CN113162448B - Three-level converter bus balance control method, device, equipment and medium - Google Patents
Three-level converter bus balance control method, device, equipment and medium Download PDFInfo
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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
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/483—Converters with outputs that each can have more than two voltages levels
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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
- H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/50—Arrangements for eliminating or reducing asymmetry in polyphase networks
Abstract
The invention discloses a control method, a control device, terminal equipment and a computer storage medium for bus balance of a three-level converter, wherein the method is applied to a space vector generator and is used for acquiring the three-phase duty ratio of the three-level converter; respectively synthesizing the three-phase duty ratios into effective three-phase duty ratios according to preset duty ratio thresholds; and generating symmetrical PWM driving pulse signals according to the effective three-phase duty ratio to control the bus balance. In addition, the invention can still control the balance of the three-level converter bus without additionally increasing a hardware circuit and introducing a new control loop so as to control the balance of the three-level converter bus even under the condition of large dynamic fluctuation without additionally increasing the hardware cost of equipment, thereby greatly improving the stability of the whole circuit and further ensuring the operation safety of a power device of the equipment.
Description
Technical Field
The invention relates to the technical field of Power converter System (energy conversion System) frequency converters, in particular to a method and a device for controlling bus balance of a three-level converter, terminal equipment and a computer storage medium.
Background
With the rapid development of new energy technologies, research and development and application of new energy conversion equipment are receiving more and more attention, and among the new energy conversion equipment, a three-level converter is a common circuit topology form. In the daily application of the three-level converter configured in the equipment, if the three-level converter has bus imbalance (generally referred to as current and voltage imbalance), the power of the equipment is unbalanced, so that the protection mechanism of the equipment is triggered by mistake, and the equipment cannot operate normally.
The existing control method for bus balance of the three-level converter is usually carried out by adding a hardware circuit, carrying out periodic compensation by adopting a DUTY compensation factor, introducing a current control loop and the like, however, the existing control methods for bus balance of the three-level converter can increase the complexity and power consumption of an equipment control circuit on one hand, thereby improving the overall cost of the equipment, and on the other hand, the control for bus balance is very limited, and even other reverse influences can be brought to the equipment.
In summary, it is difficult to efficiently control bus balance for a three-level converter without increasing hardware cost of the device.
Disclosure of Invention
The invention mainly aims to provide a method and a device for controlling bus balance of a three-level converter, terminal equipment and a computer storage medium, and aims to solve the technical problem that bus balance control for the three-level converter is difficult to efficiently control the bus balance without additionally increasing the hardware cost of the equipment.
In order to achieve the above object, an embodiment of the present invention provides a method for controlling bus balance of a three-level converter, where the method for controlling bus balance of a three-level converter is applied to a space vector generator, and the method for controlling bus balance of a level converter includes:
acquiring a three-phase duty ratio of the three-level converter;
respectively synthesizing the three-phase duty ratio into effective three-phase duty ratios according to preset duty ratio thresholds;
and generating a symmetrical PWM (Pulse width modulation) driving Pulse signal according to the effective three-phase duty ratio to control bus balance.
Optionally, the preset duty cycle threshold includes: a preset maximum duty cycle threshold and a preset minimum duty cycle threshold.
Optionally, the step of respectively synthesizing the three-phase duty ratios as effective three-phase duty ratios according to a preset duty ratio threshold includes:
detecting whether the three-phase duty ratio is equal to the preset maximum duty ratio threshold value or the preset minimum duty ratio threshold value;
if not, respectively synthesizing the three-phase duty ratios into effective three-phase duty ratios;
and if so, synthesizing the three-phase duty ratio into an effective three-phase duty ratio based on a preset three-phase balance compensation value.
Optionally, the three-phase duty cycle comprises: if not, respectively synthesizing the three-phase duty ratio into an effective three-phase duty ratio, and the method comprises the following steps of:
if the U-phase duty ratio is not equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold, synthesizing the U-phase duty ratio as an effective U-phase duty ratio;
if the V-phase duty ratio is not equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold, synthesizing the V-phase duty ratio as an effective V-phase duty ratio;
and if the W-phase duty ratio is not equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold, synthesizing the W-phase duty ratio into an effective W-phase duty ratio.
Optionally, the preset three-phase balance compensation value includes: presetting a U-phase balance compensation value, a V-phase balance compensation value and a W-phase balance compensation value.
Optionally, if so, synthesizing the three-phase duty ratio to be an effective three-phase duty ratio based on a preset three-phase balance compensation value, including:
if the three-phase duty ratio is equal to the preset maximum duty ratio threshold value, overlapping the U-phase duty ratio in the three-phase duty ratio with the preset U-phase balance compensation value to obtain a first U-phase duty ratio, and synthesizing the first U-phase duty ratio into an effective U-phase duty ratio;
if the three-phase duty ratio is equal to the preset maximum duty ratio threshold value, superposing a V-phase duty ratio in the three-phase duty ratio with the preset V-phase balance compensation value to obtain a first V-phase duty ratio, and synthesizing the first V-phase duty ratio into an effective V-phase duty ratio;
and if the three-phase duty ratio is equal to the preset maximum duty ratio threshold value, overlapping the W-phase duty ratio in the three-phase duty ratio with the preset W-phase balance compensation value to obtain a first W-phase duty ratio, and synthesizing the first W-phase duty ratio into an effective W-phase duty ratio.
Optionally, if so, synthesizing the three-phase duty ratio that is valid based on a preset three-phase balance compensation value, further including:
if the three-phase duty ratio is equal to the preset minimum duty ratio threshold value, subtracting the preset U-phase balance compensation value from the U-phase duty ratio in the three-phase duty ratio to obtain a second U-phase duty ratio, and synthesizing the first U-phase duty ratio into an effective U-phase duty ratio;
if the three-phase duty ratio is equal to the preset minimum duty ratio threshold value, subtracting the preset V-phase balance compensation value from the V-phase duty ratio in the three-phase duty ratio to obtain a second V-phase duty ratio, and synthesizing the first V-phase duty ratio into an effective V-phase duty ratio;
and if the three-phase duty ratio is equal to the preset minimum duty ratio threshold value, subtracting the preset W-phase balance compensation value from the W-phase duty ratio in the three-phase duty ratio to obtain a second W-phase duty ratio, and synthesizing the first W-phase duty ratio into an effective W-phase duty ratio.
In order to achieve the above object, the present invention provides a bus balance control device for a three-level converter, the bus balance control device being applied to a space vector generator, the bus balance control device for a level converter including:
the acquisition module is used for acquiring the three-phase duty ratio of the three-level converter;
the synthesis module is used for respectively synthesizing the three-phase duty ratio into an effective three-phase duty ratio according to a preset duty ratio threshold;
and the control module is used for generating symmetrical PWM driving pulse signals according to the effective three-phase duty ratio so as to control the bus balance.
