CN210780567U - Two-phase frequency conversion circuit of three-phase motor - Google Patents
Two-phase frequency conversion circuit of three-phase motor Download PDFInfo
- Publication number
- CN210780567U CN210780567U CN201922008459.7U CN201922008459U CN210780567U CN 210780567 U CN210780567 U CN 210780567U CN 201922008459 U CN201922008459 U CN 201922008459U CN 210780567 U CN210780567 U CN 210780567U
- Authority
- CN
- China
- Prior art keywords
- phase
- bridge
- inverter
- motor
- capacitors
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Inverter Devices (AREA)
Abstract
The utility model discloses a two-phase frequency conversion circuit of a three-phase motor, wherein a speed regulation device comprises a rectifier bridge, two capacitors C with the same capacity, an inverter bridge and a controller; the rectifier bridge is used as a rectifying part, the inverter bridge is used as an inverter part, and the wire outlet end of the rectifier bridge is connected with the wire inlet end of the inverter bridge through a direct current bus; two-phase inversion output of the three-phase alternating current respectively corresponds to a U phase and a V phase of the motor, and the middle point of the two capacitors C corresponds to a W phase of the motor; the two capacitors C are connected in series and then connected in parallel at the direct current bus end, and the midpoint of the two capacitors C is used as a reference point to be connected with the C phase of the power supply and the W phase of the variable frequency output. The utility model discloses a power switch device quantity that two-phase control speed adjusting device of three-phase motor adopted saves the third than traditional inverter circuit, has reduced the volume and the weight of converter to the cost is reduced, control method chooses for use unipolar's sine wave pulse width modulation can realize inverter circuit high efficiency work.
Description
Technical Field
The utility model belongs to the technical field of the AC-DC-AC converter, in particular to two-phase control speed adjusting device of three-phase motor.
Background
At present, an ac-dc-ac frequency converter is an effective speed regulating device and technology for an ac motor. The main function of the common ac-dc-ac frequency conversion circuit is to convert the input three-phase ac into dc through the three-phase rectifier bridge of the frequency converter, and to convert the dc into ac through the three-phase inverter bridge of the frequency converter after the capacitor filtering of the middle part.
However, the frequency conversion circuit has the following disadvantages: the rectifier bridge and the inverter bridge adopt more power switching devices, so that the volume and the weight of a frequency conversion circuit are large, and the cost of the frequency converter is high. Therefore, the principle and the defects of the three-phase AC-DC alternating frequency circuit are comprehensively considered, in order to reduce power switching devices in the AC-DC alternating frequency circuit, the two-phase control speed regulating device of the three-phase motor is adopted, the high-efficiency frequency conversion speed regulation of the motor can be realized, and the three-phase AC-DC alternating frequency circuit has high reliability, small volume and low cost.
SUMMERY OF THE UTILITY MODEL
For the more problem of power switching device who solves above-mentioned rectifier bridge and contravariant bridge adoption, the utility model provides a two-phase inverter circuit of three-phase motor. The utility model discloses a power switch device quantity that double-phase inverter circuit of three-phase motor adopted saves the third than traditional inverter circuit, has reduced the volume and the weight of converter to the cost is reduced, control method chooses for use sine wave pulse width modulation can realize inverter circuit high efficiency work.
The utility model adopts the following technical contents:
a two-phase frequency conversion circuit of a three-phase motor comprises a rectifier bridge, two capacitors C with the same capacity, an inverter bridge and a controller;
the rectifier bridge is used as a rectifying part, the inverter bridge is used as an inverter part, and the wire outlet end of the rectifier bridge is connected with the wire inlet end of the inverter bridge through a direct current bus; two-phase inversion output of the three-phase alternating current respectively corresponds to a U phase and a V phase of the motor, and the middle point of the two capacitors C corresponds to a W phase of the motor;
the two capacitors C are connected in series and then connected in parallel at the direct-current bus end, and the midpoint of the two capacitors C is used as a reference point to be connected with the C phase of the power supply and the W phase of the variable-frequency output;
the phase A and the phase B of the input end of the single-phase bridge rectification take the phase C of three-phase alternating current as a reference point, and two input voltages UAC、UBCThe phase difference is 60 degrees; the output end U phase and V phase of the single-phase full-bridge inversion are opposite to the two voltages U of the W phaseUW、UVWAs output voltage, the voltage phase differs by 60 °;
and a voltage sensor is arranged on the side of the direct current bus, detects a voltage signal of the direct current bus, converts the acquired voltage signal into a digital signal through A/D (analog/digital) and feeds the digital signal back to the controller.
