CN113162084B

CN113162084B - Control method and device of power converter and storage medium

Info

Publication number: CN113162084B
Application number: CN202110282953.1A
Authority: CN
Inventors: 高锦凤; 但志敏; 侯贻真
Original assignee: Jiangsu Contemporary Amperex Technology Ltd
Current assignee: Jiangsu Contemporary Amperex Technology Ltd
Priority date: 2020-12-09
Filing date: 2020-12-09
Publication date: 2023-11-14
Anticipated expiration: 2040-12-09
Also published as: CN113162084A; CN112234640B; CN112234640A

Abstract

The application provides a control method, a device and a storage medium of a power converter, wherein the theoretical output voltage of a first converter is obtained according to the voltage of a power grid; acquiring theoretical input voltage of the second converter according to the voltage of the battery, wherein the power grid transmits electric energy to the battery through the first converter and the second converter in sequence; and setting the actual output voltage of the first converter in a first power supply period according to the theoretical output voltage of the first converter and the theoretical input voltage of the second converter, wherein the first power supply period is the current period of the power grid for transmitting electric energy to the battery.

Description

Control method and device of power converter and storage medium

The application is based on application number 202011433037.5, application date 2020, 12 months 09, and application name "control method, device and storage medium of power converter" of Jiangsu New energy science and technology Co., ltd.

Technical Field

The present application relates to the field of power technologies, and in particular, to a method and an apparatus for controlling a power converter, and a storage medium.

Background

Renewable energy sources (e.g., solar energy, wind energy, etc.) are being heavily switched into electrical power systems. Since the discontinuity of the renewable energy source causes fluctuation of power generation, other energy sources (such as a battery energy storage system) are required to compensate for smoothing the variability of the renewable energy source, thereby ensuring the stability of the grid frequency and suppressing the voltage rise caused by the reverse power flow.

The externally pluggable hybrid electric vehicle and the pure electric vehicle become an integral part of the power distribution system. Because the batteries with larger capacity are arranged on the automobiles, the electric automobile in a stopped state is connected into a power grid, the electric automobile can be used as a movable distributed energy storage device, and the residual electric energy is controllably fed back to the power grid on the premise of meeting the running requirements of users of the electric automobile. The Vehicle-to-Grid (V2G) technology and the Grid-to-Vehicle (G2V) technology realize bidirectional interaction between the Grid and the Vehicle, and are important components of the smart Grid technology.

When the load of the power grid is too high, the power grid is fed by the battery of the electric automobile through the power converter. When the load of the power grid is too low, the power grid charges the battery of the electric automobile through the power converter. How to improve the energy transmission efficiency of V2G is one of the problems to be solved.

Disclosure of Invention

The application provides a control method and device of a power converter and a storage medium, which can improve energy transmission efficiency between a battery and a power grid of a vehicle.

In a first aspect, an embodiment of the present application provides a method for controlling a power converter, including: obtaining theoretical output voltage of the first converter according to voltage of a source end, wherein the source end is one of a battery and a power grid; acquiring theoretical input voltage of a second converter according to voltage of a destination end, wherein the destination end is the other of a battery and a power grid, and the source end sequentially transmits electric energy to the destination end through the first converter and the second converter; according to the theoretical output voltage of the first converter and the theoretical input voltage of the second converter, setting the actual output voltage of the first converter in a first power supply period, wherein the first power supply period is the current period of transmitting electric energy from a source end to a destination end.

In one implementation, the source terminal is a battery, the destination terminal is a power grid, and setting the actual output voltage of the first converter in the first power supply period according to the theoretical output voltage of the first converter and the theoretical input voltage of the second converter includes: if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than the minimum operating voltage of the second converter and smaller than the maximum bearing voltage of the first converter and the second converter, the larger value is set as the actual output voltage of the first converter in the first power supply period.

In one implementation, setting the actual output voltage of the first converter for the first power supply period based on the theoretical output voltage of the first converter and the theoretical input voltage of the second converter includes: and if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than the minimum working voltage of the second converter and smaller than the maximum bearing voltage of the first converter and the second converter, and the absolute value of the difference value between the larger value and the actual output voltage of the first converter in the second power supply period is smaller than or equal to a first voltage threshold value, setting the larger value as the actual output voltage of the first converter in the first power supply period, wherein the second power supply period is the previous period of the first power supply period.

In one implementation, setting the actual output voltage of the first converter for the first power supply period based on the theoretical output voltage of the first converter and the theoretical input voltage of the second converter includes: if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than the minimum working voltage of the second converter and smaller than the maximum bearing voltage of the first converter and the second converter, and the absolute value of the difference value between the larger value and the actual output voltage of the first converter in the second power supply period is larger than the first voltage threshold value, the actual output voltage of the first converter in the first power supply period is set according to the actual output voltage of the first converter in the second power supply period and the first voltage threshold value, wherein the second power supply period is the period before the first power supply period.

In one implementation, setting the actual output voltage of the first converter for the first power supply period based on the theoretical output voltage of the first converter and the theoretical input voltage of the second converter includes: and if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is smaller than or equal to the minimum working voltage of the second converter, setting the minimum working voltage of the second converter as the actual output voltage of the first converter in the first power supply period.

In one implementation, setting the actual output voltage of the first converter for the first power supply period based on the theoretical output voltage of the first converter and the theoretical input voltage of the second converter includes: and if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than or equal to the maximum bearing voltage of the first converter and the second converter, setting the maximum bearing voltage of the first converter and the second converter as the actual output voltage of the first converter in the first power supply period.

In one implementation, the source terminal is a power grid, the destination terminal is a battery, and setting the actual output voltage of the first converter in the first power supply period according to the theoretical output voltage of the first converter and the theoretical input voltage of the second converter includes: if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than the minimum operating voltage of the first converter and smaller than the maximum bearing voltage of the first converter and the second converter, the larger value is set as the actual output voltage of the first converter in the first power supply period.

In one implementation, setting the actual output voltage of the first converter for the first power supply period based on the theoretical output voltage of the first converter and the theoretical input voltage of the second converter includes: and if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than the minimum working voltage of the first converter and smaller than the maximum bearing voltage of the first converter and the second converter, and the absolute value of the difference value between the larger value and the actual output voltage of the first converter in the second power supply period is smaller than or equal to a second voltage threshold value, setting the larger value as the actual output voltage of the first converter in the first power supply period, wherein the second power supply period is the previous period of the first power supply period.

In one implementation, setting the actual output voltage of the first converter for the first power supply period based on the theoretical output voltage of the first converter and the theoretical input voltage of the second converter includes: and if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than the minimum working voltage of the first converter and smaller than the maximum bearing voltage of the first converter and the second converter, and the absolute value of the difference value between the larger value and the actual output voltage of the first converter in the second power supply period is larger than a first voltage threshold value, setting the actual output voltage of the first converter in the first power supply period according to the actual output voltage of the first converter in the second power supply period and the first voltage threshold value, wherein the second power supply period is the period before the first power supply period.

In one implementation, setting the actual output voltage of the first converter for the first power supply period based on the theoretical output voltage of the first converter and the theoretical input voltage of the second converter includes: and if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is smaller than or equal to the minimum working voltage of the first converter, setting the minimum working voltage of the first converter as the actual output voltage of the first converter in the first power supply period.

In a second aspect, an embodiment of the present application provides a control apparatus for a power converter, including: an acquisition unit for acquiring a theoretical output voltage of the first converter according to a voltage of the source terminal, and acquiring a theoretical input voltage of the second converter according to a voltage of the destination terminal, the source end is one of a battery and a power grid, the destination end is the other of the battery and the power grid, and the source end transmits electric energy to the destination end through the first converter and the second converter in sequence; the processing unit is used for setting the actual output voltage of the first converter in a first power supply period according to the theoretical output voltage of the first converter and the theoretical input voltage of the second converter, wherein the first power supply period is the current period of transmitting electric energy from the source end to the destination end.

In a third aspect, an embodiment of the present application provides a computer readable storage medium, where a program or an instruction is stored, where the program or the instruction, when executed by a processor, implement a method for controlling a power converter in the technical solution of the first aspect.

Based on the theoretical output voltage of the first converter and the theoretical output voltage of the second converter, the actual output voltage of the first converter in the current period is adjusted in real time, and the energy transmission efficiency between the source end and the destination end is improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute a limitation on the application.

FIG. 1 is a schematic diagram of a system architecture of a bi-directional V2G;

FIG. 2 is a schematic diagram of a hardware configuration of a power converter;

fig. 3 is a schematic flow chart of a control method of a power converter according to an embodiment of the present application;

fig. 4 is a flowchart of a control method of a power converter according to an embodiment of the present application;

FIG. 5 is a flowchart illustrating another control method of a power converter according to an embodiment of the present application;

fig. 6 is a flowchart illustrating a control method of a power converter according to an embodiment of the present application;

FIG. 7 is a flowchart illustrating another control method of a power converter according to an embodiment of the present application;

fig. 8 is a schematic diagram of a control device of a power converter according to an embodiment of the present application;

fig. 9 is a schematic diagram of a control device of a power converter according to an embodiment of the present application.

Detailed Description

Features and exemplary embodiments of various aspects of the application are described in detail below. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the application. It will be apparent, however, to one skilled in the art that the present application may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the application by showing examples of the application. The present application is in no way limited to any specific configuration and algorithm set forth below. In the drawings and the following description, well-known structures and techniques have not been shown in order to avoid unnecessarily obscuring the present application.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, 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 … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises an element.

For convenience of description, the V2G technology and the G2V technology are collectively referred to as a bidirectional V2G technology.

Fig. 1 is a schematic diagram of a system architecture of a bidirectional V2G. As shown in fig. 1, a source terminal 10 transmits electric power to a destination terminal 13 through a first inverter 11 and a second inverter 12.

The first converter 11 and the second converter 12 constitute a power converter between the source 10 and the destination 13.

The power converter can be a bidirectional power converter, so that energy transmission from a battery of the electric automobile to a power grid can be realized, and energy transmission from the power grid to the battery of the electric automobile can be realized.

When the source terminal 10 is a battery of an electric vehicle and the destination terminal 13 is a power grid, the battery of the electric vehicle transmits electric energy to the power grid through the first converter 11 and the second converter 12 in sequence. The first converter 11 is a dc/dc converter, and the second converter 12 is a dc/ac converter.

When the source end 10 is a power grid and the destination end is a battery of an electric automobile, the power grid transmits electric energy to the battery of the electric automobile through the first converter 11 and the second converter 12 in sequence. The first converter 11 is an ac/dc converter, and the second converter 12 is a dc/dc converter.

The battery in the embodiment of the application may be a battery cell, a battery module, a battery pack, or the like in a vehicle, which is not limited herein.

Fig. 2 is a schematic diagram of a hardware configuration of the power converter. The dc/ac converter is a totem pole dc/ac converter, and the dc/dc converter is an isolated resonant dc/dc converter. The dc/ac converter and the dc/dc converter in the embodiment of the present invention are not limited to the specific configuration shown in fig. 2.

As shown in fig. 2, the totem pole dc/ac converter 23 includes a power switching device G1, a power switching device G2, a power switching device G3, a power switching device G4, an ac side filter inductance Ls, a bus capacitor Cdc, and the like. The bidirectional resonant dc/dc converter 24 includes a power switching device G5, a power switching device G6, a power switching device G7, a power switching device G8, a power switching device G9, a power switching device G10, a power switching device G11, a power switching device G12, an inductance Lrp, an inductance Lrs, a capacitance Crp, a capacitance Crs, a capacitance Co, a transformer Tr, and the like.

Because the voltage of the power grid and the battery of the electric automobile fluctuate within a certain range, in the prior art, the actual output voltage of the first converter in the first power supply period is fixedly arranged, and the energy transmission efficiency between the vehicle and the power grid is reduced.

Fig. 3 is a flowchart illustrating a control method of a power converter according to an embodiment of the present application. As shown in fig. 3, the control method of the power converter includes the following steps. The control method of the power converter may be performed by a controller, which may be present alone or may be integrated in a battery management system (Battery Management System, BMS) of the vehicle.

S301, obtaining theoretical output voltage of the first converter according to voltage of a source end, wherein the source end is one of a battery and a power grid, and the destination end is the other of the battery and the power grid.

If the source terminal is a power grid, the destination terminal is a battery. Or if the source terminal is a battery, the destination terminal is a power grid. The source end transmits electric energy to the destination end through the first converter and the second converter in sequence.

S302, obtaining the theoretical input voltage of the second converter according to the voltage of the destination terminal.

S303, setting the actual output voltage of the first converter in a first power supply period according to the theoretical output voltage of the first converter and the theoretical input voltage of the second converter, wherein the first power supply period is the current period of transmitting electric energy from a source end to a destination end.

The actual output voltage of the first converter in the first power supply period is the actual input voltage of the second converter in the first power supply period. Based on the actual output voltage of the first converter, the source terminal and the destination terminal perform electric energy transmission in the first power supply period through the first converter and the second converter.

The voltage of the source terminal and the voltage of the destination terminal can be detected and obtained in real time.

If the source terminal is a battery and the destination terminal is a power grid, the first converter may be a dc/dc converter and the second converter may be a dc/ac converter. Obtaining a theoretical output voltage of the DC/DC converter according to the voltage of the battery; acquiring theoretical input voltage of the direct current/alternating current converter according to the voltage of the power grid; the actual output voltage of the DC/DC converter in the first power supply period is set based on the theoretical output voltage of the DC/DC converter and the theoretical input voltage of the DC/AC converter.

If the source terminal is a power grid and the destination terminal is a battery, the first converter may be a dc/ac converter and the second converter may be a dc/dc converter. Obtaining a theoretical output voltage of the direct current/alternating current converter according to the voltage of the power grid; acquiring theoretical input voltage of the direct current/direct current converter according to the voltage of the battery; the actual output voltage of the DC/AC converter in the first power supply period is set based on the theoretical output voltage of the DC/AC converter and the theoretical input voltage of the DC/DC converter.

The source end transmits electric energy to the destination end through two stages of converters, and in the electric energy transmission process, the voltage of the source end and/or the voltage of the destination end change within a certain range, and each stage of converter has the influence of energy conversion efficiency factors. The theoretical output voltage of the first converter is obtained according to the voltage of the source end, the theoretical input voltage of the second converter is obtained according to the voltage of the destination end, the actual output voltage of the first converter in the first power supply period is set according to the theoretical output voltage of the first converter and the theoretical input voltage of the second converter, and the efficiency of the source end for transmitting electric energy to the destination end through the two-stage converter is improved. Fig. 4 is a flowchart illustrating a control method of a power converter according to a second embodiment of the present application. This embodiment is described in detail by taking V2G as an example. As shown in fig. 4, the control method of the power converter may include the following steps.

S401, obtaining the theoretical output voltage of the first converter according to the voltage of the battery.

The first converter may in particular be a dc/dc converter which may control the magnitude of the output voltage by varying the turn ratio of the transformer in the converter. The theoretical output voltage of the first converter may be the product of the voltage of the battery and the turn ratio of the first converter.

The calculation of the theoretical output voltage of the first converter can be obtained according to the following equation (1):

Vb＝Vbat×n (1)

where Vb is the theoretical output voltage of the first converter, vbat is the voltage of the battery, and n is the turn ratio of the first converter. If the turn ratio of the first transformer is 15:13, then

Alternatively, a functional model of the voltage of the battery, the turn ratio of the first inverter, and the theoretical output voltage of the first inverter is provided according to the specific structure of the first inverter, and is not limited herein. For an isolated resonant dc/dc converter, the turn ratio of the converter represents the transformation ratio of the transformer of the isolated resonant dc/dc converter. The closer the ratio of the output voltage of the converter to the voltage of the battery is to the transformation ratio of the transformer of the isolated resonant dc/dc converter, the higher the energy transfer efficiency of the isolated resonant dc/dc converter. I.e. the closer the output voltage of the first converter is to the theoretical output voltage of the first converter, the higher the energy transfer efficiency of the first converter.

The theoretical output voltage of the first converter is obtained according to the voltage of the battery, specifically, the theoretical output voltage of the first converter is obtained according to the voltage of the battery and the turn ratio of the first converter.

S402, acquiring the theoretical input voltage of the second converter according to the voltage of the power grid.

The second converter may be embodied as a dc/ac converter, and the theoretical input voltage of the second converter may be obtained according to the voltage of the power grid and the maximum modulation ratio of the second converter. The maximum modulation ratio is the ratio of the modulation peak value and the carrier wave peak value in the PWM technology, and the modulation peak value may be the ratio of the grid voltage peak value to the input voltage of the second converter. The maximum modulation ratio of the second converter may specifically be the maximum modulation ratio of the dc/ac converter.

Alternatively, a functional model of the voltage of the power grid, the maximum modulation ratio of the second converter, and the theoretical input voltage of the second converter may be set according to the specific structure of the second converter, which is not limited herein. For example, the theoretical input voltage of the second converter may be the product of the first sum and the first quotient. The first sum is the sum of the voltage of the grid and the voltage error margin. The first quotient is the quotient of the efficiency conversion parameter and the maximum modulation ratio. The calculation of the theoretical input voltage of the second converter can be obtained according to the following equation (2):

Va＝Vbat×m (2)

In this example, m in expression (2) is the maximum modulation ratio of the second converter, and correspondingly Va is the theoretical input voltage of the second converter.

If the second converter is specifically a totem pole dc/ac converter, the maximum modulation ratio of the second converter may be the maximum modulation ratio of the topology of the totem pole dc/ac converter. The voltage error margin VLs may be specifically a product of an ac side filter inductance of the totem pole dc/ac converter, a power frequency angular frequency of the totem pole dc/ac converter, and an ac side maximum current of the totem pole dc/ac converter. The input voltage of the second converter needs to be greater than the s-times alternating-current side voltage, and the closer the input voltage of the second converter is to the s-times alternating-current side voltage, the higher the energy transmission efficiency of the totem pole type direct current/alternating current converter. I.e. the closer the voltage of the second converter is to the theoretical input voltage of the second converter, the higher the energy transfer efficiency of the second converter.

S403, setting the actual output voltage of the first converter in the first power supply period according to the theoretical output voltage of the first converter and the theoretical input voltage of the second converter.

Alternatively, if the larger value of the theoretical output voltage of the first inverter and the theoretical input voltage of the second inverter is greater than the minimum operating voltage of the second inverter and less than the maximum withstand voltage of the first inverter and the second inverter, the larger value is set as the actual output voltage of the first inverter in the first power supply period. In particular, the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter may be set as the voltage of the dc bus between the first converter and the second converter.

The minimum working voltage of the second converter is the minimum voltage supported by the normal working of the second converter. The maximum withstand voltage of the first converter and the second converter is the maximum voltage that the first converter and the second converter support for normal operation.

By selecting a larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter, the first converter and the second converter can work normally, and high energy transmission efficiency is achieved.

Optionally, if the larger value of the theoretical output voltage of the first inverter and the theoretical input voltage of the second inverter is smaller than or equal to the minimum operating voltage of the second inverter, the minimum operating voltage of the second inverter is set to the actual output voltage of the first inverter in the first power supply period.

And under the condition that the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is smaller than or equal to the minimum working voltage of the second converter, the energy transmission efficiency is improved as much as possible on the basis of ensuring safe and stable energy transmission between the battery and the power grid, so that the minimum working voltage of the second converter is set to be the actual output voltage of the converter in the first power supply period.

Optionally, if the larger value of the theoretical output voltage of the first inverter and the theoretical input voltage of the second inverter is greater than or equal to the maximum withstand voltage of the first inverter and the second inverter, the maximum withstand voltage of the first inverter and the second inverter is set to the actual output voltage of the first inverter in the first power supply period.

And under the condition that the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than or equal to the maximum bearing voltage of the first converter and the second converter, the energy transmission efficiency is improved as much as possible on the basis of ensuring safe and stable energy transmission between the battery and the power grid, so that the maximum bearing voltage of the first converter and the second converter is set as the actual output voltage of the first converter in the first power supply period.

In the process of setting the actual output voltage of the first converter in the first power supply period, if the actual output voltage of the first converter in the first power supply period is too far away from the actual output voltage of the first converter in the last power supply period, adverse effects can be caused on energy transmission between the battery and the power grid, for example, the problem that the output voltage of the first converter is overshot in the adjusting process, and the output voltage of the first converter exceeds the withstand voltage value of an energy transmission circuit between the battery and the power grid.

Further, the actual output voltage of the first inverter in the second power supply period needs to be considered when setting the actual output voltage of the first inverter in the first power supply period. The second power supply period is the previous period of the first power supply period.

And if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than the minimum working voltage of the second converter and smaller than the maximum bearing voltage of the first converter and the second converter, and the absolute value of the difference value between the larger value and the actual output voltage of the first converter in the second power supply period is smaller than or equal to a first voltage threshold value, setting the larger value as the actual output voltage of the first converter in the first power supply period.

The first voltage threshold is a threshold for judging whether a voltage change greatly occurs. The larger value of the theoretical output voltage of the first inverter and the theoretical input voltage of the second inverter, and the difference from the actual output voltage of the first inverter in the second power supply period, represent the amount of change in the output voltage of the first inverter between the first power supply period and the second power supply period.

The absolute value of the difference between the theoretical output voltage of the first converter and the theoretical input voltage of the second converter and the actual output voltage of the first converter in the second power supply period is smaller than or equal to the first voltage threshold value, which indicates that the difference between the actual output voltage of the first converter in the first power supply period and the actual output voltage of the first converter in the second power supply period, which is set according to the larger value, is within an acceptable range, and the larger value can be directly set as the actual output voltage of the first converter in the first power supply period, so that the energy transmission safety between the battery and the power grid is ensured.

And if the absolute value of the difference between the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter and the actual output voltage of the first converter in the second power supply period is larger than a first voltage threshold value, setting the actual output voltage of the first converter in the first power supply period according to the actual output voltage of the first converter in the second power supply period and the first voltage threshold value. That is, when the larger value is larger than the actual output voltage of the first converter in the second power supply period, the first voltage threshold value is added to the actual output voltage of the first converter in the second power supply period as the actual output voltage of the first converter in the first power supply period, and when the larger value is smaller than the actual output voltage of the first converter in the second power supply period, the first voltage threshold value is subtracted from the actual output voltage of the first converter in the second power supply period as the actual output voltage of the first converter in the first power supply period.

V2G is described below with a specific example. Fig. 5 is a flowchart illustrating a control method of another power converter according to the second embodiment of the present application. In this example, the preset initial voltage is 380V; the minimum operating voltage of the second converter is 325V; the maximum withstand voltage of the first converter and the second converter is 430V.

As shown in fig. 5, the control method of the power converter may include the following steps.

In S501, a theoretical output voltage V1 of the first inverter and a theoretical input voltage V2 of the second inverter are calculated.

In S502, the larger value of the theoretical output voltage V1 of the first inverter and the theoretical input voltage V2 of the second inverter is taken as V3. I.e. v3=max (V1, V2), max representing the maximum value.

In S503, it is determined whether V3 is greater than the maximum withstand voltage 430V of the first inverter and the second inverter, and if V3 is less than 430V, the process goes to S604; if V3 > 430V, V3 is set to 430V, and the process goes to S505.

In S504, it is determined whether V3 is smaller than the minimum operating voltage 325V of the first converter, and if V3 > 325V, the process goes to S505; if V3 < 325V, V3 is set to 325V, and the process goes to S505.

In S505, it is determined whether the absolute value of the difference between the actual output voltages Vrefold and V3 of the first converter in the second power supply period is less than or equal to the first voltage threshold value Vstep1, if Vrefold-v3|is not more than Vstep1, the process goes to S506; if |Vrefold-V3| > Vstep1, go to S507.

In S506, vref=v3 is taken, and the process goes to S510.

In S507, it is determined whether the actual output voltage vrefald of the first converter in the second power supply period is greater than V3, and if vrefald > V3, the process jumps to S508; if Vrefold is less than or equal to V3, the process goes to S509.

In S508, vref=vrefold-Vstep 1 is taken, and the process goes to S510.

In S509, vref=vrefald+vstep1 is taken, and the process goes to S510.

In S510, the actual output voltage of the first inverter in the first power supply period is set to Vref, and the process goes to S511.

In step S511, the value of the actual output voltage vrefald of the first converter in the second power supply period is updated to Vref. And Vrefold used in the next cycle process is Vref obtained in the current cycle.

The first shows the energy transfer efficiency under the same ac and dc voltage conditions using the scheme of the embodiment of the present application and using the fixed voltage scheme. The ac voltage is the source terminal voltage and the dc voltage is the destination terminal voltage. Alternatively, the ac voltage is a destination terminal voltage and the dc voltage is a source terminal voltage. The fixed voltage was set to 400V.

List one

DC voltage	Ac voltage	Fixed voltage scheme	Scheme of the embodiment of the application
				240	187	0.8658	0.900936
500	187	0.884078	0.90535
				240	220	0.8757	0.890958
500	220	0.894187	0.9082
				240	253	0.8577	0.8784
350	253	0.913927	0.935984
				500	253	0.875807	0.91485

In the first table, the units of the direct current voltage and the alternating current voltage are volts, namely V, the fixed voltage scheme is the energy transmission efficiency obtained by adopting the fixed voltage method, and the scheme of the embodiment of the application is the energy transmission efficiency obtained by adopting the scheme of the embodiment of the application.

Fig. 6 is a flowchart of a control method of a power converter according to a third embodiment of the present application. As shown in fig. 6, the control method of the power converter may include S601 to S603.

S601, obtaining the theoretical output voltage of the first converter according to the voltage of the power grid.

The first converter may be a dc/ac converter, and the specific content of the dc/ac converter may be referred to in the description of the second S402 section of the embodiment of the present application, which is not repeated.

S602, obtaining the theoretical input voltage of the second converter according to the voltage of the battery.

The second converter may be a dc/dc converter, and the specific content of the dc/dc converter may be referred to in the description related to the second S401 of the embodiment of the present application, which is not repeated.

S603, setting the actual output voltage of the first converter in the first power supply period according to the theoretical output voltage of the first converter and the theoretical input voltage of the second converter.

It should be noted that S603 may be configured to compare the theoretical output voltage of the first inverter with the theoretical input voltage of the second inverter, and compare one of the theoretical output voltage of the first inverter and the theoretical input voltage of the second inverter with the minimum operating voltage of the first inverter and the maximum bearing voltage of the first inverter, and compare the actual output voltage of the first inverter in the second power supply period, the theoretical output voltage of the first inverter, the theoretical input voltage of the second inverter, the minimum operating voltage of the first inverter and the maximum bearing voltage of the first inverter with each other, respectively, to obtain the actual output voltage of the first inverter in the first power supply period.

Optionally, if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is greater than the minimum operating voltage of the first converter and less than the maximum withstand voltage of the first converter and the second converter, the larger value is set to the actual output voltage of the first converter in the first power supply period.

The minimum working voltage of the first converter is the minimum voltage supported by the normal working of the first converter. The maximum withstand voltage of the first converter and the second converter is the maximum voltage that the first converter and the second converter support for normal operation.

The larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is selected, so that the first converter and the second converter can work normally, and the higher energy transmission efficiency of the whole system can be realized.

Fig. 7 is a flowchart illustrating an example of a control method of a power converter according to a third embodiment of the present application. As shown in fig. 7, the control method of the power converter may include S701 to S711.

In S701, a theoretical output voltage V1 of the first inverter and a theoretical input voltage V2 of the second inverter are calculated.

In S702, the larger value of the theoretical output voltage V1 of the first inverter and the theoretical input voltage V2 of the second inverter is taken as V3. I.e. v3=max (V1, V2), max representing the maximum value.

In S703, it is determined whether V3 is greater than the maximum withstand voltage 430V of the first inverter and the second inverter, and if V3 is less than 430V, the process goes to S704; if V3 > 430V, V3 is set to 430V, and the process goes to S705.

In S704, it is determined whether V3 is smaller than the minimum operating voltage 325V of the first converter, and if V3 is greater than 325V, the process goes to S705; if V3 < 325V, V3 is set to 325V, and the process goes to S705.

In S705, it is determined whether the absolute value of the difference between the actual output voltages Vrefold and V3 of the first converter in the second power supply period is less than or equal to the second voltage threshold value Vstep2, if Vrefold-v3|is not more than Vstep2, the process goes to S706; if |Vrefold-V3| > Vstep2, go to S707.

In S706, vref=v3 is taken, and the process goes to S710.

In S707, it is determined whether the actual output voltage vrefald of the first converter in the second power supply period is greater than V3, and if vrefald > V3, the process goes to S708; if Vrefold is less than or equal to V3, the process proceeds to S709.

In S708, vref=vrefold-Vstep 2 is taken, and the process goes to S710.

In S709, vref=vrefald+vstep2 is taken, and the process goes to S710.

In S710, the actual output voltage of the first inverter in the first power supply period is set to Vref, and the process goes to S701.

In step S711, the value of the actual output voltage vrefald of the first converter in the second power supply period is updated to Vref. And Vrefold used in the next cycle process is Vref obtained in the current cycle.

Fig. 8 is a schematic structural diagram of a control device of a power converter according to an embodiment of the present application. As shown in fig. 8, the control device 800 of the power converter may include an acquisition unit 801 and a processing unit 802 for performing the method of the above embodiment.

The obtaining unit 801 may be configured to obtain a theoretical output voltage of the first converter according to a voltage of the source terminal, and the obtaining unit 801 is further configured to obtain a theoretical input voltage of the second converter according to a voltage of the destination terminal.

Wherein the source terminal is one of a battery and a power grid. The destination terminal is the other of the battery and the power grid. The source end transmits electric energy to the destination end through the first converter and the second converter in sequence.

The processing unit 802 may be configured to set an actual output voltage of the first converter during the first power supply period based on the theoretical output voltage of the first converter and the theoretical input voltage of the second converter.

The first power supply period is the current period of transmitting electric energy from the source end to the destination end.

The actual output voltage of the first converter in the current period is set by comprehensively considering the theoretical output voltage of the first converter and the theoretical input voltage of the second converter. The actual output voltage of the first converter in the current period can be timely adjusted according to the voltage of the source terminal and the voltage of the destination terminal, and the control of the power converter improves the energy transmission efficiency between the source terminal and the destination terminal.

Moreover, as the energy transmission efficiency between the source end and the destination end is improved, the problem that the energy of conversion failure caused by low energy transmission efficiency is consumed in a heat form is avoided, so that adverse effects on the component elements of the first converter and the component elements of the second converter caused by heat consumption are avoided, the service lives of the first converter and the second converter are prolonged, and the working performance of the first converter and the second converter is improved.

The following description will take a source terminal as a battery and a destination terminal as a power grid as an example.

In one implementation, the processing unit 802 is configured to: if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than the minimum operating voltage of the second converter and smaller than the maximum bearing voltage of the first converter and the second converter, the larger value is set as the actual output voltage of the first converter in the first power supply period.

In one implementation, the processing unit 802 is configured to: and if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than the minimum working voltage of the second converter and smaller than the maximum bearing voltage of the first converter and the second converter, and the absolute value of the difference value of the actual output voltage of the first converter in the second power supply period is smaller than or equal to a first voltage threshold value, setting the larger value as the actual output voltage of the first converter in the first power supply period, wherein the second power supply period is the previous period of the first power supply period.

In one implementation, the processing unit 802 is configured to: and if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than the minimum working voltage of the second converter and smaller than the maximum bearing voltage of the first converter and the second converter, and the absolute value of the difference value between the larger value and the actual output voltage of the first converter in the second power supply period is larger than a first voltage threshold value, setting the actual output voltage of the first converter in the first power supply period according to the actual output voltage of the first converter in the second power supply period and the first voltage threshold value, wherein the second power supply period is the period before the first power supply period.

In one implementation, the processing unit 802 is configured to: and if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is smaller than or equal to the minimum working voltage of the second converter, setting the minimum working voltage of the second converter as the actual output voltage of the first converter in the first power supply period.

In one implementation, the processing unit 802 is configured to: and if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than or equal to the maximum bearing voltage of the first converter and the second converter, setting the maximum bearing voltage of the first converter and the second converter as the actual output voltage of the first converter in the first power supply period.

In one implementation, the obtaining unit 801 is configured to: obtaining a theoretical output voltage of the first converter according to the voltage of the battery and the turn ratio of the first converter; the acquisition unit 801 is further configured to: and obtaining the theoretical input voltage of the second converter according to the voltage of the power grid and the maximum modulation ratio of the second converter.

The following description will take a source terminal as a power grid and a destination terminal as a battery as an example.

In one implementation, the processing unit 802 is configured to: if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than the minimum operating voltage of the first converter and smaller than the maximum bearing voltage of the first converter and the second converter, the larger value is set as the actual output voltage of the first converter in the first power supply period.

In one implementation, the processing unit 802 is further configured to: and if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than the minimum working voltage of the first converter and smaller than the maximum bearing voltage of the first converter and the second converter, and the absolute value of the difference value between the larger value and the actual output voltage of the first converter in the second power supply period is smaller than or equal to a second voltage threshold value, setting the larger value as the actual output voltage of the first converter in the first power supply period, wherein the second power supply period is the previous period of the first power supply period.

In one implementation, the processing unit 802 is further configured to: and if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is smaller than or equal to the minimum working voltage of the first converter, setting the minimum working voltage of the first converter as the actual output voltage of the first converter in the first power supply period.

In one implementation, the processing unit 802 is further configured to: the processing unit is used for: and if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than or equal to the maximum bearing voltage of the first converter and the second converter, setting the maximum bearing voltage of the first converter and the second converter as the actual output voltage of the first converter in the first power supply period.

In one implementation, the processing unit 802 is further configured to: obtaining theoretical output voltage of the first converter according to the voltage of the power grid and the maximum modulation ratio of the first converter; obtaining a theoretical input voltage of the second converter according to the voltage of the destination terminal, wherein the theoretical input voltage comprises the following steps: and obtaining the theoretical input voltage of the second converter according to the voltage of the battery and the turn ratio of the second converter.

It should be understood that, for brevity, specific implementation manner of the control device of the power converter and the resulting beneficial effects may be referred to the related description in the method embodiment, and will not be repeated.

The embodiment of the application also provides a control system of the power converter, which comprises an acquisition unit and a processing unit, and is used for executing the method of the embodiment.

Fig. 9 is a schematic hardware structure diagram of a control device of a power converter according to an embodiment of the present application. As shown in fig. 9, the control device 900 of the power converter includes a memory 901 and a processor 902, wherein the memory 901 is used for storing instructions, and the processor 902 is used for reading the instructions and executing the method based on the instructions.

In one example, the processor 902 may be a central processing unit (Central Processing Unit, CPU), or an application specific integrated circuit (Application Specific Integrated Circuit, ASIC), or may be configured as one or more integrated circuits implementing embodiments of the present application.

Memory 901 may include mass storage for data or instructions. By way of example, and not limitation, memory 901 may include a floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or universal serial bus (Universal Serial Bus, USB) drive, or a combination of two or more of these. Memory 901 may include removable or non-removable (or fixed) media where appropriate. The memory 901 may, where appropriate, be internal or external to the control device 900 of the power converter at the terminal hot spot. In a particular embodiment, the memory 901 is a non-volatile solid state memory. In a particular embodiment, the Memory 901 includes Read-Only Memory (ROM). The ROM may be mask-programmed ROM, programmable ROM (Programmable Read-Only Memory, PROM), erasable PROM (Erasable Programmable Read-Only Memory, EPROM), electrically erasable PROM (Electrically Erasable Programmable Read-Only Memory, EEPROM), electrically rewritable ROM (Electrically Alterable Read-Only Memory, EAROM), or flash Memory, or a combination of two or more of the above, where appropriate.

Control of the power converter in one example, the control device 900 of the power converter may further comprise a communication interface 903 and a bus 904. As shown in fig. 9, the memory 901, the processor 902, and the communication interface 903 are connected to each other via a bus 904 and perform communication with each other.

The communication interface 903 is mainly used to implement communication between each module, device, unit, and/or apparatus in the embodiment of the present application. Input devices and/or output devices may also be accessed through communication interface 903.

Bus 904 includes hardware, software, or both, coupling the components of control device 900 of the power converter to each other. By way of example, and not limitation, the Bus 904 may include an accelerated graphics port (Accelerated Graphics Port, AGP) or other graphics Bus, an enhanced industry standard architecture (Enhanced Industry Standard Architecture, EISA) Bus, a Front Side Bus (FSB), a HyperTransport (HT) interconnect, an industry standard architecture (Industry Standard Architecture, ISA) Bus, an Infiniband interconnect, a low pin count Bus, a memory Bus, a micro channel architecture (MCa) Bus, a Peripheral Component Interconnect (PCI) Bus, a PCI-Express (PCI-X) Bus, a Serial Advanced Technology Attachment (SATA) Bus, a video electronics standards Association local (VLB) Bus, or other suitable Bus, or a combination of two or more of these. Bus 904 may include one or more buses, where appropriate. Although embodiments of the application have been described and illustrated with respect to a particular bus, the application contemplates any suitable bus or interconnect.

The embodiment of the present application also provides a computer readable storage medium, on which a program or instructions are stored, which when executed by a processor, can implement the control method of the power converter in the above embodiment.

It should be understood that, in the present specification, each embodiment is described in an incremental manner, and the same or similar parts between the embodiments are all referred to each other, and each embodiment is mainly described in a different point from other embodiments. For apparatus embodiments, device embodiments, and computer-readable storage medium embodiments, references may be made to the description of method embodiments. The application is not limited to the specific steps and structures described above and shown in the drawings. Those skilled in the art will appreciate that various alterations, modifications, and additions may be made, or the order of steps may be altered, after appreciating the spirit of the present application. Also, a detailed description of known method techniques is omitted here for the sake of brevity.

Those skilled in the art will appreciate that the above-described embodiments are exemplary and not limiting. The different technical features presented in the different embodiments may be combined to advantage. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in view of the drawings, the description, and the claims. In the claims, the term "comprising" does not exclude other means or steps; the word "a" does not exclude a plurality; the terms "first," "second," and the like, are used for designating a name and not for indicating any particular order. Any reference signs in the claims shall not be construed as limiting the scope. The functions of the various elements presented in the claims may be implemented by means of a single hardware or software module. The presence of certain features in different dependent claims does not imply that these features cannot be combined to advantage.

Claims

1. A method of controlling a power converter, the method comprising:

obtaining theoretical output voltage of the first converter according to the voltage of the power grid;

acquiring theoretical input voltage of a second converter according to the voltage of a battery, wherein the power grid transmits electric energy to the battery through the first converter and the second converter in sequence;

setting an actual output voltage of the first converter in a first power supply period according to a theoretical output voltage of the first converter and a theoretical input voltage of the second converter, wherein the first power supply period is a current period of the power grid for transmitting electric energy to the battery;

the setting the actual output voltage of the first converter in the first power supply period according to the theoretical output voltage of the first converter and the theoretical input voltage of the second converter specifically includes:

if a larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than the minimum working voltage of the first converter and smaller than the maximum bearing voltage of the first converter and the second converter, and the absolute value of the difference value between the larger value and the actual output voltage of the first converter in a second power supply period is smaller than or equal to a second voltage threshold value, setting the larger value as the actual output voltage of the first converter in the first power supply period, wherein the second power supply period is a period before the first power supply period;

And if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than the minimum working voltage of the first converter and smaller than the maximum bearing voltage of the first converter and the second converter, and the absolute value of the difference value between the larger value and the actual output voltage of the first converter in the second power supply period is larger than a second voltage threshold value, setting the actual output voltage of the first converter in the first power supply period according to the actual output voltage of the first converter in the second power supply period and the second voltage threshold value, wherein the second power supply period is the previous period of the first power supply period.

2. The method of claim 1, wherein the method further comprises:

and if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is smaller than or equal to the minimum working voltage of the first converter, setting the minimum working voltage of the first converter as the actual output voltage of the first converter in a first power supply period.

3. The method of claim 1, wherein the method further comprises:

And if the larger value of the theoretical output voltage of the first converter and the theoretical input voltage of the second converter is larger than or equal to the maximum bearing voltage of the first converter and the second converter, setting the maximum bearing voltage of the first converter and the second converter as the actual output voltage of the first converter in a first power supply period.

4. A method according to any one of claims 1 to 3, wherein said deriving a theoretical output voltage of the first converter from the voltage of the grid comprises:

obtaining a theoretical output voltage of the first converter according to the voltage of the power grid and the maximum modulation ratio of the first converter;

the obtaining the theoretical input voltage of the second converter according to the voltage of the battery comprises the following steps:

and obtaining the theoretical input voltage of the second converter according to the voltage of the battery and the turn ratio of the second converter.

5. A control device for a power converter, the device comprising:

the power grid is used for transmitting electric energy to the battery through the first converter and the second converter in sequence;

The processing unit is used for setting the actual output voltage of the first converter in a first power supply period according to the theoretical output voltage of the first converter and the theoretical input voltage of the second converter, wherein the first power supply period is the current period of the power grid for transmitting electric energy to the battery;

the processing unit is specifically configured to:

6. The apparatus of claim 5, wherein the processing unit is further to:

7. The apparatus of claim 5, wherein the processing unit is further to:

8. The apparatus according to any one of claims 5 or 7, wherein the acquisition unit is specifically configured to:

9. A computer readable storage medium having stored thereon a program or instructions which, when executed by a processor, implements a method of controlling a power converter according to any one of claims 1 to 4.