In addition, to achieve the above object, the present invention also provides a terminal device, including: a memory, a processor, a communication bus, and a control program for bus balancing of a three-level converter stored on the memory,
the communication bus is used for realizing communication connection between the processor and the memory;
the processor is used for executing a control program of the bus balance of the three-level converter so as to realize the following steps:
detecting common parameters of a function page to be generated in each third-party application program of a function module, wherein each third-party application program is an application program embedded into the function module;
acquiring a three-phase duty ratio of the three-level converter;
respectively synthesizing the three-phase duty ratios into effective three-phase duty ratios according to preset duty ratio thresholds;
and generating symmetrical PWM driving pulse signals according to the effective three-phase duty ratio so as to control bus balance.
Further, to achieve the above object, the present invention also provides a computer storage medium storing one or more programs executable by one or more processors for:
acquiring a three-phase duty ratio of the three-level converter;
respectively synthesizing the three-phase duty ratios into effective three-phase duty ratios according to preset duty ratio thresholds;
and generating symmetrical PWM driving pulse signals according to the effective three-phase duty ratio so as to control bus balance.
The invention provides a control method, a control device, terminal equipment and a calculation storage medium for bus balance of a three-level converter, wherein the control method for bus balance of the three-level converter is applied to a space vector generator and is used for acquiring a three-phase duty ratio of the three-level converter; respectively synthesizing the three-phase duty ratios into effective three-phase duty ratios according to preset duty ratio thresholds; and generating symmetrical PWM driving pulse signals according to the effective three-phase duty ratio to control the bus balance.
According to the invention, a space vector generator is improved so that in the control process of bus balance of a three-level converter, the three-phase duty ratio of the three-level converter in a power grid is obtained through the space vector generator, then the three-phase duty ratio is synthesized into a corresponding effective three-phase duty ratio respectively based on a preset duty ratio threshold value, and finally a symmetrical PWM driving pulse signal is generated based on the effective three-phase duty ratio, so that the bus balance of the three-level converter is controlled.
Compared with the existing bus balance control mode, the bus balance control method can realize that the bus balance of the three-level converter can be still controlled without additionally increasing a hardware circuit and introducing a new control loop, and even the bus of the three-level converter can be still kept in balance under the condition of large dynamic fluctuation without additionally increasing the hardware cost of equipment, thereby greatly improving the stability of the whole circuit and further ensuring the operation safety of a power device of the equipment.
Drawings
FIG. 1 is a schematic structural diagram of a hardware operating environment of a computer device according to a method of an embodiment of the present invention;
FIG. 2 is a schematic flow chart illustrating a method for controlling bus balancing of a three-level converter according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of an application circuit involved in an embodiment of a method for controlling bus balance of a three-level converter according to the present invention;
fig. 4 is a schematic view of a current waveform in an application scenario involved in an embodiment of a control method for bus balancing of a three-level converter according to the present invention;
FIG. 5 is a schematic diagram illustrating an application flow involved in an embodiment of a method for controlling bus balance of a three-level converter according to the present invention;
fig. 6 is a functional block diagram of the control device for bus balancing of a three-level converter according to the present invention.
The implementation, functional features and advantages of the present invention will be further described with reference to the accompanying drawings.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The main solution of the embodiment of the invention is as follows: acquiring a three-phase duty ratio of the three-level converter through a space vector generator; respectively synthesizing the three-phase duty ratios into effective three-phase duty ratios according to preset duty ratio thresholds; and generating symmetrical PWM driving pulse signals according to the effective three-phase duty ratio so as to control bus balance.
Due to the rapid development of new energy technologies, research and development and application of new energy conversion equipment are receiving more and more attention, and in the new energy conversion equipment, a three-level converter is a common circuit topology form. In the daily application of the three-level converter configured in the equipment, if the three-level converter has bus imbalance (generally referred to as current and voltage imbalance), the power of the equipment is unbalanced, so that the protection mechanism of the equipment is triggered by mistake, and the equipment cannot operate normally.
The existing control modes for carrying out bus balance on the three-level converter usually adopt modes of additionally arranging a hardware circuit, adopting a DUTY compensation factor to carry out periodic compensation, introducing a current control loop and the like, however, the existing control modes for carrying out bus balance on the three-level converter can increase the complexity and the power consumption of an equipment control circuit on one hand, thereby improving the overall cost of equipment, and on the other hand, the control on the bus balance is very limited, and even other reverse influences can be brought to the equipment.
In summary, it is difficult to efficiently control bus balance for a three-level converter without increasing hardware cost of the device.
According to the solution provided by the invention, in the control process of bus balance for the three-level converter, the space vector generator is improved to obtain the three-phase duty ratio of the three-level converter in the power grid, then the three-phase duty ratio is synthesized into the corresponding effective three-phase duty ratio respectively based on the preset duty ratio threshold, and finally the symmetrical PWM driving pulse signal is generated based on the effective three-phase duty ratio, so that the bus balance of the three-level converter is controlled.
Compared with the existing bus balance control mode, the bus balance control method can realize that the bus balance of the three-level converter can be still controlled without additionally increasing a hardware circuit and introducing a new control loop, thereby not additionally increasing the hardware cost of equipment, even controlling the bus of the three-level converter to keep balance under the condition of large dynamic fluctuation, greatly improving the stability of the whole circuit and further ensuring the operation safety of a power device of the equipment.
As shown in fig. 1, fig. 1 is a schematic device structure diagram of a hardware operating environment of a terminal device according to an embodiment of the present invention.
The terminal equipment of the embodiment of the invention can be equipment such as a PC, a smart phone, a tablet computer, a portable computer and the like.
As shown in fig. 1, the terminal device may include: a space vector generator (not shown), a processor 1001, e.g., a CPU, a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. Wherein a communication bus 1002 is used to enable connective communication between these components. The user interface 1003 may include a Display (Display), an input unit such as a Keyboard (Keyboard), and the optional user interface 1003 may also include a standard wired interface, a wireless interface. The network interface 1004 may optionally include a standard wired interface, a wireless interface (e.g., WI-FI interface). The memory 1005 may be a high-speed RAM memory or a non-volatile memory such as a disk memory. The memory 1005 may alternatively be a storage device separate from the processor 1001.
Those skilled in the art will appreciate that the device architecture shown in fig. 1 does not constitute a limitation of the terminal device, and in other embodiments, the terminal device may include more or fewer components than shown, or some components may be combined, or a different arrangement of components.
As shown in fig. 1, a memory 1005, which is a kind of computer storage medium, may include therein an operating system, a network communication module, a user interface module, and a control program for bus balancing of the three-level converter.
In the terminal device shown in fig. 1, the network interface 1004 is mainly used for connecting a backend server and performing data communication with the backend server; the user interface 1003 is mainly used for connecting a client (user side) and performing data communication with the client; and the processor 1001 may be configured to call a control program for bus balancing of the three-level converter stored in the memory 1005, and perform the following steps:
acquiring a three-phase duty ratio of the three-level converter;
respectively synthesizing the three-phase duty ratios into effective three-phase duty ratios according to preset duty ratio thresholds;
and generating symmetrical PWM driving pulse signals according to the effective three-phase duty ratio so as to control bus balance.
