage suppression circuit in the embodiment has a remarkable suppression effect on the motor overvoltage, and in addition, the suppression effect on the common-mode voltage is found in actual simulation and actual use.
In the embodiment of the present application, in addition to the specific circuit structures of several preferable motor overvoltage suppression circuits given in the foregoing, a method for correspondingly selecting parameter values of each inductor, capacitor, and resistor is further provided, so that the usability of the motor overvoltage suppression circuit in the embodiment can be better, and the beneficial effects thereof can be fully exerted.
Referring to a circuit configuration diagram of the motor overvoltage suppression circuit in fig. 4, in the present embodiment:
parameter values of the first inductor L1, the second inductor L2, and the third inductor L3 are selected: the method mainly comprises the steps of selecting according to the length of a cable between a frequency converter and a motor and the power of the motor, wherein as an example, for a shielded cable with the length of 100 meters, the value of an inductance value can be selected according to the Uk of 1.5%; for a 300m shielded cable, the value of the inductance value can be chosen as Uk-3%, where Uk is the short-circuit voltage (or impedance voltage, expressed as a percentage of the rated voltage of the motor) of the motor.
Selecting parameter values of the first absorption capacitor C7, the second absorption capacitor C8 and the third absorption capacitor C9: the parameter values of C7-C9 are selected according to the parameter values of L1-L3, preferably, C7 and L1, C8 and L2, and C9 and L3 respectively satisfy the resonance frequency: fr<30 kHz; according to the formula:
the capacitance values of C7, C8 and C9 were obtained.
③ the parameter values of the first snubber resistor R1, the second snubber resistor R2 and the third snubber resistor R3 are selected: after determining L1-L3 and C7-C9, the optimal resistance value is selected by parameter scanning through a simulation tool, for example, the preferred resistance range can be 16-22 omega.
Selecting parameter values of the first filter capacitor C4, the second filter capacitor C5 and the third filter capacitor C6: the capacitors of C4, C5 and C6 can restrain high-frequency differential mode voltage, the values of the capacitors are generally small, and for example, the preferable parameter value range can be between 2.2nF and 10 nF.
Selecting parameter values of the first coupling capacitor C1, the second coupling capacitor C2 and the third coupling capacitor C3: the parameter values of C1-C3 are selected according to the parameter values of L1-L3, preferably, C1 and L1, C2 and L2, and C3 and L3 respectively satisfy the resonance frequency: fr<4 kHz; according to the formula:
the capacitance values of C1, C2 and C3 were obtained.
Sixthly, selecting diodes D1-D6: the fast recovery diodes D1-D6 can be selected according to actual needs.
Therefore, in summary, in the motor overvoltage suppression circuit in the embodiment, since the voltage fluctuation suppression module 10 is connected to the inverter, the voltage clamping module 20 is connected to the voltage fluctuation suppression module 10 and the motor, respectively, and when the inverter outputs the first control voltage in the form of alternating current for controlling the speed of the motor to the voltage fluctuation suppression module 10, the voltage fluctuation suppression module 10 may process the first control voltage to reduce the voltage change rate of the first control voltage, further, the voltage clamping module 20 may clamp the first control voltage processed by the voltage fluctuation suppression module 10 and the reflected voltage formed by the first control voltage processed by the voltage fluctuation suppression module 10 to obtain the second control voltage output to the motor 40, and make the value of the second control voltage smaller than the sum of the first control voltage and the reflected voltage, therefore, the overvoltage caused by the reflected voltage on the motor side is restrained, the problem of accelerated insulation aging speed of the motor winding caused by the overvoltage can be effectively solved, and the risks of service life reduction and damage of the motor 40 caused by the overvoltage are reduced.
As an optional application, the motor overvoltage suppression circuit in this embodiment may be used in a motor control system, where the motor control system may be a system in which a frequency converter controls the speed of a motor, for example, the motor control system may include: the inverter 30, the motor 40 and the aforementioned motor overvoltage suppression circuit, the motor overvoltage suppression circuit is connected between the inverter 30 and the motor 40, the inverter 30 outputs a first control voltage in an alternating current form for controlling the speed regulation of the motor to the motor overvoltage suppression circuit, the motor overvoltage suppression circuit processes the first control voltage to generate a second control voltage output to the motor 40, and the motor 40 regulates the speed in response to the second control voltage. Because the motor overvoltage suppression circuit is connected between the frequency converter 30 and the motor 40 in the motor control system, the overvoltage caused by reflected voltage on the motor side can be suppressed, the service life of the motor cannot be reduced and damaged due to the overvoltage, and the stability of the motor control system is improved.