The rectifier bridge adopts a single-phase uncontrollable rectifier bridge and is a single-phase uncontrollable rectifier circuit formed by 4 diodes, wherein the diode VD1 and the diode VD2 form a group of upper and lower bridge arms, and the diode VD3 and the diode VD4 form another group of upper and lower bridge arms.
The inverter bridge is a four-leg inverter bridge and is composed of 4 power switching devices connected with freewheeling diodes in parallel, a power switching tube V1 and a power switching tube V2 form a group of upper and lower legs, and a power switching tube V3 and a power switching tube V4 form another group of upper and lower legs.
The power switch tube V1, the power switch tube V2, the power switch tube V3 and the power switch tube V4 are all electrically connected with the controller.
A control method of a two-phase control speed regulating device based on the three-phase motor comprises the following steps:
the controller adopts sinusoidal pulse width modulation control, a sine wave is used as a modulation wave, a triangular wave is used as a carrier wave, and generated PWM signals control four power switching tubes of V1, V2, V3 and V4;
the amplitude of the alternating current fundamental wave voltage output by the inverter unit is controlled by changing the width of the rectangular pulse, and the output frequency of the alternating current fundamental wave voltage is controlled by changing the modulation period, so that the control of the amplitude and the frequency of the voltage is output at the inverter circuit part at the same time.
Further, the method specifically comprises the following steps:
for an inverter bridge in a two-phase control speed regulation device of a three-phase motor, U, V two-phase PWM control shares a triangular carrier UcU, V sinusoidal modulated signal U of two phasesru、UrvThe phase difference is 60 degrees in sequence; the inverter bridge can output U with 60 deg. phase difference by using W phase as referenceUW、UVWThe control rule of U, V two-phase switch tube is the same, when modulating signal UrAnd carrier UcThe intersection point of the three-way valve controls the on-off of the switch tubes V1, V2, V3 and V4;
for U phase, when Uru>UcWhen the voltage is applied, a conducting signal is provided for the switch tube V1, and a switching-off signal is provided for the switch tube V2, so that the voltage between two phases of UW is obtained; when a conducting signal is applied to the switching tube V1, the diode VD5 which is connected in parallel or V1 is conducted in a follow current mode; when a conducting signal is applied to the switching tube V2, the V2 is conducted or the diode VD6 connected in parallel is conducted in a follow current mode;
for the V phase, when Urv>UcWhen the voltage is applied, a conducting signal is provided for the switching tube V3, and a switching signal is provided for the switching tube V4, so that the voltage between two phases of the VW is obtained; when a conducting signal is applied to the switching tube V3, the V3 is conducted or the diode VD7 connected in parallel is conducted in a follow current mode; when a conducting signal is applied to the switching tube V4, the V4 is conducted or the parallel diode VD8 is conducted in a freewheeling mode.
PWM driving signals of the upper bridge arm and the lower bridge arm are complementary, and a section of dead time of turn-off signals of the upper switching tube and the lower switching tube is reserved when the upper switching tube and the lower switching tube are switched on and off.
Compared with the prior art, the utility model discloses following beneficial effect has:
the utility model discloses a two-phase inverter circuit of three-phase motor realizes pressure regulating, frequency modulation, for rectifier circuit to the direct current voltage that C looks for the reference is U + and U-, is equivalent to forming a positive negative power supply of taking the mid point. Compared with the inversion output, the method takes the middle point of the series capacitor (C phase of the alternating current power supply and W phase of the motor) as a reference point, outputs a sine wave with a mutual difference of 60 electrical angles, forms an actual three-phase symmetrical waveform for the motor as the same as the three-phase power supply principle of the power supply, and generates a rotating magnetic field to drive the motor to rotate. The utility model discloses a power switch device quantity that double-phase inverter circuit of three-phase motor adopted saves the third than traditional inverter circuit, has reduced the volume and the weight of converter to the cost is reduced, control method chooses for use sine wave pulse width modulation can realize inverter circuit high efficiency work.