Further, the preset duty cycle threshold includes: a preset maximum duty cycle threshold and a preset minimum duty cycle threshold.
Further, the processor 1001 may be configured to call a control program for bus balancing of the three-level converter stored in the memory 1005, and further perform the following steps:
detecting whether the three-phase duty ratio is equal to the preset maximum duty ratio threshold value or the preset minimum duty ratio threshold value;
if not, respectively synthesizing the three-phase duty ratios into effective three-phase duty ratios;
and if so, synthesizing the three-phase duty ratio into an effective three-phase duty ratio based on a preset three-phase balance compensation value.
Further, the three-phase duty cycle comprises: the U-phase duty ratio, the V-phase duty ratio, and the W-phase duty ratio, and the processor 1001 may be configured to call up a control program for bus balance of the three-level converter stored in the memory 1005, and further perform the following steps:
if the U-phase duty ratio is not equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold, synthesizing the U-phase duty ratio as an effective U-phase duty ratio;
if the V-phase duty ratio is not equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold, synthesizing the V-phase duty ratio as an effective V-phase duty ratio;
and if the W-phase duty ratio is not equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold, synthesizing the W-phase duty ratio into an effective W-phase duty ratio.
Further, the preset three-phase balance compensation value comprises: presetting a U-phase balance compensation value, a V-phase balance compensation value and a W-phase balance compensation value.
Further, the processor 1001 may be configured to call a control program for bus balancing of the three-level converter stored in the memory 1005, and further perform the following steps:
if the three-phase duty ratio is equal to the preset maximum duty ratio threshold value, overlapping the U-phase duty ratio in the three-phase duty ratio with the preset U-phase balance compensation value to obtain a first U-phase duty ratio, and synthesizing the first U-phase duty ratio into an effective U-phase duty ratio;
if the three-phase duty ratio is equal to the preset maximum duty ratio threshold value, superposing the V-phase duty ratio in the three-phase duty ratio with the preset V-phase balance compensation value to obtain a first V-phase duty ratio, and synthesizing the first V-phase duty ratio into an effective V-phase duty ratio;
and if the three-phase duty ratio is equal to the preset maximum duty ratio threshold value, overlapping the W-phase duty ratio in the three-phase duty ratio with the preset W-phase balance compensation value to obtain a first W-phase duty ratio, and synthesizing the first W-phase duty ratio into an effective W-phase duty ratio.
Further, the processor 1001 may be configured to call a control program for bus balancing of the three-level converter stored in the memory 1005, and further perform the following steps:
if the three-phase duty ratio is equal to the preset minimum duty ratio threshold value, subtracting the preset U-phase balance compensation value from the U-phase duty ratio in the three-phase duty ratio to obtain a second U-phase duty ratio, and synthesizing the first U-phase duty ratio into an effective U-phase duty ratio;
if the three-phase duty ratio is equal to the preset minimum duty ratio threshold value, subtracting the preset V-phase balance compensation value from the V-phase duty ratio in the three-phase duty ratio to obtain a second V-phase duty ratio, and synthesizing the first V-phase duty ratio into an effective V-phase duty ratio;
and if the three-phase duty ratio is equal to the preset minimum duty ratio threshold value, subtracting the preset W-phase balance compensation value from the W-phase duty ratio in the three-phase duty ratio to obtain a second W-phase duty ratio, and synthesizing the first W-phase duty ratio into an effective W-phase duty ratio.
The specific embodiment of the computer device related to the method for controlling bus balance of the three-level converter of the present invention is substantially the same as each specific embodiment of the method for controlling bus balance of the three-level converter described below, and therefore, no further description is given herein, and for convenience of description, a terminal device is used instead of the computer device in the following description.
The invention provides a control method for bus balance of a three-level converter.
It should be noted that, the hardware circuit related to the method for controlling bus balance of a three-level converter provided by the present invention may specifically refer to a "simplified T-type three-level hardware circuit diagram" shown in fig. 3. In addition, the current waveform of the space vector generator according to the method for controlling the bus balance of the three-level converter provided by the invention can specifically refer to the current waveform shown in fig. 4. Due to the conventional PWM (Pulse width modulation) wave-sending method, in the V1 region, the U-phase current will add the bus balance control duty, so that when the bus imbalance occurs in the three-phase (U-phase, V-phase and W-phase) power system under large dynamic conditions, the method cannot effectively control the bus balance. Based on this, the control method of the bus balance of the three-level converter provided by the invention comprises the following steps: in the V1 area, bus balance control duty ratio and U phase do not participate in bus unbalance control, and the x bus adjusts the duty ratio and symmetrically sends waves; similarly, in V2 and V3 areas, the W phase does not participate in the unbalanced control of the bus; in V4 and V5 areas, the V phase does not participate in the bus unbalance control. Please refer to the following embodiments of the control method for bus balance of the three-level converter according to the present invention.
Referring to fig. 2, fig. 2 is a schematic flow chart of a first embodiment of a method for controlling bus balance of a three-level converter according to the present invention, in the embodiment, the method for controlling bus balance of a three-level converter includes:
step S100, acquiring a three-phase duty ratio of the three-level converter;
the space vector generator synthesizes a three-phase duty ratio through the grid voltage of the three-level converter based on feedforward control.
It should be noted that, in the present embodiment, the three-phase duty ratio includes: a U-phase duty cycle, a V-phase duty cycle, and a W-phase duty cycle.
Specifically, for example, referring to the application process shown in fig. 5, after the three-level converter is powered on, the space vector generator calculates PID based on the bus balance Duty, performs PARK (PARK)/Clarke (Clarke) inverse transformation, and then synthesizes the voltage of the power grid where the three-level converter is located based on any mature feedforward control system to obtain the three-phase Duty ratio: u-phase duty ratio-Du, V-phase duty ratio-Dv, and W-phase duty ratio-Dw.
Step S200, respectively synthesizing the three-phase duty ratio into effective three-phase duty ratios according to preset duty ratio thresholds;
it should be noted that, in this embodiment, the preset duty ratio threshold is a maximum limit value and a minimum limit value of a three-phase duty ratio required when the three-level converter performs bus balance control in the grid voltage, and similarly, the preset duty ratio threshold may be calculated by the space vector generator based on feed-forward control through the grid voltage where the three-level converter is located.
After the space vector generator synthesizes the three-phase duty ratio based on the feedforward control, the three-phase duty ratio is further compared with a preset duty ratio threshold respectively, and therefore the three-phase duty ratio is synthesized respectively based on the comparison result to obtain the corresponding effective three-phase duty ratio.
And step S300, generating a symmetrical PWM driving pulse signal according to the effective three-phase duty ratio so as to control the bus balance.
The space vector generator generates the generated PWM drive pulse signal after synthesizing the effective three-phase duty ratio, i.e., based on the effective three-phase duty ratio, thereby controlling the three-level converter bus balance.