In addition, the motor overvoltage suppression circuit in the embodiment can also be applied to some motor protection systems, and when the motor overvoltage suppression circuit is applied to the motor protection systems, the damage of overvoltage on the motor side to the motor can be effectively prevented, so that the service life of the motor cannot be reduced and the motor cannot be damaged due to the overvoltage.
It should be understood that expressions like "first", "second", "first" or "second" used in the embodiments of the present application may modify various components regardless of order and/or importance, but these expressions do not limit the corresponding components. The above description is only provided for the purpose of distinguishing components from other components.
Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the embodiments of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.
Claims (10)
1. A motor overvoltage suppression circuit, characterized in that the motor overvoltage suppression circuit comprises: the voltage fluctuation suppression device comprises a voltage fluctuation suppression module (10) and a voltage clamping module (20), wherein the voltage fluctuation suppression module (10) is connected with a frequency converter (30), and the voltage clamping module (20) is respectively connected with the voltage fluctuation suppression module (10) and the motor (40);
when the frequency converter (30) outputs a first control voltage in an alternating current form for controlling the speed regulation of the motor (40) to the voltage fluctuation suppression module (10), the voltage fluctuation suppression module (10) processes the first control voltage to reduce the voltage change rate of the first control voltage, and the voltage clamping module (20) clamps the first control voltage processed by the voltage fluctuation suppression module (10) and a reflected voltage formed by the first control voltage processed by the voltage fluctuation suppression module (10) to obtain a second control voltage output to the motor (40), so that the value of the second control voltage is smaller than the sum of the first control voltage and the reflected voltage.
2. The motor overvoltage suppression circuit according to claim 1, wherein the voltage ripple suppression module (10) includes three inductors, wherein the three inductors are a first inductor (L1), a second inductor (L2), and a third inductor (L3), respectively, and the voltage clamping module (20) includes a first input, a second input, and a third input;
a first end of the first inductor (L1) is connected with a first phase output (U1) of the three phase outputs of the frequency converter, a second end of the first inductor (L1) is connected with a first input of the voltage clamping module (20), and a second end of the first inductor (L1) is further connected with a first phase input (U2) of the three phase inputs of the motor;
a first end of the second inductor (L2) is connected with a second phase output (V1) of the three phase outputs of the frequency converter, a second end of the second inductor (L2) is connected with a second input of the voltage clamping module (20), a second end of the second inductor (L2) is further connected with a second phase input (V2) of the three phase inputs of the motor;
a first end of the third inductor (L3) is connected to a third one of the three phase outputs of the frequency converter (W1), a second end of the third inductor (L3) is connected to a third input of the voltage clamping module (20), and a second end of the third inductor (L3) is further connected to a third one of the three phase inputs of the motor (W2).
3. The motor overvoltage suppression circuit according to claim 2, wherein the voltage clamp module (20) comprises a three-phase full bridge rectifier circuit.