The utility model discloses a control method adopts sinusoidal pulse width modulation technique, and the sine wave is as modulating the wave, and the triangle wave is as the carrier wave, four power switch tubes of PWM control V1, V2, V3, V4 of production. The amplitude of the alternating current fundamental wave voltage output by the inverter unit can be controlled by changing the width of the rectangular pulse, and the output frequency of the inverter unit can be controlled by changing the modulation period, so that the control of the amplitude and the frequency of the voltage can be simultaneously output by the four-bridge arm inverter circuit part, and the requirement of variable frequency speed regulation on the voltage and frequency coordination control is met. The PWM control can eliminate or inhibit low-order harmonic waves, so that the load motor runs under the alternating voltage of a nearly sine wave, the torque pulse is small, and the speed regulation range is wide.
Drawings
FIG. 1 is a two-phase inverter circuit topology diagram of a three-phase motor;
FIG. 2 is a voltage waveform diagram of the positive and negative ends of a DC bus of a two-phase control speed regulating device of a three-phase motor to a reference phase C phase;
FIG. 3 is a voltage waveform diagram of the DC bus positive and negative ends to the reference phase C phase after the DC bus of the two-phase control speed regulating device of the three-phase motor is connected in parallel with two capacitors C with the same capacity;
fig. 4 is a graph of the output voltage waveform of the rectifier bridge of the two-phase control governor of the three-phase motor.
FIG. 5 is a voltage waveform diagram of a DC bus of a two-phase control speed regulating device of a three-phase motor after the DC bus is connected with two capacitors C with the same capacity in parallel;
fig. 6 is a diagram of the output voltage waveform of the inverter bridge of the two-phase control speed regulating device of the three-phase motor relative to the reference phase w (c).
Detailed Description
The technical solution of the present invention is described in further detail below with reference to the accompanying drawings, but the scope of the present invention is not limited to the following description.
As shown in fig. 1, the two-phase control speed adjusting device of the three-phase motor of the present invention comprises a single-phase uncontrollable rectifier bridge, two capacitors C with the same capacity, a four-leg inverter bridge and a controller; the speed regulator adopts a common single-phase uncontrollable rectifier bridge as a rectifying part and a four-bridge-arm inverter bridge as an inverting part, and is different in that two capacitors C with the same capacity are connected in parallel at a direct current bus end, the two capacitors C are connected in series and then connected in parallel at the direct current bus end, and the midpoint of the two capacitors C is used as a reference point to be connected with the C phase of a power supply and the W phase of variable frequency output. The utility model discloses a double-phase contravariant output is corresponding to the U looks and the V looks of motor respectively, and foretell mid point corresponds the W looks of motor. The A phase and the B phase of the input end of the single-phase bridge rectification use the C phase of three-phase alternating current as a reference point, and the two input voltages are UAC、UBCVoltage phase is 60 °; the outlet end of the single-phase uncontrollable rectifier bridge is connected with the inlet end of the four-bridge arm inverter bridge through a direct current bus, and the two capacitors C are connected in series and then connected in parallel on the direct current bus; the output end of the single-phase full-bridge inversion is provided with two voltages U of a U phase and a V phase relative to a W (C) phaseUW、UVWAs output voltage, the voltage phases differ by 60 °. On the whole structure, the circuit structure topology of a rectification part, a middle part capacitor C and an inversion part of a common frequency conversion circuit is reserved.
Further, the rectification circuit and the inverter circuit respectively adopt a single-phase uncontrollable rectification bridge and a four-leg inverter bridge, the C phase of the three-phase alternating current power supply is connected with the W phase of the three-phase alternating current asynchronous motor, and the midpoint O of two capacitors C with the same capacity is connected with the C phase of the three-phase alternating current power supply. The alternating-current voltage of a power grid is converted into direct-current voltage through a two-phase uncontrollable rectifier bridge, the voltage of a direct-current bus is converted into alternating-current voltage with adjustable amplitude, frequency and phase through a four-bridge arm inverter bridge, the alternating-current voltage is supplied to an asynchronous motor in an alternating-current, direct-current and alternating-current frequency conversion mode, and frequency conversion speed regulation, soft start control and the like are carried out.