Further, in a possible embodiment, the preset duty cycle threshold includes: a preset maximum duty cycle threshold and a preset minimum duty cycle threshold. The step S200 may include:
step S201, detecting whether the three-phase duty ratio is equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold;
it should be noted that, in this embodiment, the preset maximum duty ratio threshold is a maximum limit value of a three-phase duty ratio required when the three-level converter performs bus balance control in the power grid voltage, and the preset minimum duty ratio threshold is a minimum limit value of a three-phase duty ratio required when the three-level converter performs bus balance control in the power grid voltage. Specifically, for example, referring to the application process shown in fig. 5, the space vector generator synthesizes voltages of a power grid where the three-level converter is located based on any mature feedforward control system to obtain a three-phase duty ratio, and further calculates a maximum duty ratio threshold of the three-level converter: dmax and minimum duty cycle threshold: dmin is added.
After synthesizing the three-phase duty ratios based on feedforward control, the space vector generator further compares the three-phase duty ratios with preset duty ratio thresholds respectively, so as to detect whether the three-phase duty ratios are respectively equal to a preset maximum duty ratio threshold among the preset duty ratio thresholds or whether the three-phase duty ratios are respectively equal to a preset minimum duty ratio threshold among the preset duty ratio thresholds.
Specifically, for example, the space vector generator synthesizes and obtains the three-phase duty ratio of the three-level converter under the grid voltage: after the U-phase duty ratio-Du, the V-phase duty ratio-Dv, and the W-phase duty ratio-Dw, the U-phase duty ratio-Du, the V-phase duty ratio-Dv, and the W-phase duty ratio-Dw are respectively compared with the maximum duty ratio threshold of the three-level converter obtained by simultaneous calculation: dmax and minimum duty cycle threshold: dmin is compared to detect whether the U-phase duty cycle-Du is equal to the maximum duty cycle threshold: dmax or equal to the minimum duty cycle threshold: dmin, it is also detected whether the V-phase duty cycle-Dv is equal to the maximum duty cycle threshold: dmax or equal to the minimum duty cycle threshold: dmin, and detecting whether the W-phase duty cycle-Dw is equal to a maximum duty cycle threshold: dmax or equal to the minimum duty cycle threshold: dmin is added to the reaction kettle.
Step S202, if not, respectively synthesizing the three-phase duty ratios into effective three-phase duty ratios;
in the process of respectively comparing the three-phase duty ratios with a preset maximum duty ratio threshold value or a preset minimum duty ratio threshold value and detecting whether the three-phase duty ratios are respectively equal to the preset maximum duty ratio threshold value or the preset minimum duty ratio threshold value, if the three-phase duty ratios are detected to be respectively unequal to the preset maximum duty ratio threshold value or respectively unequal to the preset minimum duty ratio threshold value, the space vector generator directly and respectively synthesizes the three-phase duty ratios to obtain corresponding effective three-phase duty ratios.
Further, in a possible embodiment, the step S202 may include:
step S2021, if the U-phase duty ratio is not equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold, synthesizing the U-phase duty ratio as an effective U-phase duty ratio;
the method comprises the steps that a space vector generator compares a U-phase duty ratio in a three-phase duty ratio with a preset maximum duty ratio threshold or a preset minimum duty ratio threshold to detect whether the U-phase duty ratio is equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold, and if the space vector generator detects that the U-phase duty ratio is not equal to the preset maximum duty ratio threshold or is not equal to the preset minimum duty ratio threshold, the space vector generator directly synthesizes the U-phase duty ratio to obtain a corresponding effective U-phase duty ratio.
Specifically, for example, referring to the schematic application flow shown in fig. 5, the space vector generator synthesizes and obtains the three-phase duty ratio of the three-level converter at the grid voltage: u-phase duty ratio-Du, V-phase duty ratio-Dv, and W-phase duty ratio-Dw, and a maximum duty ratio threshold of the three-level converter: dmax and minimum duty cycle threshold: after Dmin, preferentially and respectively connecting the U-phase duty ratio-Du in the three-phase duty ratio with the maximum duty ratio threshold: dmax and the minimum duty cycle threshold: dmin is compared, so that whether the U-phase duty ratio-Du is equal to the maximum duty ratio threshold value is judged: dmax is equal, and when the U-phase duty ratio-Du is judged to be equal to the maximum duty ratio threshold value: when Dmax is not equal, further judging whether the U-phase duty ratio-Du is equal to the minimum duty ratio threshold value: dmin is equal, and thus, upon determining that the U-phase duty cycle-Du is not equal to the maximum duty cycle threshold: dmax is equal to, nor does it correspond to the minimum duty cycle threshold: when Dmin is equal, the space vector generator directly synthesizes the U-phase duty ratio-Du as the effective U-phase duty ratio to generate a symmetrical PWM driving pulse signal to control the bus balance of the three-level converter.
Step S2022, if the V-phase duty ratio is not equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold, synthesizing the V-phase duty ratio as an effective V-phase duty ratio;
when the space vector generator compares a V-phase duty ratio in a three-phase duty ratio with a preset maximum duty ratio threshold or a preset minimum duty ratio threshold to detect whether the V-phase duty ratio is equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold, if the space vector generator detects that the V-phase duty ratio is not equal to the preset maximum duty ratio threshold or is not equal to the preset minimum duty ratio threshold, the space vector generator directly synthesizes the V-phase duty ratio to obtain a corresponding effective V-phase duty ratio.
Specifically, for example, referring to the application flow diagram shown in fig. 5, after the space vector generator synthesizes the effective U-phase duty ratio, the space vector generator further combines the V-phase duty ratio — Dv in the three-phase duty ratio with the maximum duty ratio threshold value: dmax and the minimum duty cycle threshold: dmin is compared, so that whether the V-phase duty ratio-Dv is equal to the maximum duty ratio threshold value is judged: dmax is equal, and when the V-phase duty ratio-Dv is judged to be equal to the maximum duty ratio threshold: when Dmax is not equal, further judging whether the V-phase duty ratio-Dv is equal to the minimum duty ratio threshold value: dmin is equal, so that, upon determining that the V-phase duty cycle-Dv is not equal to the maximum duty cycle threshold value: dmax is equal to, nor does it correspond to the minimum duty cycle threshold: when Dmin is equal, the space vector generator directly synthesizes the V-phase duty ratio-Dv as an effective V-phase duty ratio to generate a symmetrical PWM driving pulse signal to control the bus balance of the three-level converter.
Step S2023, if the W-phase duty ratio is not equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold, synthesizing the W-phase duty ratio as an effective W-phase duty ratio.
The space vector generator compares the W-phase duty ratio in the three-phase duty ratio with a preset maximum duty ratio threshold value or a preset minimum duty ratio threshold value to detect whether the W-phase duty ratio is equal to the preset maximum duty ratio threshold value or the preset minimum duty ratio threshold value, and if the space vector generator detects that the W-phase duty ratio is not equal to the preset maximum duty ratio threshold value or is not equal to the preset minimum duty ratio threshold value, the space vector generator directly synthesizes the W-phase duty ratio to obtain a corresponding effective W-phase duty ratio.