4. The motor overvoltage suppression circuit according to claim 3, wherein said three-phase full-bridge rectification circuit comprises: six diodes, which are a first diode (D1), a second diode (D2), a third diode (D3), a fourth diode (D4), a fifth diode (D5), and a sixth diode (D6), and three coupling capacitors, which are a first coupling capacitor (C1), a second coupling capacitor (C2), and a third coupling capacitor (C3), respectively;
the cathode of the first diode (D1), the cathode of the second diode (D2) and the cathode of the third diode (D3) are all connected with the positive output end (DCP) of the direct current bus of the frequency converter; the anode of the fourth diode (D4), the anode of the fifth diode (D5) and the anode of the sixth diode (D6) are all connected with the negative output end (DCN) of the direct current bus of the frequency converter; an anode of the first diode (D1) is connected to a cathode of the fourth diode (D4), an anode of the second diode (D2) is connected to a cathode of the fifth diode (D5), and an anode of the third diode (D3) is connected to a cathode of the sixth diode (D6);
a first terminal of the first coupling capacitor (C1) is connected with a second terminal of the first inductor (L1), a second terminal of the first coupling capacitor (C1) is connected with an anode of the first diode (D1); a first terminal of the second coupling capacitor (C2) is connected with a second terminal of the second inductor (L2), a second terminal of the second coupling capacitor (C2) is connected with an anode of the second diode (D2); a first terminal of the third coupling capacitor (C3) is connected with a second terminal of the third inductor (L3), a second terminal of the third coupling capacitor (C3) is connected with an anode of the third diode (D3);
wherein a first terminal of the first coupling capacitor (C1) serves as a first input terminal of the voltage clamping module (20), a first terminal of the second coupling capacitor (C2) serves as a second input terminal of the voltage clamping module (20), and a first terminal of the third coupling capacitor (C3) serves as a third input terminal of the voltage clamping module (20).
5. The motor overvoltage suppression circuit according to claim 4, wherein said diode is a fast recovery diode.
6. The motor overvoltage suppression circuit according to claim 2, further comprising: a voltage filtering module (50),
the voltage filtering module (50) is connected between the voltage fluctuation suppression module (10) and the voltage clamping module (20), and the voltage filtering module (50) is used for filtering the first control voltage processed by the voltage fluctuation suppression module (10);
the voltage clamping module (20) clamps the first control voltage processed by the voltage filtering module (50) and the first control voltage processed by the voltage filtering module (50) to form a reflected voltage.
7. The electrical machine overvoltage suppression circuit according to claim 6, wherein the voltage filtering module (50) comprises: at least three filter capacitors, wherein at least one filter capacitor is connected between the second ends of every two inductors.
8. The electrical machine overvoltage suppression circuit according to claim 7, wherein said at least three filter capacitors include a first filter capacitor (C4), a second filter capacitor (C5), and a third filter capacitor (C6),
a first end of the first filter capacitor (C4) is connected with a second end of the first inductor (L1), a second end of the first filter capacitor (C4) is connected with a second end of the second inductor (L2), a first end of the second filter capacitor (C5) is connected with a second end of the second inductor (L2), a second end of the second filter capacitor (C5) is connected with a second end of the third inductor (L3), a first end of the third filter capacitor (C6) is connected with a second end of the third inductor (L3), and a second end of the third filter capacitor (C6) is connected with a second end of the first inductor (L1).
9. The motor overvoltage suppression circuit according to any one of claims 2 to 8, further comprising: three voltage absorbing modules are arranged on the base plate,
each of the three voltage sinking modules is connected in parallel across one of the three inductors, and different ones of the voltage sinking modules are connected in parallel across different ones of the inductors;
the voltage sink module sinks a spike voltage generated across the inductor at least in part by the first control voltage transition.
10. The motor overvoltage suppression circuit of claim 9, wherein said voltage absorbing module comprises: a snubber resistor and a snubber capacitor, and,
the snubber resistor is connected in series with the snubber capacitor, wherein a first end of the snubber resistor is connected to a first end of the inductor, a second end of the snubber resistor is connected to a first end of the snubber capacitor, and a second end of the snubber capacitor is connected to a second end of the inductor.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121773849.4U CN215956302U (en) | 2021-07-30 | 2021-07-30 | Motor overvoltage suppression circuit |
| PCT/EP2022/071405 WO2023006973A1 (en) | 2021-07-30 | 2022-07-29 | Electric machine overvoltage suppression circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121773849.4U CN215956302U (en) | 2021-07-30 | 2021-07-30 | Motor overvoltage suppression circuit |
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| CN215956302U true CN215956302U (en) | 2022-03-04 |
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| CN202121773849.4U Active CN215956302U (en) | 2021-07-30 | 2021-07-30 | Motor overvoltage suppression circuit |
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| WO (1) | WO2023006973A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US5784236A (en) * | 1997-05-22 | 1998-07-21 | Tycor International Corp. | Variable frequency drive reflected wave suppressors |
| KR101448920B1 (en) * | 2013-11-20 | 2014-10-14 | (주)인텍에프에이 | Motor protection apparatus and motor controlling system having the same |
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