UAC、UBCThe phase difference is 60 degrees as the input voltage of the single-phase uncontrollable rectifier bridge. When U is turnedACVoltage of>UBCWhen the voltage is applied, the diodes VD1 and VD4 are conducted; when U is turnedACVoltage of<UBCWhen the voltage is applied, the diode VD3 and the diode VD2 are conducted, and the obtained rectified output voltage relative to the reference phase C phase is shown in figure 2; the obtained direct-current voltage passes through two capacitors C with the same capacity and connected with the direct-current bus in parallel, so that a relatively stable direct-current voltage is obtained, and a waveform diagram is shown in fig. 3. Two capacitors C with the same capacity connected in series between the single-phase uncontrollable rectifier bridge and the four-leg inverter bridge have good filtering effect, and when the voltage is alternated, the voltage at two ends cannot be suddenly changed due to the charging and discharging effect of the capacitors, so that the stability of the voltage is ensured. As shown in FIG. 4, two capacitors C with the same capacity are not added, the output voltage of the single-phase bridge rectifier circuit has large pulsation, and when the single-phase bridge rectifier circuit passes through the serial connection part of the two capacitors C with the same capacity, the obtained direct-current voltage UdAs shown in fig. 5, the larger the capacitance of the two capacitors C, the smaller the voltage ripple, and the voltage U on the dc bus is reduceddThe voltage is used as the input voltage of the four-bridge arm inverter circuit.
Furthermore, the four-leg inverter bridge is composed of two phases of a three-phase voltage type inverter circuit, a fully-controlled device is used as a switching device, the basic working mode of the four-leg inverter circuit still adopts a 180-degree conduction mode, the conduction angle of each leg is 180 degrees, the upper arm and the lower arm of the same phase conduct alternately, and the conduction angles of the other two phases relative to a reference phase are different by 60 degrees.
The following analysis of the operation of the four-leg voltage-type inverter circuit, as shown in fig. 6, yields U, V two-phase signals relative to the reference signalOutput voltage U of phase-checking Wuw、Uvw：
For the U phase, when the switch tube V1 is conducted, UuwHas a voltage of Vac，VacI.e. dc bus U+For the voltage of the C phase of the reference point, when the switch tube V2 is conducted, UuwHas a voltage of Vbc，VbcI.e. the voltage of the dc bus U _ to reference point phase C.
For the V phase, when the switch tube V3 is conducted, UvwHas a voltage of Vac,，VacI.e. dc bus U+For the voltage of the C phase of the reference point, when the switch tube V4 is conducted, UvwHas a voltage of Vbc，VbcI.e. the voltage of the dc bus U _ to reference point phase C.
A control method of a two-phase frequency conversion circuit of a three-phase motor is as follows:
a sine pulse width modulation method, namely SPWM control, is adopted, sine waves are selected as modulation waves in the control method, triangular carrier waves are selected as carriers, and isosceles triangular waves are selected as carrier waves, so that the control method has the characteristic of symmetry. The two interact, the intersection point formed in the positive half period is used as the moment point when the switching tube device is turned on, and the intersection point formed in the negative half period is used as the moment point when the switching tube device is turned off, so that the PWM square wave with the sine wave change rule is generated, and the SPWM is called.
For an inverter bridge in a two-phase control speed regulation device of a three-phase motor, U, V two-phase PWM control shares a triangular carrier UcU, V sinusoidal modulated signal U of two phasesru、UrvThe phase difference is 60 degrees in sequence, so that the inverter bridge can output U with the phase difference of 60 degrees by taking the W phase as a reference phaseUW、UVWThe control rule of U, V two-phase switch tube is the same, when modulating signal UrAnd carrier UcThe crossing point of the three-way valve controls the on-off of the switch tubes V1, V2, V3 and V4.
For the U phase, when Uru>UcAt this time, the on signal is applied to the switch tube V1, and the off signal is applied to the switch tube V2, so that the voltage between two phases of UW can be obtained. The driving signals of the switch tube V1 and the switch tube V2 are complementary all the time, when the switch tube V1 is applied with a conducting signal, it is possible toV1 is conducted, and a diode VD5 connected in parallel can be conducted in a follow current mode; when a conducting signal is applied to the switching tube V2, V2 may be conducting, and the diode VD6 connected in parallel may be freewheeling.
