CN115714537B

CN115714537B - Power converter, control method and power conversion system

Info

Publication number: CN115714537B
Application number: CN202211533615.1A
Authority: CN
Inventors: 王昊; 王宸阳; 黄成成
Original assignee: Suzhou Renogy New Energy Technoogy Co ltd
Current assignee: Suzhou Renogy New Energy Technoogy Co ltd
Priority date: 2022-12-02
Filing date: 2022-12-02
Publication date: 2023-04-18
Anticipated expiration: 2042-12-02
Also published as: CN115714537A

Abstract

The embodiment of the invention discloses a power converter, a control method and a power conversion system. The power converter comprises a plurality of independent DC/DC conversion modules connected in parallel, and each independent DC/DC conversion module connected in parallel comprises at least one slave module; the slave module comprises: the first communication module is used for acquiring a target output voltage of the power converter, the number of independent DC/DC conversion modules needing to be started and a current amplitude limiting value; the first output current sampling module is used for acquiring the output current value of the slave module; the first inductance current sampling module is used for acquiring the inductance current value of the slave module; and the current-sharing control module is used for adjusting the duty ratio of a driving signal of at least one switching tube in the slave module according to the target output voltage, the number of independent DC/DC conversion modules needing to be started, the current limiting value, the output current value of the slave module and the inductance current value of the slave module so as to enable the output current of the slave module to be equal to the current limiting value.

Description

Power converter, control method and power conversion system

Technical Field

The embodiment of the invention relates to the technical field of power converter control, in particular to a power converter, a control method and a power conversion system.

Background

At present, a power supply circuit is designed in a mode of connecting a plurality of DC-DC converters in parallel, and two control strategies for the DC-DC converters are mainly adopted. In one implementation, a unified main control unit may be provided, and the main control unit may automatically control one or more DC-DC converters to operate according to the magnitude of the system current, so as to complete the conversion task of the DC input power. For example, the master control unit may share the system current among the plurality of DC-DC converters according to the magnitude of the system current. In this case, since only the main control unit has the MCU, each DC-DC converter must operate under the control of the main control unit, and cannot operate independently, resulting in low system flexibility.

In another implementation mode, a power supply circuit is designed in a mode that a plurality of DC-DC converter chips are connected in parallel, but a sampling module is required to collect the voltage or the current of the total input end or the total output end of a plurality of paths of DC-DC converters connected in parallel, and then each DC-DC converter is controlled according to a voltage or current signal. Although the current sharing among each DC-DC converter can be realized in the mode, each DC-DC converter is controlled depending on the voltage or the current of the total input end or the total output end, and when each DC-DC converter is disassembled for use, the voltage or the current of the total input end or the total output end cannot be sampled, so that the DC-DC converters cannot work independently, and the advantage of parallel connection of a plurality of DC-DC converters is difficult to fully exert. In addition, the control strategy needs a sampling module to collect the voltage or the current of the total input end or the total output end of the multipath parallel DC-DC converter, and extra hardware cost is increased.

The foregoing description is provided for general background information and does not necessarily constitute prior art.

Disclosure of Invention

Embodiments of the present invention provide a power converter, a control method, and a power conversion system, which can implement independent control of each independent DC/DC conversion module without sampling a voltage or a current at a total input terminal or a total output terminal, retain an advantage that each independent DC/DC conversion module can be detached and used independently, reduce redundancy among each DC/DC conversion module, and reduce hardware cost of the power converter.

To this end, in a first aspect, an embodiment of the present invention provides a power converter, which includes multiple parallel independent DC/DC conversion modules, where the multiple parallel independent DC/DC conversion modules include at least one slave module; the slave module includes:

the first communication module is used for acquiring a target output voltage of the power converter, the number of independent DC/DC conversion modules needing to be started and a current amplitude limiting value;

the first output current sampling module is used for acquiring the output current value of the slave module;

the first inductance current sampling module is used for acquiring the inductance current value of the slave module;

and the current-sharing control module is used for adjusting the duty ratio of a driving signal of at least one switching tube in the slave module according to the target output voltage, the number of the independent DC/DC conversion modules needing to be started, the current limiting value, the output current value of the slave module and the inductance current value of the slave module so as to enable the output current of the slave module to be equal to the current limiting value.

Optionally, the current sharing control module includes:

a first voltage outer loop control unit, configured to determine a first current reference value according to the target output voltage, the number of independent DC/DC conversion modules that need to be started, and an output current value of the slave module;

the first amplitude limiting unit is used for determining a first current amplitude limiting reference value after processing the first current reference value according to the current amplitude limiting value;

and the first current inner loop control unit is used for determining the duty ratio of a driving signal of at least one switching tube in the slave module according to the first current amplitude limiting reference value and the inductance current value of the slave module.

Optionally, the first voltage outer loop control unit is configured to perform PI adjustment on a difference between the output current value of the slave module and a ratio of the target output voltage to the number of independent DC/DC conversion modules to be started, where the output current value of the slave module is used as a negative feedback quantity, and determine the first current reference value;

and the first current inner loop control unit is used for performing PI regulation on a difference value between the inductance current value of the slave module and the first current amplitude limiting reference value by taking the inductance current value of the slave module as a negative feedback quantity, and determining the duty ratio of a driving signal of at least one switching tube in the slave module.

Optionally, the multi-stage parallel independent DC/DC conversion module further includes a master module connected in parallel with the at least one slave module; the main module includes:

the second communication module is used for acquiring a target output voltage and the current limiting value of the power converter;

the first output voltage sampling module is used for acquiring the output voltage value of the main module;

the second inductive current sampling module is used for acquiring the inductive current value of the main module;

and the voltage stabilization control module is used for adjusting the duty ratio of a driving signal of at least one switching tube in the main module according to the target output voltage, the current limiting value, the output voltage value of the main module and the inductance current value of the main module, so that the output voltage of the main module is equal to the target output voltage.

Optionally, the voltage stabilization control module includes:

the second voltage outer ring control unit is used for determining a second current reference value according to the target output voltage and the output voltage value of the main module;

the second amplitude limiting unit is used for processing the second current reference value according to the current amplitude limiting value and then determining a second current amplitude limiting reference value;

and the second current inner loop control unit is used for determining the duty ratio of a driving signal of at least one switching tube in the main module according to the second current amplitude limiting reference value and the inductance current value of the main module.

Optionally, the second voltage outer loop control unit is configured to perform PI adjustment on a difference between the output voltage value of the main module and the target output voltage by using the output voltage value of the main module as a negative feedback quantity, and determine the second current reference value;

the second current inner loop control unit is configured to perform PI adjustment on a difference between the inductor current value of the main module and the second current limiting reference value by using the inductor current value of the main module as a negative feedback quantity, and determine a duty ratio of a driving signal of at least one switching tube in the main module.

Optionally, the current limiting values corresponding to each of the independent DC/DC conversion modules are the same;

when the number of the independent DC/DC conversion modules needing to be started is 1, the current limiting value is equal to the maximum current value allowed by the independent DC/DC conversion modules;

when the number of the independent DC/DC conversion modules needing to be started is greater than 1, the current limiting value is equal to target output power/(target output voltage) × the number of the independent DC/DC conversion modules needing to be started).

Optionally, the number of the independent DC/DC conversion modules to be started is determined according to the target output power and the rated power of the independent DC/DC conversion modules.

