A three-phase full-bridge switch timing control method and device based on six-pulse control

Abstract

The present invention discloses a three-phase full-bridge switch timing control method and device based on six-pulse control, which obtains gate drive signal data, processes the gate drive signal data using a phase-locked loop, and determines the amplitude of the three-phase AC voltage signal; controls the switch timing of the three-phase full-bridge according to the amplitude of the three-phase AC voltage signal, obtains the switch timing of the three-phase full-bridge, and determines the initial pulse width center of each switch according to the switch timing state; obtains the dead zone threshold to phase-adjust the initial pulse width center of the switch timing; determines the pulse width adjustment range according to the phase adjustment range; and obtains the adjusted three-phase full-bridge switch timing based on the pulse width adjustment range. It can reduce the current peak value during switch switching, and simultaneously realize the functions of reactive power regulation and DC bus voltage dynamic regulation, without increasing technical costs and reducing technical complexity.

Description

Technical Field

[0001] The present invention relates to the technical field of controlled rectification, and in particular to a three-phase full-bridge switch timing control method and device based on six-pulse control. Background Art

[0002] The four-quadrant high-voltage converter with cascade electrical topology can meet the control requirements of multiple operating scenarios such as steam-electric dual drive, mine hoisting, and special motor test benches. It can feed back the energy of the motor when it is in the generator state to the power grid, thereby realizing rapid braking function, reducing energy consumption and improving the overall efficiency of the system.

[0003] The rectifier side of the four-quadrant high-voltage converter can adopt three methods: controlled rectification with bus as the control target, six-pulse controlled rectification and diode uncontrolled rectification. The controlled rectification with bus voltage as the control target adopts high leakage impedance phase-shifting transformer and combines carrier phase-shifting technology to effectively eliminate the effect of grid-connected switch harmonics. However, there are some difficulties in some specific scenarios, especially in the case of very weak power grid, the converter is prone to resonance problems, the switching frequency is high, the loss is large, and when the load changes drastically, there is a risk of bus control being out of control; diode uncontrolled rectification cannot achieve energy feedback; six-pulse controlled rectification can combine the advantages of controlled rectification with bus as the control target and diode uncontrolled rectification in specific occasions, and can achieve dynamic regulation of DC bus voltage and reduce switching losses. However, six-pulse controlled rectification also has the problem of large current and difficult reactive power regulation when switching. Summary of the invention

[0004] The technical problem to be solved by the present invention is that six-pulse controlled rectifier also has the problems of large current and difficult reactive power regulation during switch switching. The purpose is to provide a three-phase full-bridge switch timing control method and device based on six-pulse control, aiming to reduce the current peak during switch switching, while realizing the functions of reactive power regulation and dynamic regulation of DC bus voltage, reducing the technical complexity without increasing the technical cost, and ensuring the stability of switch switching.

[0005] The present invention is achieved through the following technical solutions:

[0006] The first aspect of the present invention provides a three-phase full-bridge switch timing control method based on six-pulse control, comprising the following specific steps:

[0007] A phase-locked loop is used to process the gate drive signal data to determine the amplitude of the three-phase AC voltage signal;

[0008] The switching timing of the three-phase full bridge is controlled according to the amplitude of the three-phase AC voltage signal. The specific process of the control includes:

[0009] Obtain the switch timing of the three-phase full bridge, and determine the initial pulse width center of each switch according to the switch timing state;

[0010] Obtain the dead zone threshold to perform phase adjustment on the initial pulse width center of the switch timing;

[0011] Determine the pulse width adjustment range according to the phase adjustment range;

[0012] The three-phase full-bridge switching timing is adjusted based on the pulse width adjustment range.

[0013] Furthermore, the switching sequence of the three-phase full bridge includes the upper bridge arm GA1 of the GA phase, the lower bridge arm GA2 of the GA phase, the upper bridge arm GB1 of the GB phase, the lower bridge arm GB2 of the GB phase, the upper bridge arm GC1 of the GC phase, and the lower bridge arm GC2 of the GC phase.

[0014] Further, the determining the amplitude of the three-phase AC voltage signal specifically includes:

[0015] Get the three-phase AC voltage signal u of the three-phase full bridge iGA 、u iGB and u iGC ;

[0016] By controlling the switching states of the IGBT devices GA1, GA2, GB1, GB2, GC1 and GC2, corresponding PWM signals are generated;

[0017] The PWM signal is used to control the output of the inverter to generate a three-phase AC output that matches the three-phase AC voltage signal.

[0018] Furthermore, according to the switch state, the initial pulse width center of the switch timing of the three-phase full bridge is obtained, which specifically includes:

[0019] The initial pulse width center of GA1 is 90°, and the initial pulse width center of GA2 is 270°;

[0020] The initial pulse width center of GB1 is 210°, and the initial pulse width center of GB2 is 30°;

[0021] The initial pulse width center of GC1 is 300, and the initial pulse width center of GC2 is 150°.

[0022] Furthermore, obtaining the dead zone threshold specifically includes: setting a phase difference between the upper bridge arm and the lower bridge arm, and determining the dead zone threshold based on the phase difference.

[0023] Furthermore, in order to prevent the tailing effect of the IGBT switching device, a dead zone is added between the upper bridge arms of GA1, GB1 and GC1, and a dead zone is added between the lower bridge arms of GA2, GB2 and GC2, that is, the pulse width adjustment angle is less than 60° to prevent the impact of large current caused by the simultaneous operation of the two switches;

[0024] Dynamically adjust the pulse width to achieve dynamic adjustment of the DC bus voltage, that is, when the bus voltage rises, the adjustment angle of the pulse width adjustment Y is increased, and when the bus voltage decreases, the adjustment angle of the pulse width adjustment Y is reduced;

[0025] The overall three-phase voltage phase is dynamically shifted, that is, the leading or lagging phase is adjusted X adjustment angle to achieve power factor + / -0.95 adjustment.

[0026] Furthermore, according to the pulse width center data after pulse width adjustment, the opening time of the switch timing of the entire three-phase full-bridge is moved forward to obtain the adjusted three-phase full-bridge switch timing.

[0027] A second aspect of the present invention provides a three-phase full-bridge switch timing control device based on six-pulse control, comprising:

[0028] The phase-locked loop module uses a phase-locked loop to process the gate drive signal data and determine the amplitude of the three-phase AC voltage signal;

[0029] A switch timing control module is used to obtain the switch timing of the three-phase full bridge and determine the initial pulse width center of each switch according to the switch timing state;

[0030] A dead zone control module is used to obtain a dead zone threshold to perform phase adjustment on the initial pulse width center of the switch timing;

[0031] The pulse width adjustment module is used to determine the pulse width adjustment range according to the phase adjustment range, and obtain the adjusted three-phase full-bridge switch timing based on the pulse width adjustment range.

[0032] Furthermore, the phase-locked loop module includes a phase detector and a phase-locked loop.

[0033] Furthermore, the pulse width modulation module includes a voltage monitor and a comparator.

[0034] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0035] The switching frequency of the present invention is 50Hz, the switching loss is low, the system efficiency is high, which is basically close to the two-quadrant product, and at the same time has the reactive power compensation capability, realizing the control of the grid-side power factor and the stability control of the bus voltage;

[0036] The present invention effectively suppresses the peak value of pulse impact current, and combines the carrier phase shifting technology of the grid-connected transformer to effectively eliminate grid-connected switch harmonics. It has obvious advantages in application occasions such as weak power grids and has wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0038] Figure 1 is a control method in an embodiment of the present invention;

[0039] Figure 2 Schematic diagram of the switching sequence of the three-phase full-bridge in the embodiment of the present invention;

[0040] Figure 3 is a control device in an embodiment of the present invention;

[0041] Figure 4 1 is a six-pulse simulation result in an embodiment of the present invention (from top to bottom are the power unit three-phase ABC drive pulse signal, the DC bus voltage and the unit A phase current). DETAILED DESCRIPTION

[0042] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0043] As a possible implementation, Figure 1 As shown, this embodiment provides a three-phase full-bridge switch timing control method based on six-pulse control, including the following specific steps: using a phase-locked loop to process gate drive signal data to determine the amplitude of the three-phase AC voltage signal; controlling the switch timing of the three-phase full-bridge according to the amplitude of the three-phase AC voltage signal, and the specific process of the control includes: obtaining the switch timing of the three-phase full-bridge, and determining the initial pulse width center of each switch according to the switch timing state; obtaining the dead zone threshold to phase-adjust the initial pulse width center of the switch timing; determining the pulse width adjustment range according to the phase adjustment range; and obtaining the adjusted three-phase full-bridge switch timing based on the pulse width adjustment range.

[0044] like Figure 2As shown, this embodiment uses a phase-locked loop to complete the determination of the grid voltage angle (position). Among them, the switching timing of the phase full bridge includes the upper bridge arm GA1 of the GA phase, the lower bridge arm GA2 of the GA phase, the upper bridge arm GB1 of the GB phase, the lower bridge arm GB2 of the GB phase, the upper bridge arm GC1 of the GC phase, and the lower bridge arm GC2 of the GC phase. In order to prevent the tailing effect of the IGBT switch device, a dead zone is added between the upper bridge arms of GA1, GB1, and GC1, and a dead zone is added between the lower bridge arms of GA2, GB2, and GC2, that is, the Y adjustment angle is less than 60° to prevent the impact of large current caused by the simultaneous operation of two switches. Therefore, it is necessary to dynamically adjust the pulse width to realize the dynamic adjustment of the DC bus voltage, that is, when the bus voltage rises, the Y adjustment angle is increased, and when the bus voltage decreases, the Y adjustment angle is reduced. During the adjustment, the three-phase voltage phase is dynamically shifted as a whole, that is, the X adjustment angle is advanced or lagged, to achieve the adjustment of the power factor + / -0.95.

[0045] In some possible implementations, determining the amplitude of the three-phase AC voltage signal specifically includes:

[0046] Get the three-phase AC voltage signal u of the three-phase full bridge iGA 、u iGB and u iGC ;

[0047] By controlling the switching states of the IGBT devices GA1, GA2, GB1, GB2, GC1 and GC2, corresponding PWM signals are generated;

[0048] The PWM signal is used to control the output of the inverter to generate a three-phase AC output that matches the three-phase AC voltage signal.

[0049] In some possible implementations, the switch timing state specifically includes:

[0050] In some possible implementations, obtaining the initial pulse width center of the switching timing of the three-phase full-bridge according to the switching state specifically includes:

[0051] The initial pulse width center of GA1 is 90°, and the initial pulse width center of GA2 is 270°;

[0052] The initial pulse width center of GB1 is 210°, and the initial pulse width center of GB2 is 30°;

[0053] The initial pulse width center of GC1 is 300, and the initial pulse width center of GC2 is 150°.

[0054] In some possible implementations, obtaining the dead zone threshold specifically includes: setting a phase difference between the upper bridge arm and the lower bridge arm, and determining the dead zone threshold based on the phase difference.

[0055] In some possible implementations, a), to prevent the tailing effect of the IGBT switch device, a dead zone is added between the upper bridge arms of GA1, GB1, and GC1, and a dead zone is added between the lower bridge arms of GA2, GB2, and GC2, that is, the Y adjustment angle is less than 60°, so as to prevent the impact of large current caused by the simultaneous operation of the two switches;

[0056] b) Dynamically adjust the pulse width to achieve dynamic adjustment of the DC bus voltage, that is, when the bus voltage rises, the adjustment angle of Y is increased, and when the bus voltage decreases, the adjustment angle of Y is reduced;

[0057] c) Dynamically shift the three-phase voltage phase as a whole, that is, advance or lag the X adjustment angle to achieve power factor adjustment of + / -0.95.

[0058] In some possible implementations, the opening time of the switch timing of the entire three-phase full-bridge is shifted forward according to the pulse width center data after pulse width adjustment to obtain the adjusted three-phase full-bridge switch timing.

[0059] The specific adjustment angles are shown in Table 1:

[0060]

[0061] As a possible implementation, Figure 3 As shown, this embodiment provides a three-phase full-bridge switch timing control method based on six-pulse control, including:

[0062] The phase-locked loop module uses a phase-locked loop to process the gate drive signal data and determine the amplitude of the three-phase AC voltage signal;

[0063] A switch timing control module is used to obtain the switch timing of the three-phase full bridge and determine the initial pulse width center of each switch according to the switch timing state;

[0064] A dead zone control module is used to obtain a dead zone threshold to perform phase adjustment on the initial pulse width center of the switch timing;

[0065] The pulse width adjustment module is used to determine the pulse width adjustment range according to the phase adjustment range, and obtain the adjusted three-phase full-bridge switch timing based on the pulse width adjustment range.

[0066] The phase-locked loop module includes a phase detector and a phase-locked loop, and the pulse width adjustment module includes a voltage monitor and a comparator.

[0067] As a possible implementation method, this embodiment provides an experimental example. The four-quadrant high-voltage converter using this embodiment has been applied in many occasions. This embodiment takes a (1500kW) four-quadrant high-voltage converter as an example for explanation. The number of cascades on the rectifier side of this converter is 8, and a total of 24 independent units are completed. The algorithm of each unit is consistent, that is, this simulation only simulates and verifies one of the units. The results of the simulation according to the specific implementation method in the second chapter of this article are as follows Figure 4 As shown, the dead zone between the upper bridge arms of the power units GA1, GB1, and GC1 is 5°, and the dead zone between the lower bridge arms of GA2, GB2, and GC2 is 5°, which prevents the impact of large current caused by the simultaneous operation of two switches. At the same time, the DC bus voltage also presents a stable change. Full power temperature rise test: The ambient temperature is 23°C, the test lasts for two hours, the maximum temperature of the main transformer is 62°C, the maximum temperature of the unit is 40.5°C, the (1500kW) four-quadrant high-voltage converter test power is full power, the input current on the machine side is 87A, the output current on the rectifier side is 83.31A, and the conversion efficiency is: 83.31 / 87.13=95.62%. The test results once again verified:

[0068] a) The switching frequency is 50Hz, the switching loss is low, the system efficiency is high, which is basically close to the two-quadrant product. At the same time, it has the ability of reactive power compensation to achieve the control of grid-side power factor and bus voltage stability control.

[0069] b) It effectively suppresses the peak value of pulse impact current and, combined with the carrier phase shifting technology of the grid-connected transformer, effectively eliminates grid-connected switch harmonics. It has obvious advantages, especially in applications such as weak power grids, and has a wide range of applications.

[0070] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A three-phase full-bridge switch timing control method based on six-pulse control, characterized in that: The specific steps include: A phase-locked loop is used to process the gate drive signal data to determine the amplitude of the three-phase AC voltage signal; The switching timing of the three-phase full bridge is controlled according to the amplitude of the three-phase AC voltage signal. The specific process of the control includes: Obtain the switch timing of the three-phase full bridge, and determine the initial pulse width center of each switch according to the switch timing state; Obtain the dead zone threshold to perform phase adjustment on the initial pulse width center of the switch timing; Determine the pulse width adjustment range according to the phase adjustment range; The three-phase full-bridge switching timing is adjusted based on the pulse width modulation range.

2. The three-phase full-bridge switch timing control method based on six-pulse control according to claim 1 is characterized in that: The switching sequence of the three-phase full bridge includes the upper bridge arm GA1 of the GA phase, the lower bridge arm GA2 of the GA phase, the upper bridge arm GB1 of the GB phase, the lower bridge arm GB2 of the GB phase, the upper bridge arm GC1 of the GC phase, and the lower bridge arm GC2 of the GC phase.

3. The three-phase full-bridge switch timing control method based on six-pulse control according to claim 2 is characterized in that: The step of determining the amplitude of the three-phase AC voltage signal specifically includes: Get the three-phase AC voltage signal u of the three-phase full bridge iGA 、u iGB and u iGC ; By controlling the switching states of the IGBT devices GA1, GA2, GB1, GB2, GC1 and GC2, corresponding PWM signals are generated; The PWM signal is used to control the output of the inverter to generate a three-phase AC output that matches the three-phase AC voltage signal.

4. The three-phase full-bridge switch timing control method based on six-pulse control according to claim 3 is characterized in that: According to the switch state, the initial pulse width center of the switch timing of the three-phase full bridge is obtained, including: The initial pulse width center of GA1 is 90°, and the initial pulse width center of GA2 is 270°; The initial pulse width center of GB1 is 210°, and the initial pulse width center of GB2 is 30°; The initial pulse width center of GC1 is 300, and the initial pulse width center of GC2 is 150°.

5. The three-phase full-bridge switch timing control method based on six-pulse control according to claim 1 or 4, characterized in that: Acquiring the dead zone threshold specifically includes: setting a phase difference between the upper bridge arm and the lower bridge arm, and determining the dead zone threshold based on the phase difference.

6. The three-phase full-bridge switch timing control method based on six-pulse control according to claim 4 is characterized in that: To prevent the tailing effect of the IGBT switching device, a dead zone is added between the upper bridge arms of GA1, GB1 and GC1, and a dead zone is added between the lower bridge arms of GA2, GB2 and GC2, that is, the pulse width adjustment angle is less than 60° to prevent the impact of large current caused by the simultaneous operation of the two switches; Dynamically adjust the pulse width to achieve dynamic adjustment of the DC bus voltage, that is, when the bus voltage rises, the adjustment angle of the pulse width adjustment Y is increased, and when the bus voltage decreases, the adjustment angle of the pulse width adjustment Y is reduced; The overall three-phase voltage phase is dynamically shifted, that is, the leading or lagging phase is adjusted X adjustment angle to achieve power factor + / -0.95 adjustment.

7. The three-phase full-bridge switch timing control method based on six-pulse control according to claim 6 is characterized in that: According to the pulse width center data after pulse width adjustment, the opening time of the switch timing of the entire three-phase full-bridge is moved forward to obtain the adjusted three-phase full-bridge switch timing.

8. A three-phase full-bridge switch timing control device based on six-pulse control, characterized in that: include: The phase-locked loop module obtains gate drive signal data, processes the gate drive signal data using a phase-locked loop, and determines the amplitude of the three-phase AC voltage signal; A switch timing control module is used to obtain the switch timing of the three-phase full bridge and determine the initial pulse width center of each switch according to the switch timing state; A dead zone control module is used to obtain a dead zone threshold to perform phase adjustment on the initial pulse width center of the switch timing; The pulse width adjustment module is used to determine the pulse width adjustment range according to the phase adjustment range, and obtain the adjusted three-phase full-bridge switch timing based on the pulse width adjustment range.

9. The three-phase full-bridge switch timing control device based on six-pulse control according to claim 8, characterized in that: The phase-locked loop module includes a phase detector and a phase-locked loop.

10. The three-phase full-bridge switch timing control device based on six-pulse control according to claim 8, characterized in that: The pulse width modulation module includes a voltage monitor and a comparator.

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