For the V phase, when Urv>UcWhen the on signal is applied to the switch tube V3 and the off signal is applied to the switch tube V4, the voltage between two phases of the VW is obtained. The driving signals of the switch tube V3 and the switch tube V4 are complementary all the time, when a conducting signal is applied to the switch tube V3, the switch tube V3 may be conducted, or the parallel diode VD7 may be conducted in a follow current manner; when a conducting signal is applied to the switching tube V4, V4 may be conducting, and the diode VD8 connected in parallel may be freewheeling.
Furthermore, although the PWM driving signals of the upper and lower bridge arms of the same phase are complementary, in practice, in order to prevent the short circuit caused by the direct connection of the upper and lower switching tubes, a small dead time of the turn-off signals of the upper and lower switching tubes is required to be reserved when the on-off of the upper and lower switching tubes are switched.
Although the present invention has been described in connection with the illustrated embodiments, it is not intended to be limited to the specific embodiments shown, which are intended as illustrative and explanatory only and not as restrictive. Those skilled in the art, having the benefit of this disclosure, may effect numerous modifications thereto without departing from the scope of the invention as defined by the claims appended hereto.
The utility model discloses this kind of speed adjusting device will adopt ordinary single-phase uncontrollable rectifier circuit as the rectification part, and the difference is that the mid point that the rectification output has increased series filter capacitance is connected for the reference point C looks and the W looks reference point of three phase machine of power. Four bridge arms (single-phase full-bridge inverter circuit) of a common three-phase voltage type full-bridge inverter circuit are used as an inverter part, and a series electrolytic capacitor circuit is used in the middle part. The utility model discloses a double-phase contravariant output is corresponding to the U looks and the V looks of motor respectively, and foretell mid point corresponds the W looks of motor.
Relative to the rectifying circuit, the direct current voltage taking the C phase as a reference is U + and U-, which is equivalent to forming a positive and negative power supply with a midpoint. Compared with the inversion output, the SPWM wave with the mutual difference of 60 degrees in electrical angle is output by taking the middle point of the series capacitor (C phase of the alternating current power supply and W phase of the motor) as a reference point, and like the three-phase power supply principle of the power supply, the SPWM wave forms an actual three-phase symmetrical waveform for the motor, generates a rotating magnetic field and drives the motor to rotate. The utility model discloses a power switch device quantity that two-phase control speed adjusting device of three-phase motor adopted saves the third than traditional inverter circuit, has reduced the volume and the weight of converter to the cost is reduced, control method chooses for use unipolar's sine wave pulse width modulation can realize inverter circuit high efficiency work.
The embodiments of the present invention are merely exemplary and not intended to limit the scope of the patent, and those skilled in the art can also make modifications to the embodiments without departing from the spirit and scope of the patent.
Claims (5)
1. A two-phase inverter circuit of three-phase motor which characterized in that: the circuit comprises a rectifier bridge, two capacitors C with the same capacity, an inverter bridge and a controller;
the rectifier bridge is used as a rectifying part, the inverter bridge is used as an inverter part, and the wire outlet end of the rectifier bridge is connected with the wire inlet end of the inverter bridge through a direct current bus; two-phase inversion output of the three-phase alternating current respectively corresponds to a U phase and a V phase of the motor, and the middle point of the two capacitors C corresponds to a W phase of the motor;
the two capacitors C are connected in series and then connected in parallel at the direct-current bus end, and the midpoint of the two capacitors C is used as a reference point to be connected with the C phase of the power supply and the W phase of the variable-frequency output;
and a voltage sensor is arranged on the side of the direct current bus, detects a voltage signal of the direct current bus, converts the acquired voltage signal into a digital signal through A/D (analog/digital) and feeds the digital signal back to the controller.
2. The two-phase inverter circuit of a three-phase motor according to claim 1, wherein: the rectifier bridge adopts a single-phase uncontrollable rectifier bridge and is a single-phase uncontrollable rectifier circuit formed by 4 diodes, wherein the diode VD1 and the diode VD2 form a group of upper and lower bridge arms, and the diode VD3 and the diode VD4 form another group of upper and lower bridge arms.