Specifically, for example, referring to the application flow diagram shown in fig. 5, after the space vector generator synthesizes the effective V-phase duty ratio, the space vector generator further respectively connects the W-phase duty ratio — Dw of the three-phase duty ratio with the maximum duty ratio threshold value: dmax and the minimum duty cycle threshold: dmin is compared, so as to judge whether the W-phase duty ratio-Dw is equal to the maximum duty ratio threshold value: dmax is equal, and when the W-phase duty ratio-Dw is judged to be equal to the maximum duty ratio threshold value: when Dmax is not equal, further judging whether the W-phase duty ratio-Dw is equal to the minimum duty ratio threshold value: dmin is equal, so that, upon determining that the W-phase duty cycle — Dw is not equal to the maximum duty cycle threshold: dmax is equal to, nor does it correspond to the minimum duty cycle threshold: when Dmin is equal, the space vector generator directly synthesizes the W-phase duty ratio-Dw as an effective W-phase duty ratio to generate a symmetrical PWM driving pulse signal to control the bus balance of the three-level converter.
Further, in another possible embodiment, the space vector generator may further simultaneously detect whether the U-phase duty ratio-Du, the V-phase duty ratio-Dv, and the W-phase duty ratio-Dw are equal to the preset maximum duty ratio threshold and the preset maximum duty ratio threshold, respectively, instead of sequentially detecting the U-phase duty ratio-Du, the V-phase duty ratio-Dv, and the W-phase duty ratio-Dw, respectively, whether the U-phase duty ratio-Du, the V-phase duty ratio-Dv, and the W-phase duty ratio-Dw are equal to the preset maximum duty ratio threshold and the preset maximum duty ratio threshold.
And step S203, if yes, synthesizing the three-phase duty ratio into an effective three-phase duty ratio based on a preset three-phase balance compensation value.
In the process that the space vector generator respectively compares the three-phase duty ratios with a preset maximum duty ratio threshold value or a preset minimum duty ratio threshold value to detect whether the three-phase duty ratios are respectively equal to the preset maximum duty ratio threshold value or the preset minimum duty ratio threshold value, if the three-phase duty ratios are respectively detected to be respectively equal to the preset maximum duty ratio threshold value or respectively equal to the preset minimum duty ratio threshold value, the space vector generator respectively correspondingly synthesizes the three-phase duty ratios based on preset three-phase balance compensation values to obtain respectively corresponding effective three-phase duty ratios.
It should be noted that, in this embodiment, the preset three-phase balance compensation value includes: the preset U-phase balance compensation value, the preset V-phase balance compensation value and the preset W-phase balance compensation value may be specifically set based on design requirements of practical applications. Further, in a possible embodiment, the step S203 may include:
step S2031, if the three-phase duty ratio is equal to the preset maximum duty ratio threshold, superposing the U-phase duty ratio in the three-phase duty ratio on the preset U-phase balance compensation value to obtain a first U-phase duty ratio, and synthesizing the first U-phase duty ratio into an effective U-phase duty ratio;
the method comprises the steps that when a space vector generator compares a U-phase duty ratio in a three-phase duty ratio with a preset maximum duty ratio threshold or a preset minimum duty ratio threshold to detect whether the U-phase duty ratio is equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold, if the space vector generator detects that the U-phase duty ratio is equal to the preset maximum duty ratio threshold, the space vector generator superimposes the U-phase duty ratio with a preset U-phase balance compensation value, and then synthesizes a first U-phase duty ratio superimposed with the preset U-phase balance compensation value to obtain a corresponding effective U-phase duty ratio.
Specifically, for example, referring to the schematic application flow shown in fig. 5, the space vector generator synthesizes and obtains the three-phase duty ratio of the three-level converter at the grid voltage: u-phase duty ratio-Du, V-phase duty ratio-Dv, and W-phase duty ratio-Dw, and a maximum duty ratio threshold of the three-level converter: dmax and minimum duty cycle threshold: after Dmin, preferentially and respectively connecting the U-phase duty ratio-Du in the three-phase duty ratio with the maximum duty ratio threshold: dmax and the minimum duty cycle threshold: dmin is compared, so that whether the U-phase duty ratio-Du is equal to the maximum duty ratio threshold value is judged: dmax is equal, and when the U-phase duty ratio-Du is judged to be equal to the maximum duty ratio threshold value: when Dmax is equal, the space vector generator superimposes the U-phase duty ratio-Du with a preset U-phase balance compensation value-U-phase compensation bus balance duty, and then synthesizes the first U-phase duty ratio superimposed with the U-phase compensation bus balance duty as an effective U-phase duty ratio to generate a symmetrical PWM driving pulse signal to control the bus balance of the three-level converter.
Step S2032, if the three-phase duty ratio is equal to the preset maximum duty ratio threshold, superposing the V-phase duty ratio in the three-phase duty ratio on the preset V-phase balance compensation value to obtain a first V-phase duty ratio, and synthesizing the first V-phase duty ratio into an effective V-phase duty ratio;
the space vector generator compares a V-phase duty ratio in a three-phase duty ratio with a preset maximum duty ratio threshold value or a preset minimum duty ratio threshold value to detect whether the V-phase duty ratio is equal to the preset maximum duty ratio threshold value or the preset minimum duty ratio threshold value, if the space vector generator detects that the V-phase duty ratio is equal to the preset maximum duty ratio threshold value, the space vector generator superimposes the V-phase duty ratio with a preset V-phase balance compensation value, and then synthesizes a first V-phase duty ratio superimposed with the preset V-phase balance compensation value to obtain a corresponding effective V-phase duty ratio.
Specifically, for example, referring to the application flow diagram shown in fig. 5, after the space vector generator synthesizes the effective U-phase duty ratio, the space vector generator further combines the V-phase duty ratio — Dv in the three-phase duty ratio with the maximum duty ratio threshold value: dmax and the minimum duty cycle threshold: dmin is compared, so that whether the V-phase duty ratio-Dv is equal to the maximum duty ratio threshold value is judged: dmax or minimum duty cycle threshold: dmi is equal, and therefore, when it is determined that the V-phase duty ratio-Dv and the maximum duty ratio threshold value: when Dmax is equal, the space vector generator superimposes the V-phase duty ratio-Dv with a preset V-phase balance compensation value-V-phase compensation bus balance duty, and then synthesizes the first V-phase duty ratio superimposed with the V-phase compensation bus balance duty as an effective V-phase duty ratio for generating a symmetrical PWM driving pulse signal to control the bus balance of the three-level converter.
Step S2033, if the three-phase duty ratio is equal to the preset maximum duty ratio threshold, superposing the W-phase duty ratio in the three-phase duty ratio on the preset W-phase balance compensation value to obtain a first W-phase duty ratio, and synthesizing the first W-phase duty ratio into an effective W-phase duty ratio.
When the space vector generator compares the W-phase duty ratio in the three-phase duty ratio with a preset maximum duty ratio threshold or a preset minimum duty ratio threshold to detect whether the W-phase duty ratio is equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold, if the space vector generator detects that the W-phase duty ratio is equal to the preset maximum duty ratio threshold, the space vector generator superimposes the W-phase duty ratio with a preset W-phase balance compensation value, and then synthesizes the first W-phase duty ratio superimposed with the preset W-phase balance compensation value to obtain a corresponding effective V-phase duty ratio.
Specifically, for example, referring to the application flow diagram shown in fig. 5, after the space vector generator synthesizes the effective V-phase duty ratio, the space vector generator further combines the W-phase duty ratio — Dw of the three-phase duty ratio with the maximum duty ratio threshold value: dmax and the minimum duty cycle threshold: dmin is compared, so as to judge whether the W-phase duty ratio-Dw is equal to the maximum duty ratio threshold value: dmax or minimum duty cycle threshold: dmi is equal, and therefore, when it is determined that the W-phase duty ratio-Dw and the maximum duty ratio threshold value: when Dmax is equal, the space vector generator superimposes the W-phase duty ratio-Dw with a preset W-phase balance compensation value-W-phase compensation bus balance duty, and then synthesizes the first W-phase duty ratio superimposed with the W-phase compensation bus balance duty as an effective W-phase duty ratio to generate a symmetrical PWM driving pulse signal to control the bus balance of the three-level converter.
Further, in a possible embodiment, the step S203 may further include:
step S2034, if the three-phase duty ratio is equal to the preset minimum duty ratio threshold, subtracting the preset U-phase balance compensation value from the U-phase duty ratio in the three-phase duty ratio to obtain a second U-phase duty ratio, and synthesizing the second U-phase duty ratio as an effective U-phase duty ratio;
and if the space vector generator detects that the U-phase duty ratio is equal to the preset minimum duty ratio threshold value, the space vector generator subtracts a preset U-phase balance compensation value from the U-phase duty ratio to obtain a second U-phase duty ratio, and then synthesizes the second U-phase duty ratio to obtain a corresponding effective U-phase duty ratio.
Specifically, for example, referring to the schematic application flow shown in fig. 5, the space vector generator synthesizes and obtains the three-phase duty ratio of the three-level converter at the grid voltage: u-phase duty ratio-Du, V-phase duty ratio-Dv, and W-phase duty ratio-Dw, and a maximum duty ratio threshold of the three-level converter: dmax and minimum duty cycle threshold: after Dmin, preferentially and respectively connecting the U-phase duty ratio-Du in the three-phase duty ratio with the maximum duty ratio threshold: dmax and the minimum duty cycle threshold: dmin is compared, so as to judge whether the U-phase duty ratio-Du is equal to the maximum duty ratio threshold value: dmax or with minimum duty cycle threshold: dmin is equal, and when it is determined that the U-phase duty ratio-Du is equal to the minimum duty ratio threshold: when Dmin is equal, the space vector generator subtracts a preset U-phase balance compensation value-U-phase compensation bus balance duty from the U-phase duty ratio-Du to obtain a second U-phase duty ratio, and then synthesizes and overlaps the second U-phase duty ratio as an effective U-phase duty ratio to generate a symmetrical PWM driving pulse signal to control the bus balance of the three-level converter.
Step S2035, if the three-phase duty ratio is equal to the preset minimum duty ratio threshold value, subtracting the preset V-phase balance compensation value from the V-phase duty ratio in the three-phase duty ratio to obtain a second V-phase duty ratio, and synthesizing the second V-phase duty ratio as an effective V-phase duty ratio;
the space vector generator compares a V-phase duty ratio in a three-phase duty ratio with a preset maximum duty ratio threshold value or a preset minimum duty ratio threshold value to detect whether the V-phase duty ratio is equal to the preset maximum duty ratio threshold value or the preset minimum duty ratio threshold value, if the space vector generator detects that the V-phase duty ratio is equal to the preset minimum duty ratio threshold value, the space vector generator subtracts a preset V-phase balance compensation value from the V-phase duty ratio to obtain a second V-phase duty ratio, and then synthesizes the second V-phase duty ratio to obtain a corresponding effective V-phase duty ratio.
Specifically, for example, referring to the schematic application flow shown in fig. 5, the space vector generator synthesizes and obtains the three-phase duty ratio of the three-level converter at the grid voltage: u-phase duty ratio-Du, V-phase duty ratio-Dv, and W-phase duty ratio-Dw, and a maximum duty threshold value of the three-level converter: dmax and minimum duty cycle threshold: after Dmin, the V-phase duty ratio-Dv among the three-phase duty ratios is also respectively compared with the maximum duty ratio threshold value: dmax and the minimum duty cycle threshold: dmin is compared, so as to judge whether the V-phase duty ratio-Dv is equal to the maximum duty ratio threshold value: dmax or with the minimum duty cycle threshold: dmin is equal, and when it is determined that the V-phase duty ratio-Dv and the minimum duty ratio threshold value are equal: when Dmin is equal, the space vector generator subtracts a preset V-phase balance compensation value-V-phase compensation bus balance duty from the V-phase duty ratio-Dv to obtain a second V-phase duty ratio, and then synthesizes and overlaps the second V-phase duty ratio as an effective V-phase duty ratio to generate a symmetrical PWM driving pulse signal to control the bus balance of the three-level converter.
Step S2036, if the three-phase duty ratio is equal to the preset minimum duty ratio threshold, subtracting the preset W-phase balance compensation value from the W-phase duty ratio in the three-phase duty ratio to obtain a second W-phase duty ratio, and synthesizing the second W-phase duty ratio as an effective W-phase duty ratio.
The space vector generator compares a W-phase duty ratio in a three-phase duty ratio with a preset maximum duty ratio threshold value or a preset minimum duty ratio threshold value to detect whether the W-phase duty ratio is equal to the preset maximum duty ratio threshold value or the preset minimum duty ratio threshold value, if the space vector generator detects that the W-phase duty ratio is equal to the preset minimum duty ratio threshold value, the space vector generator subtracts a preset W-phase balance compensation value from the W-phase duty ratio to obtain a second W-phase duty ratio, and then synthesizes the second W-phase duty ratio to obtain a corresponding effective W-phase duty ratio.
Specifically, for example, referring to the schematic application flow shown in fig. 5, the space vector generator synthesizes and obtains the three-phase duty ratio of the three-level converter at the grid voltage: u-phase duty ratio-Du, V-phase duty ratio-Dv, and W-phase duty ratio-Dw, and a maximum duty ratio threshold of the three-level converter: dmax and minimum duty cycle threshold: after Dmin, the W-phase duty ratio — Dw among the three-phase duty ratios is also respectively compared with the maximum duty ratio threshold: dmax and the minimum duty cycle threshold: dmin is compared, so as to judge whether the W-phase duty ratio-Dw is equal to the maximum duty ratio threshold value: dmax or with the minimum duty cycle threshold: dmin is equal, and when it is determined that the W-phase duty ratio-Dw is equal to the minimum duty ratio threshold: when Dmin is equal, the space vector generator subtracts a preset W-phase balance compensation value-W-phase compensation bus balance duty from the W-phase duty ratio-Dw to obtain a second W-phase duty ratio, and then synthesizes and overlaps the second W-phase duty ratio as an effective W-phase duty ratio to generate a symmetrical PWM driving pulse signal to control the bus balance of the three-level converter.
In the embodiment, the space vector generator synthesizes a three-phase duty ratio through the grid voltage where the three-level converter is located based on feedforward control; after the space vector generator synthesizes the three-phase duty ratio based on feedforward control, the three-phase duty ratio is further compared with a preset duty ratio threshold respectively, and therefore the three-phase duty ratio is synthesized respectively based on comparison results to obtain a corresponding effective three-phase duty ratio; the space vector generator generates the generated PWM drive pulse signal after synthesizing the effective three-phase duty ratio, i.e., based on the effective three-phase duty ratio, thereby controlling the three-level converter bus balance.
According to the invention, a space vector generator is improved so that in the control process of bus balance of a three-level converter, the three-phase duty ratio of the three-level converter in a power grid is obtained through the space vector generator, then the three-phase duty ratio is synthesized into a corresponding effective three-phase duty ratio respectively based on a preset duty ratio threshold value, and finally a symmetrical PWM driving pulse signal is generated based on the effective three-phase duty ratio, so that the bus balance of the three-level converter is controlled.
Compared with the existing bus balance control mode, the bus balance control method can realize that the bus balance of the three-level converter can be still controlled without additionally increasing a hardware circuit and introducing a new control loop, and even the bus of the three-level converter can be still kept in balance under the condition of large dynamic fluctuation without additionally increasing the hardware cost of equipment, thereby greatly improving the stability of the whole circuit and further ensuring the operation safety of a power device of the equipment.
In addition, the present invention also provides a control device for bus balance of the three-level converter, please refer to fig. 6, fig. 6 is a functional module schematic diagram of the control device for bus balance of the three-level converter of the present invention, and the functional module schematic diagram is shown in the figure
The control device for bus balance of the three-level converter is applied to a space vector generator, and comprises:
an obtaining module 101, configured to obtain a three-phase duty ratio of the three-level converter;
the synthesis module 102 is configured to synthesize the three-phase duty ratios into effective three-phase duty ratios according to preset duty ratio thresholds;
and the control module 103 is used for generating a symmetrical PWM driving pulse signal according to the effective three-phase duty ratio so as to control the bus balance.
Optionally, the preset duty cycle threshold includes: a preset maximum duty cycle threshold and a preset minimum duty cycle threshold.
Optionally, the synthesis module 102 comprises:
a detecting unit, configured to detect whether the three-phase duty ratio is equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold;
a first synthesizing unit for respectively synthesizing the three-phase duty ratios into effective three-phase duty ratios;
and the second synthesis unit is used for synthesizing the three-phase duty ratio into an effective three-phase duty ratio based on a preset three-phase balance compensation value.
Optionally, the three-phase duty cycle comprises: u looks duty cycle, V looks duty cycle and W looks duty cycle, first synthesis unit includes:
a first synthesizing subunit, configured to synthesize the U-phase duty ratio as an effective U-phase duty ratio if the U-phase duty ratio is not equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold;
a second synthesizing subunit, configured to synthesize the V-phase duty ratio into an effective V-phase duty ratio if the V-phase duty ratio is not equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold;
a third synthesizing subunit, configured to synthesize the W-phase duty cycle into an effective W-phase duty cycle if the W-phase duty cycle is not equal to the preset maximum duty cycle threshold or the preset minimum duty cycle threshold.
Optionally, the preset three-phase balance compensation value includes: presetting a U-phase balance compensation value, a V-phase balance compensation value and a W-phase balance compensation value.
Optionally, the second synthesis unit comprises:
a fourth synthesizing subunit, configured to, if the three-phase duty ratio is equal to the preset maximum duty ratio threshold, superimpose a U-phase duty ratio in the three-phase duty ratio on the preset U-phase balance compensation value to obtain a first U-phase duty ratio, and synthesize the first U-phase duty ratio as an effective U-phase duty ratio;
a fifth synthesizing subunit, configured to, if the three-phase duty ratio is equal to the preset maximum duty ratio threshold, superimpose a V-phase duty ratio in the three-phase duty ratio on the preset V-phase balance compensation value to obtain a first V-phase duty ratio, and synthesize the first V-phase duty ratio as an effective V-phase duty ratio;
and the sixth synthesis subunit is configured to, if the three-phase duty ratio is equal to the preset maximum duty ratio threshold, superimpose the W-phase duty ratio in the three-phase duty ratio on the preset W-phase balance compensation value to obtain a first W-phase duty ratio, and synthesize the first W-phase duty ratio as an effective W-phase duty ratio.
Optionally, the second synthesis unit further comprises:
a seventh synthesizing subunit, configured to, if the three-phase duty ratio is equal to the preset minimum duty ratio threshold, subtract the preset U-phase balance compensation value from a U-phase duty ratio in the three-phase duty ratio to obtain a second U-phase duty ratio, and synthesize the second U-phase duty ratio as an effective U-phase duty ratio;
the eighth synthesizing subunit is configured to, if the three-phase duty ratio is equal to the preset minimum duty ratio threshold, subtract the preset V-phase balance compensation value from the V-phase duty ratio in the three-phase duty ratio to obtain a second V-phase duty ratio, and synthesize the second V-phase duty ratio as an effective V-phase duty ratio;
and the ninth synthesis subunit is configured to, if the three-phase duty ratio is equal to the preset minimum duty ratio threshold, subtract the preset W-phase balance compensation value from the W-phase duty ratio in the three-phase duty ratio to obtain a second W-phase duty ratio, and synthesize the second W-phase duty ratio as an effective W-phase duty ratio.
The specific implementation of the control system for bus balance of the three-level converter of the present invention is substantially the same as the embodiments of the control method for bus balance of the three-level converter, and is not described herein again.
In addition, the present invention also provides a terminal device, which includes: a memory, a processor, a communication bus, and a control program for bus balancing of a three-level converter stored on the memory,
the communication bus is used for realizing communication connection between the processor and the memory;
the processor is used for executing the control program of the bus balance of the Internet-based three-level converter to realize the following steps:
acquiring a three-phase duty ratio of the three-level converter;
respectively synthesizing the three-phase duty ratios into effective three-phase duty ratios according to preset duty ratio thresholds;
and generating symmetrical PWM driving pulse signals according to the effective three-phase duty ratio so as to control bus balance.
The specific implementation of the computer device of the present invention is the same as the above-mentioned embodiments of the method for controlling bus balance of the three-level converter, and is not described herein again.
Furthermore, the present invention also provides a computer storage medium storing one or more programs, the one or more programs further executable by one or more processors for:
acquiring a three-phase duty ratio of the three-level converter;
respectively synthesizing the three-phase duty ratios into effective three-phase duty ratios according to preset duty ratio thresholds;
and generating symmetrical PWM driving pulse signals according to the effective three-phase duty ratio so as to control bus balance.
The specific implementation of the computer storage medium of the present invention is substantially the same as the above-mentioned embodiments of the method for controlling bus balance of a three-level converter, and is not described herein again.
Furthermore, the present invention also provides a computer program product having one or more programs stored thereon, the one or more programs being further executable by one or more processors for:
acquiring a three-phase duty ratio of the three-level converter;
respectively synthesizing the three-phase duty ratios into effective three-phase duty ratios according to preset duty ratio thresholds;
and generating symmetrical PWM driving pulse signals according to the effective three-phase duty ratio so as to control bus balance.
The specific implementation of the computer program product of the present invention is substantially the same as the above-mentioned embodiments of the method for controlling the bus balance of the three-level converter, and is not described herein again.
Further, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.
The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.
Through the description of the foregoing embodiments, it is clear to those skilled in the art that the method of the foregoing embodiments may be implemented by software plus a necessary general hardware platform, and certainly may also be implemented by hardware, but in many cases, the former is a better implementation. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which is stored in a storage medium (such as ROM/RAM, magnetic disk, optical disk) and includes instructions for enabling a terminal device (such as a mobile phone, a computer, a server, an air conditioner, or a network device) to execute the method according to the embodiments of the present invention.
The above description is only an alternative embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (8)
1. A control method for bus balance of a three-level converter is characterized by being applied to a space vector generator and comprising the following steps:
acquiring a three-phase duty ratio of the three-level converter;
detecting whether the three-phase duty ratio is equal to a preset maximum duty ratio threshold value or a preset minimum duty ratio threshold value, wherein the preset maximum duty ratio threshold value is a maximum limit value of a required three-phase duty ratio when the three-level converter performs bus balance control in the grid voltage, and the preset minimum duty ratio threshold value is a minimum limit value of the required three-phase duty ratio when the three-level converter performs bus balance control in the grid voltage;
if not, respectively synthesizing the three-phase duty ratios into effective three-phase duty ratios;
if so, synthesizing the three-phase duty ratio into an effective three-phase duty ratio based on a preset three-phase balance compensation value;
and generating symmetrical PWM driving pulse signals according to the effective three-phase duty ratio to control the bus balance.
2. The method of controlling bus balancing for a three-level converter of claim 1, wherein the three-phase duty cycle comprises: if not, respectively synthesizing the three-phase duty ratio into an effective three-phase duty ratio, and the method comprises the following steps of:
if the U-phase duty ratio is not equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold, synthesizing the U-phase duty ratio as an effective U-phase duty ratio;
if the V-phase duty ratio is not equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold, synthesizing the V-phase duty ratio as an effective V-phase duty ratio;
and if the W-phase duty ratio is not equal to the preset maximum duty ratio threshold or the preset minimum duty ratio threshold, synthesizing the W-phase duty ratio into an effective W-phase duty ratio.
3. The method of claim 2, wherein the predetermined three-phase balance compensation value comprises: presetting a U-phase balance compensation value, a V-phase balance compensation value and a W-phase balance compensation value.
4. The method for controlling bus balancing of a three-level converter according to claim 3, wherein if yes, the step of synthesizing the three-phase duty ratio into an effective three-phase duty ratio based on a preset three-phase balance compensation value comprises:
if the three-phase duty ratio is equal to the preset maximum duty ratio threshold value, overlapping the U-phase duty ratio in the three-phase duty ratio with the preset U-phase balance compensation value to obtain a first U-phase duty ratio, and synthesizing the first U-phase duty ratio into an effective U-phase duty ratio;
if the three-phase duty ratio is equal to the preset maximum duty ratio threshold value, superposing a V-phase duty ratio in the three-phase duty ratio with the preset V-phase balance compensation value to obtain a first V-phase duty ratio, and synthesizing the first V-phase duty ratio into an effective V-phase duty ratio;
and if the three-phase duty ratio is equal to the preset maximum duty ratio threshold value, overlapping the W-phase duty ratio in the three-phase duty ratio with the preset W-phase balance compensation value to obtain a first W-phase duty ratio, and synthesizing the first W-phase duty ratio into an effective W-phase duty ratio.
5. The method for controlling bus balancing of a three-level converter according to claim 3, wherein if yes, the step of synthesizing the three-phase duty ratio as an effective three-phase duty ratio based on a preset three-phase balance compensation value further comprises:
if the three-phase duty ratio is equal to the preset minimum duty ratio threshold value, subtracting the preset U-phase balance compensation value from the U-phase duty ratio in the three-phase duty ratio to obtain a second U-phase duty ratio, and synthesizing the second U-phase duty ratio into an effective U-phase duty ratio;
if the three-phase duty ratio is equal to the preset minimum duty ratio threshold value, subtracting the preset V-phase balance compensation value from the V-phase duty ratio in the three-phase duty ratio to obtain a second V-phase duty ratio, and synthesizing the second V-phase duty ratio as an effective V-phase duty ratio;
and if the three-phase duty ratio is equal to the preset minimum duty ratio threshold value, subtracting the preset W-phase balance compensation value from the W-phase duty ratio in the three-phase duty ratio to obtain a second W-phase duty ratio, and synthesizing the second W-phase duty ratio into an effective W-phase duty ratio.
6. A control device for bus balance of a three-level converter is characterized in that the control device for bus balance of the three-level converter is applied to a space vector generator, and comprises:
the acquisition module is used for acquiring the three-phase duty ratio of the three-level converter;
the detection module is used for detecting whether the three-phase duty ratio is equal to a preset maximum duty ratio threshold value or a preset minimum duty ratio threshold value, wherein the preset maximum duty ratio threshold value is a maximum limit value of a required three-phase duty ratio when the three-level converter performs bus balance control in the power grid voltage, and the preset minimum duty ratio threshold value is a minimum limit value of the required three-phase duty ratio when the three-level converter performs bus balance control in the power grid voltage;
the first synthesis module is used for respectively synthesizing the three-phase duty ratios into effective three-phase duty ratios if the three-phase duty ratios are not the same;
the second synthesis module is used for synthesizing the three-phase duty ratio into an effective three-phase duty ratio based on a preset three-phase balance compensation value if the three-phase balance compensation value is positive;
and the control module is used for generating symmetrical PWM driving pulse signals according to the effective three-phase duty ratio so as to control the bus balance.
7. A terminal device, characterized in that the terminal device comprises: a memory, a processor, a communication bus, and a control program for bus balancing of a three-level converter stored on the memory,
the communication bus is used for realizing communication connection between the processor and the memory;
the processor is used for executing an Internet-based control program of the three-level converter bus balance to realize the steps of the control method of the three-level converter bus balance according to any one of claims 1 to 5.
8. A computer storage medium, characterized in that the computer storage medium has stored thereon a control program of a three-level converter bus bar balance, which when executed by a processor implements the steps of the control method of a three-level converter bus bar balance according to any one of claims 1 to 5.
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