In a second aspect, embodiments of the present invention further provide a control method for a power converter, where the power converter includes multiple parallel independent DC/DC conversion modules, and the multiple parallel independent DC/DC conversion modules include at least one slave module; the control method comprises the following steps:

each slave module receives a target output voltage of the power converter configured by an upper computer, the number of independent DC/DC conversion modules needing to be started and a current amplitude limiting value;

each slave module acquires an output current value of the slave module and an inductance current value of the slave module;

each slave module adjusts the duty ratio of a driving signal of at least one switching tube in the slave module according to the target output voltage, the number of independent DC/DC conversion modules needing to be started, the current limiting value, the output current value of the slave module and the inductance current value of the slave module, so that the output current of the slave module is equal to the current limiting value.

In a third aspect, an embodiment of the present invention further provides a power conversion system, including: the control method comprises the steps of a battery, a power converter and a load, wherein the power converter is configured to execute the control method provided by any embodiment of the invention so that the battery provides energy for the load through the power converter.

As described above, the power converter disclosed in the embodiment of the present invention is formed by connecting multiple stages of independent DC/DC conversion modules in parallel, where the multiple stages of independent DC/DC conversion modules connected in parallel include at least one slave module, the slave module includes a first communication module capable of obtaining a target output voltage of the power converter, the number of independent DC/DC conversion modules to be started, and a current limiting value, a first output current sampling module capable of obtaining an output current value of the slave module, a first inductance current sampling module capable of obtaining an inductance current value of the slave module, and a current balancing control module capable of adjusting a duty ratio of a driving signal of at least one switching tube in the slave module according to the target output voltage, the number of independent DC/DC conversion modules to be started, the current limiting value, the output current value of the slave module, and the inductance current value of the slave module, so as to make the output current of the slave module equal to the current limiting value. Therefore, each slave module can independently regulate and control the output current of the slave module without sampling the voltage or the current of the master input end or the master output end, and the redundancy among the independent DC/DC conversion modules is reduced, so that each independent DC/DC conversion module of the power converter with the multistage independent DC/DC conversion modules connected in parallel can be separated and independently used. Compared with the DC/DC conversion module in the power converter in the prior art, the independent DC/DC conversion module in the scheme does not need to sample the total output current or voltage of the power converter in the process of adjusting and controlling the output current of the independent DC/DC conversion module, so that a related function module for sampling the total current or voltage by the power converter is not needed to be designed, and the hardware cost for designing the power converter is reduced.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a power converter according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of another power converter according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a slave module according to an embodiment of the present invention;

fig. 4 is a circuit diagram of a four-switch Buck-Boost power conversion module according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of another slave module according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a main module according to an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of another main module according to an embodiment of the present invention;

FIG. 8 is a flow chart illustrating a method for controlling a power converter according to an embodiment of the present invention;

FIG. 9 is a schematic diagram illustrating a control flow of each slave module in the power converter according to an embodiment of the present invention;

FIG. 10 is a flow chart illustrating another method for controlling a power converter according to an embodiment of the present invention;

FIG. 11 is a schematic diagram illustrating a control flow of a main module in a power converter according to an embodiment of the present invention;

FIG. 12 is a flow chart illustrating another method for controlling a power converter according to an embodiment of the present invention;

FIG. 13 is a schematic diagram of the total current output of a power converter according to an embodiment of the present invention;

FIG. 14 is a schematic diagram of the current output of a master/slave module according to an embodiment of the present invention;

fig. 15 is a schematic structural diagram of a power conversion system according to an embodiment of the present invention.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

It should be noted that, 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 phrases "comprising a component of' ...does not exclude the presence of another like element in a process, method, article, or apparatus that comprises the element. It will be further understood that, as used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context indicates otherwise. Also, as used herein, the terms "or," "and/or," "including at least one of the following," and the like, may be construed as being inclusive or meaning any one or any combination. An exception to this definition will occur only when a combination of elements, functions, steps or operations are inherently mutually exclusive in some way.

It should be understood that although the terms first, second, third, etc. may be used herein to describe various parameters or modules, these parameters or modules should not be limited by these terms. These terms are only used to distinguish one type of parameter or module from another. For example, a first parameter may also be referred to as a second parameter, and similarly, a second parameter may also be referred to as a first parameter, without departing from the scope herein. The words "if", as used herein may be interpreted as "at ...whenor" when ...when or "in response to a determination" or "in response to a detection", depending on the context. Similarly, the phrases "if determined" or "if detected (a stated condition or event)" may be interpreted as "when determined" or "in response to a determination" or "when detected (a stated condition or event)" or "in response to a detection (a stated condition or event)", depending on the context. Furthermore, the components, features and elements that have the same designation in different embodiments of the application may have the same meaning or may have different meanings, the specific meaning of which is to be determined by its explanation in the specific embodiment or further by its context in the specific embodiment.

It should be understood that, although the steps in the flowcharts in the embodiments of the present application are shown in sequence as indicated by the arrows, the steps are not necessarily performed in sequence as indicated by the arrows. The steps are not performed in the exact order shown and may be performed in other orders unless explicitly stated herein. Moreover, at least some of the steps in the figures may include multiple sub-steps or multiple stages that are not necessarily performed at the same time, but may be performed at different times, in different orders, and may be performed alternately or at least partially with respect to other steps or sub-steps of other steps.

It should be understood that the specific embodiments described herein are merely illustrative of the present application and do not limit the scope of the claims herein.

Fig. 1 is a schematic structural diagram of a power converter according to an embodiment of the present invention, fig. 2 is a schematic structural diagram of another power converter according to an embodiment of the present invention, fig. 3 is a schematic structural diagram of a slave module according to an embodiment of the present invention, and referring to fig. 1 to fig. 3, a power converter 01 includes a plurality of independent DC/DC conversion modules 100 connected in parallel, and each independent DC/DC conversion module 100 connected in parallel includes at least one slave module 110; the slave module 110 includes: the first communication module 111 is configured to obtain a target output voltage of the power converter 01, the number of independent DC/DC conversion modules that need to be started, and a current clipping value; a first output current sampling module 112, configured to obtain an output current value of the slave module 110; a first inductor current sampling module 113, configured to obtain an inductor current value of the slave module 110; and the current-sharing control module 114 is configured to adjust a duty ratio of a driving signal of at least one switching tube in the slave module 110 according to the target output voltage, the number of independent DC/DC conversion modules that need to be started, the current-limiting value, the output current value of the slave module 110, and the inductance current value of the slave module 110, so that the output current of the slave module 110 is equal to the current-limiting value.

In this embodiment, the power converter 01 is formed by connecting a plurality of independent DC/DC conversion modules 100 in parallel, and the power converter 01 may convert input power into other types of power, for example, convert direct current having a first voltage into direct current having a second voltage, which may be greater than or less than the first voltage. The plurality of independent DC/DC conversion modules 100 may jointly adjust the output power of the power converter 01 in a parallel use mode, and the power converter 01 may have a larger conversion power by putting a greater number of independent DC/DC conversion modules 100 into a parallel operation state, so as to meet the requirements for different power conversions in specific application occasions. Meanwhile, each independent DC/DC conversion module 100 in the power converter 01 has the advantage of being detachable for independent use, that is, each independent DC/DC conversion module 100 can be detached to operate as the power converter 01 in an independent use mode, so that the application scenarios and the use flexibility of the independent DC/DC conversion module 100 can be widened. In some specific application scenarios, users have demands for increasing power conversion power and improving stability of power conversion. Taking a solar controller as an example, assuming that the power of an original photovoltaic panel is 500W, a user can use only one 500W independent DC/DC conversion module 100 to perform power conversion; then, the user adds a new photovoltaic panel to change the system power to 800W, and at this time, the user can add another 500W independent DC/DC conversion module 100 to be connected with the previous independent DC/DC conversion module 100 in parallel to form a 1000W power converter 01 for power conversion. Thus, each independent DC/DC conversion module 100 can maintain flexibility of independent operation and control while supporting parallel use to meet different power conversion requirements. It should be noted that, in this embodiment, the parallel connection of the multiple independent DC/DC conversion modules 100 may be an input-parallel-output-parallel (IPOP), an input-series-output-parallel (ISOP), or an input-parallel-output-series (IPOP), and preferably, the multiple independent DC/DC conversion modules 100 in this embodiment are cascaded in an input-parallel-output-parallel (IPOP) manner to form the power converter 01.

Optionally, any number of slave modules 110 may be included in the multi-stage parallel independent DC/DC conversion module 100 to increase the total output power of the power converter 01. Each slave module 110 in the independent DC/DC conversion modules 100 connected in parallel in multiple stages can independently control and adjust the output current thereof, so that the slave module 110 in the independent DC/DC conversion modules 100 connected in parallel in multiple stages has the advantage of being detachable and independently used, thereby widening the application scenarios of the independent DC/DC conversion modules 100. Preferably, the output currents of all the independent DC/DC conversion modules 100 in the power converter 01 are controlled to be the same, that is, the current output by each independent DC/DC conversion module 100 is balanced, so that each independent DC/DC conversion module 100 can keep approximately the same use load and aging degree, thereby prolonging the service life of the power converter 01.

Optionally, at least one master module 120 and at least one slave module 110 are configured in the independent DC/DC conversion modules 100 connected in parallel in multiple stages, wherein the master module 120 may be any one of the independent DC/DC conversion modules 100 connected in parallel in multiple stages, and the remaining independent DC/DC conversion modules 100 are configured as the slave modules 110. In the control process, each slave module 110 is used for adjusting the output current balance of each independent DC/DC conversion module 100, and the master module 120 is used for controlling the output voltage of the stable DC bus.

In this embodiment, each slave module 110 includes a first communication module 111, a first output current sampling module 112, a first inductor current sampling module 113, a current sharing control module 114, and a first power conversion module 115. The first communication module 111, the first output current sampling module 112, and the first inductor current sampling module 113 are all connected to a current sharing control module 114. The first output current sampling module 112 and the first inductor current sampling module 113 are further connected to the first power conversion module 115, and are configured to obtain parameters of the first power conversion module 115. The output end of the current sharing control module 114 is connected to the first power conversion module 115, and is configured to output a driving signal to the first power conversion module 115.

The first power conversion module 115 is a DC/DC power conversion circuit, such as a Buck circuit, a Boost circuit, a Buck-Boost circuit, a Cuk circuit, or a Sepic circuit, and as a common feature, the DC/DC power conversion circuit includes at least one switching tube and an inductor. Preferably, in order to adapt to a wider bus input voltage range, the DC/DC power conversion circuit in the present embodiment employs a Buck-Boost circuit. More preferably, the DC/DC power conversion circuit in this embodiment adopts a four-switch Buck-Boost power conversion circuit. Fig. 4 is a circuit diagram of a four-switch Buck-Boost power conversion circuit according to an embodiment of the present invention, as shown in fig. 4, the four-switch Buck-Boost power conversion circuit at least includes a first capacitor C1, a first switch tube S1, a second switch tube S2, an inductor L, a third switch tube S3, a fourth switch tube S4, and a second capacitor C2, a voltage on the first capacitor C1 is an input voltage, the first capacitor C1, the first switch tube S1, and the second switch tube S2 form a series circuit, the third switch tube S3, the fourth switch tube S4, and the second capacitor C2 form a series circuit, a voltage on the second capacitor C2 is an output voltage, and the second switch tube S2, the inductor L, and the third switch tube S3 form a series circuit.

The first output current sampling module 112 may be a current sampling circuit or a current sensor for collecting an output current value of the slave module 110; specifically, the first output current sampling module 112 is connected to the first power conversion module 115, and is configured to collect an output current of the first power conversion module 115; more specifically, when the first power conversion module 115 is a four-switch Buck-Boost power conversion circuit, the first output current sampling module 112 may sample a current value at an output terminal of the second capacitor C2.

The first inductor current sampling module 113 may be a current sampling circuit or a current sensor, which is used for acquiring the inductor current value of the slave module 110; specifically, the first inductor current sampling module 113 is connected to the first power conversion module 115, and is configured to collect an inductor current of the first power conversion module 115; more specifically, when the first power conversion module 115 is a four-switch Buck-Boost power conversion circuit, the first inductor current sampling module 113 may sample a current value of the inductor L.

The current sharing control module 114 may be a microprocessor MCU of the slave module 110, and is connected to the first communication module 111, the first output current sampling module 112, and the first inductor current sampling module 113, and configured to adjust a duty ratio of a driving signal of at least one switching tube in the slave module 110 according to parameters given by the first communication module 111, the first output current sampling module 112, and the first inductor current sampling module 113. Specifically, the current share control module 114 may generate a PWM driving signal with a specific duty cycle and/or frequency and provide the PWM driving signal to at least one switching tube in the first power conversion module 115, so that the switching tube is periodically turned on and off according to the PWM driving signal, thereby changing the output current of the slave module 110. More specifically, when the first power conversion module 115 is a four-switch Buck-Boost power conversion circuit, the first switch tube S1 and the third switch tube S3 may use the same first PWM driving signal, the second switch tube S2 and the fourth switch tube S4 may use the same second PWM driving signal, and the first PWM driving signal and the second PWM driving signal are complementary to each other, so that the two sets of switch tubes are alternately turned on, thereby implementing synchronous rectification of the first power conversion module 115.

The first communication module 111 CAN be an RS485 module, a Bluetooth module, a CAN bus module and the like, and is communicated with an upper computer to obtain the target output voltage of the power converter 01, the number of independent DC/DC conversion modules to be started and the current limiting value from the upper computer. Specifically, the upper computer may be a controller that is communicatively connected to the power converter 01, a user may input demand parameters into the controller, and the controller may calculate a target output voltage, the number of independent DC/DC conversion modules that need to be started, and a current limiting value according to the demand parameters, and transmit the parameters to the first communication module 111 of each slave module 110 through the communication connection.

In this embodiment, the specific working process of each slave module 110 is as follows: the first communication module 111 performs information interaction with an upper computer, and obtains a target output voltage of the power converter 01 (a voltage which the power converter 01 needs to output, that is, a voltage which the power converter 01 needs to carry), the number of independent DC/DC conversion modules which need to be started (that is, the sum of the number of master/slave modules which need to be started), and a current limiting value (a maximum value of a current output by each independent DC/DC conversion module 100) through communication with the upper computer. The first output current sampling module 112 obtains the output current value of the slave module 110. The first inductor current sampling module 113 obtains the inductor current value of the slave module 110. After the current sharing control module 114 receives the target output voltage, the number of independent DC/DC conversion modules to be started, the current limit value, the output current value of the slave module 110, and the inductance current value of the slave module 110, which are obtained by the first communication module 111, the first output current sampling module 112, and the first inductance current sampling module 113, data processing is performed on the target output voltage, the number of independent DC/DC conversion modules to be started, the current limit value, the output current value of the slave module 110, and the inductance current value of the slave module 110 to adjust the duty ratio of the driving signal of at least one switching tube in the slave module 110, so that the output current of the slave module 110 is equal to the current limit value, and when the output current of each slave module 110 is equal to the current limit value, since the total output current of the power converter 01 is fixed, the output current of the master module 120 also automatically approaches the current limit value, thereby implementing balance control of the output current of each parallel independent DC/DC conversion module 100 in the power converter 01.

According to the working process of each slave module 110, the slave module 110 does not need to sample and acquire the voltage or current of the total input end or the total output end of the power converter 01, and each independent DC/DC conversion module 100 does not need to communicate with each other, and the communication module and the sampling module can independently adjust and control the output current of the slave module by acquiring the control parameters of the slave module, so that the redundancy among the independent DC/DC conversion modules 100 is reduced, and each independent DC/DC conversion module 100 of the power converter 01 with the multiple stages of independent DC/DC conversion modules 100 connected in parallel can be separated and used independently. In addition, compared with the DC/DC conversion module in the power converter 01 in the prior art, in the process of adjusting and controlling the output current of the independent DC/DC conversion module 100 according to the present embodiment, it is not necessary to sample the voltage or current (bus voltage or bus current) at the total input end or the total output end of the power converter 01, and therefore, it is not necessary to design a related function module for sampling the bus current or the bus voltage, and the hardware cost for designing the power converter 01 can be effectively reduced.

For example, on the basis of the above embodiments, fig. 5 is a schematic structural diagram of another slave module according to an embodiment of the present invention, and as shown in fig. 5, the current sharing control module 114 includes: a first voltage outer loop control unit 1141, configured to determine a first current reference value according to a target output voltage, the number of independent DC/DC conversion modules that need to be started, and an output current value of the slave module 110; the first amplitude limiting unit 1142 is configured to determine a first current amplitude limiting reference value after processing the first current reference value according to the current amplitude limiting value; and a first current inner loop control unit 1143, configured to determine a duty cycle of a driving signal of at least one switching tube in the slave module 110 according to the first current clipping reference value and an inductance current value of the slave module 110.

Specifically, the current sharing control module 114 includes a first voltage outer loop control unit 1141, a first amplitude limiting unit 1142, a first current inner loop control unit 1143, and a slave module driving signal generation unit 1144. The first communication module 111 and the first output current sampling module 112 are both connected to a first voltage outer loop control unit 1141, the first voltage outer loop control unit 1141 and the first communication module 111 are both connected to a first amplitude limiting unit 1142, the first amplitude limiting unit 1142 and the first inductive current sampling module 113 are both connected to a first current inner loop control unit 1143, and the first current inner loop control unit 1143 is connected to a slave module driving signal generation unit 1144.

The specific working process of the current-sharing control module 114 is as follows: the first voltage outer loop control unit 1141 obtains the target output voltage and the number of independent DC/DC conversion modules to be started through the first communication module 111. The first voltage outer loop control unit 1141 obtains the output current value of the slave module 110 through the first output current sampling module 112. Thus, the first voltage outer loop control unit 1141 performs data processing according to the target output voltage, the number of independent DC/DC conversion modules that need to be started, and the output current value of the slave module 110, thereby determining the first current reference value. The first amplitude limiting unit 1142 may obtain the current amplitude limiting value through the first communication module 111, and process the first current reference value output by the first voltage outer loop control unit 1141 according to the current amplitude limiting value, so as to obtain the first current amplitude limiting reference value. For example, when the first current reference value is greater than the current clipping value, the first clipping unit 1142 performs clipping processing on the first current reference value to make the first current reference value equal to the current clipping value, so as to obtain the first current clipping reference value equal to the current clipping value. When the first current reference value is smaller than the current clipping value, the first clipping unit 1142 does not process the first current reference value, so that the first current reference value is equal to the first current clipping reference value. The first current inner loop unit obtains a first current amplitude limiting reference value generated by the first amplitude limiting unit 1142 and an inductance current value of the slave module 110 acquired by the first inductance current sampling module 113, and may process the first current amplitude limiting reference value and the inductance current value of the slave module 110 to obtain a suitable duty ratio of the driving signal. The slave module driving signal generating unit 1144 may generate a PWM driving signal having a specific duty ratio and/or frequency according to the duty ratio of the driving signal and provide the PWM driving signal to at least one switching tube in the first power conversion module 115, so that the switching tube is periodically turned on and off according to the PWM driving signal, thereby changing the output current of the slave module 110.

Optionally, the first voltage outer loop control unit 1141 is configured to perform PI adjustment on a difference between the output current value of the slave module 110 and a ratio between the target output voltage and the number of independent DC/DC conversion modules to be started, where the negative feedback value is an output current value of the slave module, and determine a first current reference value; the first current inner loop control unit 1143 is configured to perform PI adjustment on a difference between the inductance current value of the slave module 110 and the first current limit reference value by using the inductance current value of the slave module as a negative feedback quantity, and determine a duty ratio of a driving signal of at least one switching tube in the slave module 110.

According to the connection relationship of the above functional components, the specific working process of each slave module 110 is further detailed as follows: the first communication module 111 performs information interaction with an upper computer, and obtains a target output voltage of the power converter 01, the number of independent DC/DC conversion modules to be started and a current limiting value through communication with the upper computer. The first output current sampling module 112 obtains the output current value of the slave module 110. The first communication module 111 outputs the target output voltage and the number of independent DC/DC conversion modules to be started to the first voltage outer loop control unit 1141, and the first output current sampling module 112 outputs the output current value of the slave module 110 to the first voltage outer loop control unit 1141. The first voltage outer loop control unit 1141 performs difference processing on a ratio of the received target output voltage and the output current value of the slave module 110 divided by the number of independent DC/DC conversion modules to be started, and performs PI adjustment on the obtained difference value to obtain a first current reference value. The first communication module 111 outputs the current amplitude limiting value to the first amplitude limiting unit 1142, the first voltage outer loop control unit 1141 outputs the first current reference value to the first amplitude limiting unit 1142, and the first amplitude limiting unit 1142 performs amplitude limiting on the first current reference value using the current amplitude limiting value as a standard to obtain a first current amplitude limiting reference value (the maximum current amplitude limiting value of the first current amplitude limiting reference value is the current amplitude limiting value). The first inductor current sampling module 113 may obtain an inductor current value of the slave module 110, and the first inductor current sampling module 113 outputs the inductor current value of the slave module 110 to the first current inner loop control unit 1143. The first clipping unit 1142 outputs the first current clipping reference value to the first current inner loop control unit 1143. The first current inner loop control unit 1143 may perform difference processing on the received first current clipping reference value and the inductance current value of the slave module 110, and perform PI adjustment on the obtained difference value to obtain a duty ratio of a driving signal of at least one switching tube in the slave module 110. The slave module driving signal generating unit 1144 generates a PWM driving signal having a specific duty ratio and/or frequency according to the duty ratio of the driving signal and provides the PWM driving signal to at least one switching tube in the first power conversion module 115, so that the switching tube is periodically turned on and off according to the PWM driving signal, thereby controlling the output current of the slave module 110 to be equal to the current limiting value, and implementing the control of the output current of the slave module 110.

Exemplarily, on the basis of the above embodiments, fig. 6 is a schematic structural diagram of a master module according to an embodiment of the present invention, and referring to fig. 1 and fig. 6, the independent DC/DC conversion module 100 further includes a master module 120 connected in parallel with at least one slave module 110; the main module 120 includes: the second communication module 121 is configured to obtain a target output voltage and a current limit value of the power converter 01; a first output voltage sampling module 122, configured to obtain an output voltage value of the main module 120; a second inductor current sampling module 123, configured to obtain an inductor current value of the main module 120; and the voltage stabilization control module 124 is configured to adjust a duty ratio of a driving signal of at least one switching tube in the main module 120 according to the target output voltage, the current limiting value, the output voltage value of the main module 120, and the inductance current value of the main module 120, so that the output voltage of the main module 120 is equal to the target output voltage.

Specifically, the master module 120 is mainly responsible for stabilizing the output voltage on the DC bus of the independent DC/DC conversion module 100, thereby controlling the voltage adjustment value of the slave module 110 connected in parallel therewith. The main module 120 includes a second communication module 121, a first output voltage sampling module 122, a second inductor current sampling module 123, a voltage regulation control module 124, and a second power conversion module 125. The second communication module 121, the first output voltage sampling module 122, and the second inductor current sampling module 123 are all connected to the voltage regulation control module 124. The first output voltage sampling module 122 and the second inductor current sampling module 123 are further connected to the second power conversion module 125, and are configured to obtain parameters of the second power conversion module 125. The output end of the voltage regulation control module 124 is connected to the second power conversion module 125, and is configured to output the driving signal to the second power conversion module 125.

The second power conversion module 125 is a DC/DC power conversion circuit, such as a Buck circuit, a Boost circuit, a Buck-Boost circuit, a Cuk circuit, or a Sepic circuit, and as a common feature, the DC/DC power conversion circuit includes at least one switching tube and an inductor. Preferably, in order to adapt to a wider bus input voltage range, the DC/DC power conversion circuit in the embodiment adopts a Buck-Boost circuit. More preferably, the DC/DC power conversion circuit in this embodiment adopts a four-switch Buck-Boost power conversion circuit. The four-switch Buck-Boost power conversion circuit is described in the above embodiments, and will not be described herein.

The first output voltage sampling module 122 may be a voltage sampling circuit or a voltage sensor, and is configured to collect an output voltage value of the main module 120; specifically, the first output voltage sampling module 122 is connected to the second power conversion module 125, and is configured to collect an output voltage of the second power conversion module 125; more specifically, with continued reference to fig. 4, when the second power conversion module 125 is a four-switch Buck-Boost power conversion circuit, the first output voltage sampling module 122 may sample a voltage value at the output terminal of the second capacitor C2.

The second inductor current sampling module 123 may be a current sampling circuit or a current sensor, and is configured to collect an inductor current value of the main module 120; specifically, the second inductor current sampling module 123 is connected to the second power conversion module 125, and is configured to collect an inductor current of the second power conversion module 125; more specifically, with continued reference to fig. 4, when the second power conversion module 125 is a four-switch Buck-Boost power conversion circuit, the second inductor current sampling module 123 may sample a current value of the inductor L.

The voltage regulation control module 124 may be a microprocessor MCU of the main module 120, and is connected to the second communication module 121, the first output voltage sampling module 122, and the second inductor current sampling module 123, and configured to adjust a duty ratio of a driving signal of at least one switching transistor in the main module 120 according to parameters provided by the second communication module 121, the first output voltage sampling module 122, and the second inductor current sampling module 123. Specifically, the voltage regulation control module 124 may generate a PWM driving signal having a specific duty ratio and/or frequency and provide the PWM driving signal to at least one switching tube in the second power conversion module 125, so that the switching tube is periodically turned on and off according to the PWM driving signal, thereby stabilizing the output voltage of the main module 120. More specifically, with continued reference to fig. 4, when the second power conversion module 125 is a four-switch Buck-Boost power conversion circuit, the first switch tube S1 and the third switch tube S3 may use the same first PWM driving signal, the second switch tube S2 and the fourth switch tube S4 may use the same second PWM driving signal, and the first PWM driving signal and the second PWM driving signal are complementary, so that the two groups of switch tubes are alternately turned on, thereby implementing synchronous voltage stabilization of the second power conversion module 125.

The second communication module 121 may be an RS485, bluetooth, CAN bus, or the like, and communicates with the upper computer to obtain a target output voltage and a current limit value of the power converter 01 from the upper computer. Specifically, the upper computer may be a controller that is communicatively connected to the power converter 01, and a user may input demand parameters into the controller, and the controller may calculate target output voltage and current limiting values according to the demand parameters and transmit the parameters to the second communication module 121 of the main module 120 through the communication connection.

In this embodiment, the specific working process of the main module 120 is as follows: the second communication module 121 performs information communication with an upper computer, and obtains a target output voltage (a voltage that the power converter 01 needs to output, that is, a voltage that the power converter 01 needs to carry) and a current limit value (a maximum value of a current output by each independent DC/DC conversion module 100) of the power converter 01 through the upper computer communication. The first output voltage sampling module 122 may obtain an output voltage value of the main module 120. The second inductor current sampling module 123 may obtain the inductor current value of the main module 120. The voltage stabilizing control module 124 may receive the target output voltage, the current limit value, the output voltage value of the main module 120, and the inductance current value of the main module 120 of the power converter 01 obtained by the second communication module 121, the first output voltage sampling module 122, and the second inductance current sampling module 123, and perform data processing on the target output voltage, the current limit value, the output voltage value of the main module 120, and the inductance current value of the main module 120 of the power converter 01, so as to adjust the duty ratio of the driving signal of at least one switching tube in the main module 120, so that the output voltage of the main module 120 is equal to the target output voltage, and further, the purpose of stabilizing the output voltage on the DC bus of the independent DC/DC conversion module 100 to be equal to the target output voltage is achieved.

For example, on the basis of the above embodiments, fig. 7 is a schematic structural diagram of another main module according to an embodiment of the present invention, and as shown in fig. 7, the voltage regulation control module 124 includes: a second voltage outer loop control unit 1241 for determining a second current reference value according to the target output voltage and the output voltage value of the main module 120; a second amplitude limiting unit 1242, configured to determine a second current amplitude limiting reference value after processing the second current reference value according to the current amplitude limiting value; the second current inner loop control unit 1243 is configured to determine a duty cycle of a driving signal of at least one switching tube in the main module 120 according to the second current limiting reference value and the inductor current value of the main module 120.

Specifically, the voltage stabilization control module 124 includes a second voltage outer loop control unit 1241, a second clipping unit 1242, a second current inner loop control unit 1243, and a main module driving signal generation unit 1244. The second communication module 121 and the first output voltage sampling module 122 are both connected to a second voltage outer-loop control unit 1241, the second communication module 121 and the second voltage outer-loop control unit 1241 are both connected to a second amplitude limiting unit 1242, the second amplitude limiting unit 1242 and the second inductor current sampling module 123 are both connected to a second current inner-loop control unit 1243, and the second current inner-loop control unit 1243 is connected to a main module driving signal generating unit 1244.

The specific working process of the voltage stabilization control module 124 is as follows: the second voltage outer loop control unit 1241 acquires the target output voltage through the second communication module 121. The second voltage outer loop control unit 1241 obtains the output voltage value of the main module 120 through the first output voltage sampling module 122. Thus, the second voltage outer loop control unit 1241 performs data processing according to the target output voltage and the output voltage value of the main module 120, thereby determining a second current reference value. The second amplitude limiting unit 1242 may obtain the current amplitude limiting value through the second communication module 121, and process the second current reference value output by the second voltage outer loop control unit 1241 according to the current amplitude limiting value, to obtain the second current amplitude limiting reference value. For example, when the second current reference value is greater than the current clipping value, the second clipping unit 1242 performs clipping processing on the second current reference value so that the second current reference value is equal to the current clipping value, thereby obtaining a second current clipping reference value equal to the current clipping value. When the second current reference value is smaller than the current clipping value, the second clipping unit 1242 does not process the second current reference value, so that the second current reference value is equal to the second current clipping reference value. The second current inner loop unit obtains a second current amplitude limiting reference value generated by the second amplitude limiting unit 1242 and an inductance current value of the main module 120 acquired by the second inductance current sampling module 123, and may process the second current amplitude limiting reference value and the inductance current value of the main module 120 to obtain a duty ratio of a driving signal and output the duty ratio of the driving signal to the main module driving signal generating unit 1244. The main module driving signal generating unit 1244 may generate a PWM driving signal having a specific duty ratio and/or frequency according to the duty ratio of the driving signal and provide the PWM driving signal to at least one switching tube in the second power conversion module 125, so that the switching tube is periodically turned on and off according to the PWM driving signal, thereby stabilizing the output voltage of the main module 120.

Optionally, the second voltage outer loop control unit 1241 is configured to perform PI adjustment on a difference between the output voltage value of the main module 120 and the target output voltage with the output voltage value of the main module as a negative feedback quantity, and determine a second current reference value; the second current inner loop control unit 1243 is configured to perform PI adjustment on a difference between the inductor current value of the main module 120 and the second current limit reference value, where the inductor current value is used as a negative feedback quantity, and determine a duty ratio of a driving signal of at least one switching tube in the main module 120.

According to the connection relationship of the above functional components, the specific working process of the main module 120 is further detailed as follows: the second communication module 121 performs information interaction with an upper computer, and obtains a target output voltage and a current amplitude limiting value of the power converter 01 through communication with the upper computer. The first output voltage sampling module 122 obtains an output voltage value of the main module 120. The second communication module 121 outputs the target output voltage to the second voltage outer ring control unit 1241, and the first output voltage sampling module 122 outputs the output voltage value of the main module 120 to the second voltage outer ring control unit 1241. The second voltage outer loop control unit 1241 performs difference processing on the output voltage value of the main module 120 and the target output voltage, and performs PI adjustment on the obtained difference value to obtain a second current reference value. The second communication module 121 outputs the current amplitude limiting value to the second amplitude limiting unit 1242, the second voltage outer ring control unit 1241 outputs the second current reference value to the second amplitude limiting unit 1242, and the second amplitude limiting unit 1242 performs amplitude limiting on the second current reference value by using the current amplitude limiting value as a standard to obtain a second current amplitude limiting reference value. The second inductor current sampling module 123 obtains an inductor current value of the main module 120, and the second inductor current sampling module 123 outputs the inductor current value of the main module 120 to the second current inner loop control unit 1243. The second clipping unit 1242 outputs the second current clipping reference value to the second current inner loop control unit 1243. The second current inner loop control unit 1243 may perform difference processing on the received second current limiting reference value and the inductance current value of the main module 120, and perform PI adjustment on the obtained difference value to obtain a duty ratio of a driving signal of at least one switching tube in the main module 120. The main module driving signal generating unit 1244 generates a PWM driving signal with a specific duty ratio and/or frequency according to the duty ratio of the driving signal and provides the PWM driving signal to at least one switching tube in the second power conversion module 125, so that the switching tube is periodically turned on and off according to the PWM driving signal, thereby controlling the output voltage of the main module 120 to be equal to the target output voltage, and stabilizing the output voltage on the DC bus of the independent DC/DC conversion module 100 at the target output voltage.

Optionally, the current limiting values corresponding to each independent DC/DC conversion module are the same; when the number of the independent DC/DC conversion modules needing to be started is 1, the current amplitude limiting value is equal to the maximum current value allowed by the independent DC/DC conversion modules; when the number of independent DC/DC conversion modules that need to be started is greater than 1, the current limit value is equal to the target output power/(target output voltage) × the number of independent DC/DC conversion modules that need to be started).

Specifically, when each independent DC/DC conversion module independently adjusts the current output of the power converter in the independent use mode, it indicates that the number of the independent DC/DC conversion modules that need to be started at this time is 1, the current limiting values corresponding to each independent DC/DC conversion module are the same, and the current limiting values are equal to the maximum current value allowed by the independent DC/DC conversion module.

When the plurality of independent DC/DC conversion modules can jointly adjust the current output of the power converter in the parallel use mode, it indicates that the number of the independent DC/DC conversion modules that need to be started is greater than 1, the current limit values corresponding to each independent DC/DC conversion module are the same, and the current limit value is equal to the target output power/(target output voltage) × the number of the independent DC/DC conversion modules that need to be started).

Illustratively, according to the design specification and the device type selection limitation requirement, it is assumed that the rated voltage of each DC/DC conversion module is 30V, the rated power is 300W, and the allowable maximum current value is 25A. When the number of independent DC/DC conversion modules needing to be started is 1, the upper computer can remove the limitation of the amplitude limiting value of the current inner ring reference value of each slave module and the master module, at the moment, the amplitude limiting value is equal to the allowed maximum current value, and the DC/DC conversion modules independently carry out power conversion without limiting the amplitude limitation unless the current value exceeds the allowed maximum current value of the DC/DC conversion modules.

For example, when the number of independent DC/DC conversion modules to be started is greater than 1, for example, the target output power (required power for loading) is 900W, and the target output voltage (required voltage for loading) is 30V, the number of independent DC/DC conversion modules to be started is 900W/300w =3, and the current limit value = 900W/(30v × 3) =10A, so that the current limit value of each independent DC/DC conversion module can be set to 10A.

Specifically, the number of independent DC/DC conversion modules that need to be started = target output power/rated power of the independent DC/DC conversion modules. Illustratively, when the target output power is 900W and the rated power of the independent DC/DC conversion module is 300W, the number of the independent DC/DC conversion modules to be started is 3.

Fig. 8 is a flowchart illustrating a control method of a power converter according to an embodiment of the present invention. The power converter comprises a plurality of independent DC/DC conversion modules which are connected in parallel, and each independent DC/DC conversion module which is connected in parallel comprises at least one slave module. As shown in fig. 8, the control method of the power converter specifically includes:

s210, each slave module receives a target output voltage of a power converter configured by the upper computer, the number of independent DC/DC conversion modules needing to be started and a current limiting value.

Specifically, the slave modules comprise first communication modules, the first communication modules can perform information interaction with an upper computer, and the target output voltage of the power converter, the number of independent DC/DC conversion modules to be started and the current limiting value can be obtained through communication with the upper computer.

And S220, each slave module acquires the output current value of the slave module and the inductance current value of the slave module.

Specifically, the slave module further comprises a first output current sampling module and a first inductor current sampling module, the first output current sampling module can acquire the output current value of the slave module, and the first inductor current sampling module can acquire the inductor current value of the slave module.

And S230, each slave module adjusts the duty ratio of a driving signal of at least one switching tube in the slave module according to the target output voltage, the number of independent DC/DC conversion modules needing to be started, the current limiting value, the output current value of the slave module and the inductance current value of the slave module, so that the output current of the slave module is equal to the current limiting value.

Specifically, the slave module further comprises a current sharing control module, and the current sharing control module can adjust the duty ratio of a driving signal of at least one switching tube in the slave module according to the target output voltage, the number of independent DC/DC conversion modules to be started, the current limiting value, the output current value of the slave module and the inductance current value of the slave module, so that the output current of the slave module is equal to the current limiting value.

As described above, the power converter disclosed in the embodiment of the present invention is formed by connecting multiple independent DC/DC conversion modules in parallel, where the multiple independent DC/DC conversion modules connected in parallel include at least one slave module, and each slave module can receive a target output voltage of the power converter configured by an upper computer, the number of independent DC/DC conversion modules to be started, and a current limit value; each slave module can also obtain the output current value of the slave module and the inductance current value of the slave module, and each slave module can also adjust the duty ratio of a driving signal of at least one switching tube in the slave module according to the target output voltage, the number of independent DC/DC conversion modules needing to be started, the current limiting value, the output current value of the slave module and the inductance current value of the slave module, so that the output current of the slave module is equal to the current limiting value. Therefore, each slave module can independently regulate and control the output current of the slave module without sampling the voltage or the current of the master input end or the master output end, and the redundancy among the DC/DC conversion modules is reduced, so that each independent DC/DC conversion module of the power converter with the multi-stage independent DC/DC conversion modules connected in parallel can be separated and independently used. Compared with the DC/DC conversion module in the power converter in the prior art, the independent DC/DC conversion module does not need to sample the total output current or voltage of the power converter in the process of adjusting and controlling the output current of the independent DC/DC conversion module, so that a related function module for sampling the total current or voltage by the power converter is not needed to be designed, and the hardware cost for designing the power converter is reduced.

Exemplarily, fig. 9 is a flowchart illustrating a method for each slave module to adjust a duty ratio of a driving signal of at least one switching transistor in the slave module according to a target output voltage, a number of independent DC/DC conversion modules to be started, a current limiting value, an output current value of the slave module, and an inductance current value of the slave module, where the method is further described in detail on the basis of the above embodiments:

and S310, taking the output current value of the slave module as a negative feedback quantity, carrying out PI regulation on the difference value between the output current value and the ratio of the target output voltage and the number of independent DC/DC conversion modules needing to be started, and determining a first current reference value.

Specifically, the current-sharing control module comprises a first voltage outer ring control unit, the first voltage outer ring control unit performs difference processing on a ratio of the received target output voltage and the output current value of the slave module divided by the number of independent DC/DC conversion modules needing to be started, and performs PI adjustment on an obtained difference value to obtain a first current reference value.

And S320, processing the first current reference value according to the current amplitude limiting value, and then determining the first current amplitude limiting reference value.

Specifically, the current-sharing control module further includes a first amplitude limiting unit, and the first amplitude limiting unit performs amplitude limiting on the first current reference value by using the current amplitude limiting value as a standard to obtain a first current amplitude limiting reference value.

S330, taking the inductance current value of the slave module as a negative feedback quantity, carrying out PI regulation on the difference value between the inductance current value of the slave module and the first current amplitude limiting reference value, and determining the duty ratio of a driving signal of at least one switching tube in the slave module.

Specifically, the current-sharing control module further comprises a first current inner loop control unit, the first current inner loop control unit can perform difference processing on the received first current amplitude limiting reference value and the inductance current value of the slave module, and perform PI adjustment on the obtained difference value to obtain the duty ratio of the driving signal of at least one switching tube in the slave module, so that the output current of the slave module is equal to the current amplitude limiting value, and further control over the output current of the slave module is achieved.

Optionally, the multi-stage parallel independent DC/DC conversion module further includes a master module connected in parallel with at least one slave module.

Fig. 10 is a schematic flow chart of another control method for a multi-power converter according to an embodiment of the present invention, and as shown in fig. 10, the method includes the following specific steps:

and S410, each slave module receives the target output voltage of the power converter configured by the upper computer, the number of independent DC/DC conversion modules needing to be started and the current limiting value.

And S420, each slave module acquires the output current value of the slave module and the inductance current value of the slave module.

And S430, each slave module adjusts the duty ratio of a driving signal of at least one switching tube in the slave module according to the target output voltage, the number of independent DC/DC conversion modules needing to be started, the current limiting value, the output current value of the slave module and the inductance current value of the slave module, so that the output current of the slave module is equal to the current limiting value.

And S440, receiving a target output voltage and a current amplitude limiting value of a power converter configured by the upper computer by the main module.

Specifically, the main module comprises a second communication module, the second communication module can perform information interaction with an upper computer, and the target output voltage and the current amplitude limiting value of the power converter can be obtained through communication with the upper computer.

S450, the main module obtains the output voltage value of the main module and the inductance current value of the main module.

Specifically, the main module further includes a first output voltage sampling module and a second inductor current sampling module, where the first output voltage sampling module may obtain an output voltage value of the main module, and the second inductor current sampling module may obtain an inductor current value of the main module.

And S460, the main module adjusts the duty ratio of a driving signal of at least one switching tube in the main module according to the target output voltage, the current limiting value, the output voltage value of the main module and the inductance current value of the main module, so that the output voltage of the main module is equal to the target output voltage.

Specifically, the main module further comprises a voltage stabilization control module, and the voltage stabilization control module can adjust the duty ratio of a driving signal of at least one switching tube in the main module according to the target output voltage, the current limiting value, the output voltage value of the main module and the inductance current value of the main module, so that the output voltage of the main module is equal to the target output voltage, and further the purpose of stabilizing the output voltage on the direct current bus of the independent DC/DC conversion module to be equal to the target output voltage is achieved.

It should be noted that, in the embodiment, although steps S410 to S430 and steps S440 to S460 are described in a sequential order, steps S410 to S430 and steps S440 to S460 may be performed in a power converter in a near or almost simultaneous manner, and there is no typical sequential order.

Exemplarily, fig. 11 is a flowchart illustrating a method for a main module to adjust a duty cycle of a driving signal of at least one switching transistor in the main module according to a target output voltage, a current limiting value, an output voltage value of the main module, and an inductance current value of the main module, which is further detailed on the basis of the above embodiments:

and S510, taking the output voltage value of the main module as a negative feedback quantity, carrying out PI regulation on the difference value between the output voltage value of the main module and the target output voltage, and determining a second current reference value.

Specifically, the voltage stabilization control module comprises a second voltage outer ring control unit, the second voltage outer ring control unit performs difference processing on the output voltage value of the main module and the target output voltage, and performs PI adjustment on the obtained difference value to obtain a second current reference value.

And S520, processing the second current reference value according to the current amplitude limiting value, and then determining the second current amplitude limiting reference value.

Specifically, the voltage stabilization control module further includes a second amplitude limiting unit, and the second amplitude limiting unit performs amplitude limiting on the second current reference value by using the current amplitude limiting value as a standard to obtain a second current amplitude limiting reference value.

And S530, taking the inductance current value of the main module as negative feedback quantity, carrying out PI regulation on the difference value between the inductance current value of the main module and the second current amplitude limiting reference value, and determining the duty ratio of a driving signal of at least one switching tube in the main module.

Specifically, the voltage stabilization control module further comprises a second current inner loop control unit, the second current inner loop control unit can perform difference processing on the received second current amplitude limiting reference value and the inductance current value of the main module, and perform PI adjustment on the obtained difference value to obtain the duty ratio of the driving signal of at least one switching tube in the module, so that the output voltage of the main module is equal to the target output voltage, and further the purpose of stabilizing the output voltage on the direct current bus of the independent DC/DC conversion module to be equal to the target output voltage is achieved.

Fig. 12 is a schematic flowchart of another control method for a power converter according to an embodiment of the present invention, and as shown in fig. 12, the method includes the following specific steps:

s610, the upper computer obtains the target output power and the target output voltage input by the user.

S620, the upper computer determines the number of independent DC/DC conversion modules to be started according to the target output power and the rated power of the independent DC/DC conversion modules; s630 and S660 are performed simultaneously.

And S630, each slave module receives the target output voltage of the power converter configured by the upper computer, the number of independent DC/DC conversion modules needing to be started and the current limiting value.

And S640, each slave module acquires the output current value of the slave module and the inductance current value of the slave module.

And S650, each slave module adjusts the duty ratio of a driving signal of at least one switching tube in the slave module according to the target output voltage, the number of independent DC/DC conversion modules needing to be started, the current limiting value, the output current value of the slave module and the inductance current value of the slave module, so that the output current of the slave module is equal to the current limiting value.

And S660, receiving a target output voltage and a current amplitude limiting value of a power converter configured by the upper computer by the main module.

And S670, the main module acquires the output voltage value of the main module and the inductance current value of the main module.

And S680, the main module adjusts the duty ratio of a driving signal of at least one switching tube in the main module according to the target output voltage, the current limiting value, the output voltage value of the main module and the inductance current value of the main module, so that the output voltage of the main module is equal to the target output voltage.

It should be noted that, in this embodiment, although steps S630 to S650 and steps S660 to S680 are described in a sequential order, steps S630 to S650 and steps S660 to S680 may be performed in a power converter in a near or almost simultaneous manner, and there is no typical sequential order.

On the basis of the above embodiment, optionally, the current limiting values corresponding to each independent DC/DC conversion module are the same; when the number of the independent DC/DC conversion modules needing to be started is 1, the current amplitude limiting value is equal to the maximum current value allowed by the independent DC/DC conversion modules; when the number of independent DC/DC conversion modules to be started is greater than 1, the current limiting value is equal to the target output power/(target output voltage) × the number of independent DC/DC conversion modules to be started).

As an exemplary embodiment, the process of clipping the first current reference value by the total current output of the power converter 01, the current output of the slave module 110 and the first clipping unit 1142 is further described. For example, assuming that the on-load 30v,900w is needed, in order to prolong the service life of each independent DC/DC conversion module as much as possible, the outputs of three parallel independent DC/DC conversion modules need to be equalized, and for this reason, the total output current needs to be 900/30=30a, so that 3 parallel independent DC/DC conversion modules can be selected, and each independent DC/DC conversion module limits the current output 10A.

Fig. 13 is a schematic diagram of the total current output of a power converter according to an embodiment of the present invention, and fig. 14 is a schematic diagram of the current output of a master/slave module according to an embodiment of the present invention. The power converter 01 includes two slave modules 110 and one master module 120 connected in parallel, and the current limiting value of the power converter 01 is known to be 10A according to the total number of the slave modules 110 and the master module 120 and the total output current of the total power converter 01. In fig. 13, the total current output by the power converter 01 is 30A, and the total output current keeps a stable current output after 0.1 second, which is beneficial to the stable operation of the load side.

In fig. 14, curves 11 and 12 are output current curves of the slave module 110, and a curve 21 is an output current curve of the master module 120. The output current of the slave module 110 shown by the curve 11 and the curve 12 is adjusted to be a current amplitude limiting value output which tends to be stable within 6 seconds, that is, the curve 11 and the curve 12 are change curves of the first current amplitude limiting reference value obtained by performing amplitude limiting processing on the first current reference value by the first amplitude limiting unit 1142 when the first current reference value is greater than the current amplitude limiting value. The output current of the main module 120 shown by the curve 21 is adjusted to be finally equal to the current clipping value, that is, the curve 21 is a variation curve of the second clipping unit 1242 making the second current reference value equal to the second current clipping reference value when the second current reference value is smaller than the current clipping value.

Therefore, the power converter and the control method thereof provided by the embodiment of the invention can achieve stable total current output in a very short time when the multistage parallel independent DC/DC conversion modules operate, and each conversion module can output current in a uniform way, so that the service life of each conversion module can be fully prolonged.

The control method of the power converter provided in the embodiment of the present invention may be executed by the power converter provided in any embodiment of the present invention, and has the beneficial effects of the power converter provided in any embodiment of the present invention, and details thereof are not repeated herein.

Fig. 15 is a schematic structural diagram of a power conversion system according to an embodiment of the present invention, where the power conversion system includes: the power converter 01 is configured to execute the control method provided by any embodiment of the invention, so that the battery 200 provides energy for the load 300 through the power converter 01.

In addition, the power conversion system provided in the embodiment of the present invention includes the power converter 01 provided in any embodiment of the present invention, and therefore, the power conversion system has the beneficial effects of the power converter 01 provided in any embodiment of the present invention, and details thereof are omitted here.

The above-mentioned serial numbers of the embodiments of the present application are merely for description, and do not represent the advantages and disadvantages of the embodiments.

In the present application, the same or similar descriptions of terms, technical solutions and/or application scenarios will generally be described in detail only when they occur for the first time, and when they occur repeatedly later, they will not be repeated again for brevity, and in understanding the technical solutions and the like of the present application, reference may be made to the related detailed descriptions and the like before the same or similar descriptions of terms, technical solutions and/or application scenarios and the like which are not described in detail later.

In the present application, each embodiment is described with an emphasis on the description, and reference may be made to the description of other embodiments for parts that are not described or recited in any embodiment.

All possible combinations of the technical features in the embodiments are not described in the present application for the sake of brevity, but should be considered as the scope of the present application as long as there is no contradiction between the combinations of the technical features.

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 application may be embodied in the form of a software product, which is stored in a storage medium (e.g., ROM/RAM, magnetic disk, optical disk) and includes instructions for enabling a terminal device (e.g., an electric device or a network device) to execute the method of each embodiment of the present application.

The above description is only a preferred embodiment of the present application, and not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings of the present application, or which are directly or indirectly applied to other related technical fields, are included in the scope of the present application.

Claims

1. A power converter is characterized by comprising a plurality of independent DC/DC conversion modules connected in parallel, wherein the independent DC/DC conversion modules connected in parallel comprise at least one slave module; the slave module includes:

and the current-sharing control module is used for determining a first current reference value according to the output current of the slave module, the target output voltage and the number of the independent DC/DC conversion modules needing to be started, determining a first current amplitude limiting reference value according to the current amplitude limiting value and the first current reference value, and adjusting the duty ratio of a driving signal of at least one switching tube in the slave module according to the inductance current value of the slave module and the first current amplitude limiting reference value so as to enable the output current of the slave module to be equal to the current amplitude limiting value.

2. The power converter of claim 1, wherein the current sharing control module comprises:

3. The power converter according to claim 2, wherein the first voltage outer loop control unit is configured to perform PI adjustment on a difference between the output current value of the slave module and a ratio of the target output voltage and the number of the independent DC/DC conversion modules to be started, with the output current value of the slave module as a negative feedback quantity, and determine the first current reference value;

4. The power converter according to any of claims 1-3, wherein the plurality of parallel independent DC/DC conversion modules further comprises a master module connected in parallel with the at least one slave module; the main module includes:

5. The power converter of claim 4, wherein the regulation control module comprises:

6. The power converter according to claim 5, wherein the second voltage outer loop control unit is configured to perform PI adjustment on a difference between the output voltage value of the main module and the target output voltage by using the output voltage value of the main module as a negative feedback quantity to determine the second current reference value;

and the second current inner loop control unit is used for performing PI regulation on a difference value between the inductance current value of the main module and the second current amplitude limiting reference value by taking the inductance current value of the main module as a negative feedback quantity, and determining the duty ratio of a driving signal of at least one switching tube in the main module.

7. The power converter of claim 1,

the current limiting values corresponding to each independent DC/DC conversion module are the same;

8. The power converter according to claim 7, wherein the number of independent DC/DC conversion modules to be started is determined according to the target output power and the rated power of the independent DC/DC conversion modules.

9. A control method of a power converter is characterized in that the power converter comprises a plurality of independent DC/DC conversion modules which are connected in parallel, and the independent DC/DC conversion modules which are connected in parallel comprise at least one slave module; the control method comprises the following steps:

each slave module determines a first current reference value according to the output current of the slave module, the target output voltage and the number of the independent DC/DC conversion modules needing to be started, determines a first current limiting reference value according to the current limiting value and the first current reference value, and adjusts the duty ratio of a driving signal of at least one switching tube in the slave module according to the inductance current value of the slave module and the first current limiting reference value so as to enable the output current of the slave module to be equal to the current limiting value.

10. A power conversion system, comprising: a battery, a power converter and a load, the power converter being configured to perform the control method of claim 9 such that the battery provides energy to the load through the power converter.