3. The two-phase inverter circuit of a three-phase motor according to claim 1, wherein: the inverter bridge is a four-leg inverter bridge and is composed of 4 power switching devices connected with freewheeling diodes in parallel, a power switching tube V1 and a power switching tube V2 form a group of upper and lower legs, and a power switching tube V3 and a power switching tube V4 form another group of upper and lower legs.
4. The two-phase inverter circuit of a three-phase motor according to claim 3, wherein: the power switch tube V1, the power switch tube V2, the power switch tube V3 and the power switch tube V4 are all electrically connected with the controller.
5. The two-phase inverter circuit of a three-phase motor according to claim 1, wherein: the A phase and the B phase of the input end of the rectifier bridge use the C phase of three-phase alternating current as reference points, and two input voltages UAC、UBCThe phase difference is 60 degrees; the output end of the inverter bridge has two voltages U of U phase and V phase relative to W phaseUW、UVWAs output voltage, the voltage phases differ by 60 °.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922008459.7U CN210780567U (en) | 2019-11-19 | 2019-11-19 | Two-phase frequency conversion circuit of three-phase motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922008459.7U CN210780567U (en) | 2019-11-19 | 2019-11-19 | Two-phase frequency conversion circuit of three-phase motor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN210780567U true CN210780567U (en) | 2020-06-16 |
Family
ID=71038384
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201922008459.7U Active CN210780567U (en) | 2019-11-19 | 2019-11-19 | Two-phase frequency conversion circuit of three-phase motor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN210780567U (en) |
-
2019
- 2019-11-19 CN CN201922008459.7U patent/CN210780567U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP6481621B2 (en) | Power converter and three-phase AC power supply | |
| CN102856916B (en) | Reactive power control method and circuit of single-phase photovoltaic inverter | |
| CN110768540A (en) | Two-phase control speed regulation device and control method of three-phase motor | |
| Shete et al. | Performance of sinusoidal pulse width modulation based three phase inverter | |
| CN112688589A (en) | Single-stage three-phase high-frequency link combined bidirectional AC/DC converter | |
| CN106208775A (en) | Half period three-phase T-shaped three-level current transformer electric capacity neutral-point voltage balance strategy | |
| Ohnuma et al. | A control method for a single-to-three-phase power converter with an active buffer and a charge circuit | |
| Ohnuma et al. | Space vector modulation for a single phase to three phase converter using an active buffer | |
| CN103973137A (en) | Improved space-vector-control three-phase PWM (pulse width modulation) rectifier system and control method thereof | |
| CN113236670A (en) | Magnetic bearing control system and control method thereof and magnetic suspension system | |
| CN210780567U (en) | Two-phase frequency conversion circuit of three-phase motor | |
| CN110034689B (en) | Modulation method of brushless direct current motor system with small capacitor adopted in direct current chain | |
| CN112838769A (en) | Transformer-isolation-free star-connection medium-high voltage variable frequency speed regulation system and control method | |
| CN208386446U (en) | A kind of doube bridge arm ac-dc-ac inverter soft activator | |
| CN107124105A (en) | Improve isolated form three-level PFC converter PF control system and method | |
| CN109347345B (en) | Sine wave inverter | |
| CN104378034B (en) | The operation control system of brushless ac compound rectifier excitation brshless DC motor | |
| CN208241600U (en) | A kind of doube bridge arm ac-dc-ac inverter circuit | |
| CN109004865B (en) | Double-bridge arm AC-DC-AC variable frequency soft starter and control method | |
| CN109038677A (en) | A kind of efficient six switch singles grid-connected converter | |
| CN108512482B (en) | Double-bridge arm AC-DC-AC frequency conversion circuit and control method thereof | |
| CN113965139A (en) | Thyristor and IGBT mixed three-phase motor two-phase frequency conversion control circuit and method thereof | |
| CN107612388A (en) | A kind of power conversion system based on 12 sector SVPWM | |
| CN210041669U (en) | Phase-selecting rectifying device for six-phase power supply | |
| CN212543681U (en) | Independent double-bridge arm variable frequency soft starter |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |