WO2023103352A1

WO2023103352A1 - Direct-current power collection system of wave energy power generation device, and control method and system therefor

Info

Publication number: WO2023103352A1
Application number: PCT/CN2022/101828
Authority: WO
Inventors: 刘石; 王红星; 吴亦竹; 李铭钧; 段新辉; 梁崇淦; 刘志刚; 杨毅; 郭欣然; 郭敬梅; 魏焱; 廖鹏
Original assignee: 南方电网电力科技股份有限公司
Priority date: 2021-12-09
Filing date: 2022-06-28
Publication date: 2023-06-15
Also published as: CN114188933A; CN114188933B

Abstract

A direct-current power collection system of a wave energy power generation device, and a control method and system therefor. The direct-current power collection system comprises n sub-modules, and each sub-module comprises two half-bridge modules and one high-frequency inductor. Low-voltage sides of the sub-modules in the direct-current power collection system are dispersed and can be independently connected to a wave energy power generator unit, high-voltage sides of a plurality of sub-modules are connected in series and connected to a high-voltage direct-current network, such that high-voltage electric energy transfer is achieved, and the construction costs of converters and network structures thereof are effectively reduced. The present application further provides a control method and system for the direct-current power collection system to achieve series decoupling and independent control of sub-modules at high-voltage sides, bidirectional flow of power, and self-adaptive control of wave energy generator units. Therefore, the technical problems of poor stability and high costs in the prior art are solved.

Description

A DC current collection system of a wave energy generating device and its control method and system

This application claims the priority of the Chinese patent application submitted to the China Patent Office on December 09, 2021, with the application number 202111503579.X, and the title of the invention is "a DC current collection system for a wave energy power generation device and its control method and system" rights, the entire contents of which are incorporated in this application by reference.

technical field

The present application relates to the field of electric power technology, and in particular to a DC current collection system of a wave energy generating device and a control method and system thereof.

Background technique

Wave energy is a rich renewable marine resource with a series of characteristics such as large storage capacity, wide distribution space, and no pollution. Under the development background of "carbon peaking and carbon neutrality", the use of wave energy to generate electricity has broad applications prospect. The array floater wave energy power generation can absorb wave energy in different positions continuously and evenly by arranging multiple oscillating floats in an orderly array in a certain sea area, which better meets the requirements of large-scale and large-scale power generation. At present, it is an important direction for the research and development of large-scale wave energy generation devices.

At present, there are two ways of AC collection and DC collection for large-scale array buoy type wave energy generation devices. The AC collection method adopts at least two stages of transformation (AC/DC+DC/AC) to realize stable AC power series/parallel transmission. However, in the AC collection method, there are many control factors (amplitude, frequency, phase angle), many times of power conversion, the converter structure and control are difficult, and the construction cost is high, which seriously restricts the development of the AC collection method in the field of wave energy generation. . The DC collection methods mainly include the DC series form and the DC parallel form. The DC collection methods mainly include: DC series connection and DC parallel connection. in. The DC parallel connection is limited by the withstand voltage level and power level of semiconductor devices. The DC parallel connection usually requires multiple DC converters to convert low-voltage/medium-voltage DC to high-voltage DC and realize high-voltage voltage transmission. This will greatly increase the realization cost of the DC collection mode of the wave energy generation device, which hinders the development of wave energy generation; in the DC series mode, each converter is essentially a current source on the high-voltage side, and there is a serious coupling problem between the ports, which makes Under the disturbance of wave characteristics, each port presents the characteristics of unbalanced voltage distribution, which increases the complexity of control and is not conducive to the safe and stable operation of the DC series system.

Contents of the invention

The present application provides a DC current collection system of a wave energy generating device and its control method and system, which are used to solve the technical problems of poor stability and high cost in the prior art.

In view of this, the first aspect of the present application provides a DC power collection system of a wave energy generating device, the system comprising:

n sub-modules, the sub-modules include: a diode, a low-voltage side half-bridge module composed of an input-side capacitor, a first switch tube, and a second switch tube, a high-frequency inductor, an output-side capacitor, a third switch tube, and a fourth switch tube. A high-voltage side half-bridge module composed of switching tubes;

The switching tube in the low-voltage side half-bridge module is connected in antiparallel to the diode, and the diode is connected to the output interface of the wave energy generator set;

The low-voltage side half-bridge module is connected to the high-voltage side half-bridge module through the high-frequency inductor;

The high-voltage side half-bridge modules in two adjacent sub-modules are connected in series as high-voltage side ports, and connected to the high-voltage direct current grid.

Optionally, the low-voltage-side half-bridge module composed of an input-side capacitor, a first switch tube, and a second switch tube specifically includes:

After the first switch tube and the second switch tube are connected in series, they are connected in parallel with the input side capacitor;

The first switch tube is a high-voltage side switch tube, and the second switch tube is a low-voltage side switch tube.

Optionally, the high-voltage-side half-bridge module composed of an output-side capacitor, a third switch tube, and a fourth switch tube specifically includes:

After the third switch tube and the fourth switch tube are connected in series, they are connected in parallel with the output side capacitor;

The third switching tube is a high-voltage side switching tube, and the fourth switching tube is a low-voltage side switching tube.

Optionally, the low-voltage side half-bridge module is connected to the high-voltage side half-bridge module through the high-frequency inductor, specifically including:

The two ends of the second switching tube in the low-voltage side half-bridge module are led out to form a low-voltage side high-frequency port, which is connected in series with the high-frequency inductor;

Both ends of the fourth switching tube in the high-voltage side half-bridge module are led out to form a high-voltage side high-frequency port and connected to a high-frequency inductor.

The second aspect of the present application provides a control method of a DC power collection system, which is applied to the DC power collection system of the wave energy generation device described in the first aspect, and the method includes:

Select the control strategy according to the type of wave energy generating set and rectifier connected to the sub-module;

When the type of sub-module connected is a wave energy generator set without control rectification, the first modulation wave signal of the sub-module is generated through the control frame composed of the speed control loop, the output voltage control loop and the inductance current loop, and is used in the sub-module The switch tube is controlled;

When the sub-module is connected to a PWM rectified wave energy generator set, the second modulation wave signal of the sub-module is generated through the output voltage control loop and the inductor current loop to control the switching tube in the sub-module.

Optionally, the control frame composed of the speed control loop, the output voltage control loop and the inductance current loop generates the first modulation wave signal of the sub-module to control the switching tube in the sub-module, specifically including:

The difference between the speed reference value and the actual speed of the generator set is output by the PI controller, and the difference between the voltage reference value and the actual output voltage of the generator set is passed through the output value of the PI controller to jointly generate the first inductor current. The reference value, after comparing the first reference value with the actual inductor current value, the PI controller generates the first modulation wave signal of the sub-module to control the switch tube in the sub-module.

Optionally, generating the second modulated wave signal of the sub-module through the output voltage control loop and the inductor current loop to control the switching tube in the sub-module specifically includes:

The difference between the output voltage reference value of the generator set and the actual output voltage is generated by the PI controller to generate the reference value of the inductor current, and after comparing the reference value of the inductor current with the actual inductor current value, the PI controller generates the first sub-module The second modulation wave signal is used to control the switch tube in the sub-module.

The third aspect of the present application provides a control system for a DC power collection system, the system comprising:

The analysis module is used to select a control strategy according to the type of the wave energy generating set and the rectifier connected to the sub-module;

The first control module is used to generate the first modulation of the sub-module through the control frame composed of the speed control loop, the output voltage control loop and the inductor current loop when the sub-module is connected to a wave energy generator set without control rectification Wave signal to control the switching tube in the sub-module;

The second control module is used to generate the second modulated wave signal of the sub-module through the output voltage control loop and the inductance current loop when the sub-module is connected to a PWM rectified wave energy generator set, and to control the switching tube in the sub-module Take control.

Optionally, the first control module is specifically used for:

When the type connected to the sub-module is a non-controlled rectification wave energy generator set, the difference between the reference speed value and the actual speed of the generator set will be compared with the voltage reference value and actual output voltage of the generator set through the output value of the PI controller. The difference between the output values of the PI controller together generates the first reference value of the inductor current. After comparing the first reference value with the actual inductor current value, the PI controller generates the first modulation wave signal of the sub-module. The switching tube in the sub-module is controlled.

Optionally, the second control module is specifically used for:

When the sub-module is connected to a PWM rectified wave energy generator set, the difference between the output voltage reference value of the generator set and the actual output voltage is generated by the PI controller to generate a reference value of the inductor current, and the reference value of the inductor current and After the actual inductor current values are compared, the PI controller generates a second modulation wave signal of the sub-module to control the switch tube in the sub-module.

As can be seen from the above technical solutions, the present application has the following advantages:

The present application provides a DC power collection system of a wave energy generating device and its control method and system. The DC power collection system includes n sub-modules, and the sub-modules include two half-bridge modules and a high-frequency inductor. The low-voltage side of the sub-modules in the DC power collection system is dispersed and can be independently connected to the wave energy generator set; multiple sub-modules on the high-voltage side are connected in series and connected to the high-voltage DC network to realize high-voltage power transmission and effectively reduce the construction of converters and their network structures cost. This application further proposes a control method for a DC power collection system, which realizes series decoupling of sub-modules on the high voltage side, independent control, bidirectional flow of power and adaptive control of wave energy generators.

Compared with the prior art, the present application is beneficial in that:

(1) The DC current collection system adapts to different types of wave energy generators and their rectification forms, and realizes the flexible independent control and optimal power output application of multiple wave energy generators.

(2) The low-voltage side of the sub-modules in the DC power collection system is dispersed, and the high-voltage side is connected in series, which reduces the number of power electronic power conversion modules and effectively reduces the construction cost of the converter and its network structure.

(3) The DC collector sub-module is independent, the control structure is simple, and the stability is strong, which can effectively suppress the high-voltage DC voltage oscillation caused by the voltage and power fluctuations of the wave energy generating set.

Description of drawings

Fig. 1 is a schematic diagram of the topology of a DC power collection system of a wave energy generating device provided in an embodiment of the present application;

FIG. 2 is a schematic flowchart of an embodiment of a method for controlling a DC power collection system provided in an embodiment of the present application;

FIG. 3 is a schematic structural diagram of an embodiment of a control system for a DC power collection system provided in an embodiment of the present application;

Fig. 4 is a schematic diagram of the sub-module structure of the DC power collection system;

Fig. 5 is a schematic diagram of a submodule modulation strategy;

Fig. 6a is a schematic diagram of the step-down mode of the sub-module;

Figure 6b is a schematic diagram of the boost mode of the sub-module;

7 is a schematic diagram of a control strategy of a DC power collection system;

Fig. 8 is a schematic diagram of a control strategy for an uncontrolled rectifier interface;

Fig. 9 is a schematic diagram of a control strategy for a PWM rectifier interface;

Fig. 10 is a voltage schematic diagram of the DC power collection system and its sub-modules under balanced wave power;

Figure 11 is a voltage schematic diagram of the DC power collection system and its sub-modules under unbalanced wave power;

Fig. 12a is a voltage schematic diagram of the DC power collection system and its sub-modules under time-varying wave power imbalance;

Fig. 12b is a schematic diagram of time-varying wave power unbalanced input mechanical torque.

Detailed ways

In order to enable those skilled in the art to better understand the solution of the application, the technical solution in the embodiment of the application will be clearly and completely described below in conjunction with the drawings in the embodiment of the application. Obviously, the described embodiment is only It is a part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

Please refer to Fig. 1, a DC power collection system of a wave energy generating device provided in the embodiment of the present application, including:

n sub-modules (n is a positive integer), the sub-modules include: a diode, a high-frequency inductor, a low-voltage-side half-bridge module formed by connecting the first switch tube and the second switch tube in series, and then connected in parallel with the input-side capacitor; the third After the switching tube and the fourth switching tube are connected in series, they are connected in parallel with the output side capacitor to form a high-voltage side half-bridge module; wherein, the first switching tube is a high-voltage side switching tube, the second switching tube is a low-voltage side switching tube, and the third switching tube is a high-voltage side switch tube, and the fourth switch tube is a low-voltage side switch tube. The switching tube in the half-bridge module on the low-voltage side is connected in antiparallel to the diode, and the diode is connected to the output interface of the wave energy generator set; The inductors are connected in series; the high-voltage side half-bridge modules in two adjacent sub-modules are connected in series as high-voltage side ports, and then connected to the high-voltage DC power grid.

It should be noted that in actual engineering, a permanent magnet synchronous motor (Permanent Magnet Synchronous Motor, PMSM) can be used as a wave energy generator set, and further DC power conversion is performed through an uncontrolled rectifier or a PWM rectifier.

The sub-modules of the DC power collection system proposed in this embodiment adopt a four-switch buck-boost DC converter, where V _i , i=1, 2, 3 . . . are the low-voltage DC side voltages of each sub-module. V _si is the high-voltage side voltage of the sub-module.

The high-voltage sides of the sub-modules are connected in series, and the sum of the voltages is the high-voltage DC bus voltage V _s . C _i , L _i , and C _si are the input capacitance, input inductance, and output capacitance of the i-th sub-module, respectively.

The i-th sub-module also includes four switching tubes and diodes, wherein the switching tubes and diodes are connected in antiparallel, the first switching tube and the second switching tube are connected in series, and then connected in parallel with the input side capacitor to form a low-voltage side half-bridge module. The switching tube is a high-voltage side switching tube, and the second switching tube is a low-voltage side switching tube. The voltage at both ends of the capacitor on the input side is V _i , and the two ends of the second switching tube are drawn out to form a high-frequency port on the low-voltage side. After being connected in series with a high-frequency inductor , and connect to the high-voltage side half-bridge module.

In the high-voltage side half-bridge, the third switching tube and the fourth switching tube are connected in series, and then connected in parallel with the output side capacitor. The third switching tube is the high-voltage side switching tube, and the fourth switching tube is the low-voltage side switching tube. The voltage is V _si , and the two ends of the fourth switching tube are led out to form a high-voltage side high-frequency port, which is connected to the high-frequency inductor.

The electrical output interfaces of each wave energy generating set are independent of each other, and are connected to sub-modules in a decentralized manner. The high-voltage side ports of the sub-modules are connected in series and connected to the high-voltage DC power grid.

Please refer to Figure 1 and Figure 4. Figure 4 is a schematic diagram of the sub-modules of the DC power collection system, which can realize the up-down conversion of DC voltage, satisfy the bidirectional flow of electric energy, and adapt to different rectifier interfaces of wave energy generation devices, and further adjust the wave The operating mode of the generator set can be optimized to optimize the handling characteristics of the generator set.

In a DC collector system, each sub-module operates independently. The modulation strategy of the sub-module is shown in Figure 5, where V _c1 and V _c2 are carrier waves, V _r is the modulating wave, and V _s1 and V _s3 are the driving signals of S _i1 and S _i3 . The switch driving signals of the same bridge arm are mutually conducted. Therefore, when V _r is completely lower than V _c2 , the sub-module works in buck mode, as shown in Figure 6a. When V _r is completely higher than V _c1 , the sub-module works in boost mode, as shown in Figure 6b.

Combining Figure 5 and Figure 6a, keep S _i3 off and S _i4 on. S _i1 and S _i2 make the sub-module a bidirectional buck converter. The output voltage is expressed as:

V _si =D*V _i (1)

Combining Figure 5 and Figure 6b, keep S _i2 off and S _i1 on. S _i3 and S _i4 can make the sub-module a bidirectional boost converter. The output voltage is expressed as:

V _si =V _i /(1-D) (2)

For DC collectors, the high voltage DC side voltage is:

Vs＝ΣV _si (3)

Therefore, the operation mode of the sub-module can be adaptively changed according to the voltage V _i and V _r , while ensuring the voltage stability of the high-voltage side port and the efficient operation of the wave energy generator set.

In the application of wave power generation devices, uncontrolled rectifiers and PWM rectifiers are used for power conversion, and are used as power input power sources for DC collectors. In the PWM rectifier, the maximum power point (MPP) of the wave energy can be tracked and the DC bus voltage can be controlled. Therefore, the function of the sub-module of the DC current collection system is to ensure the stable operation of the series voltage V _si . In an uncontrolled rectifier, the PMSM speed, MPP and DC bus voltage are not controlled. Therefore, the series voltage V _si stabilization and MPP tracking can be realized through sub-modules.

The above is an embodiment of a direct current collection system of a wave energy generating device provided in the embodiment of the present application, and the following is an embodiment of a control method of the direct current collection system provided in the embodiment of the present application.

Aiming at various rectification methods in the application of wave power generation, this application also proposes an adaptive control framework for the DC current collection system, as shown in FIG. 7 . The control method of the present application is realized through three control loops, specifically: 1) PMSM speed control loop, 2) series output voltage control loop, and 3) current control loop.

The PMSM speed control loop is suitable for wave energy generators with uncontrolled rectifier interfaces. The series output voltage and current control loops co-exist in the wave energy generator set with the PWM rectifier interface and the uncontrolled rectifier interface to achieve fast current response and stable high-voltage DC voltage on the series side.

Please refer to Fig. 2, a control method of a DC power collection system provided in the embodiment of the present application, including:

Step 101, select a control strategy according to the type of wave energy generating set and rectifier connected to the sub-module;

It can be understood that the type and signal interface of the wave energy generating set connected to the low-voltage side port of the sub-module connected to the DC power collection system and its rectifier are judged.

Step 102. When the type of sub-module connected is a wave energy generator set without control rectification, the first modulation wave signal of the sub-module is generated through the control frame composed of the speed control loop, the output voltage control loop and the inductance current loop. The switching tube in the sub-module is controlled;

It should be noted that the sub-module is connected to a wave energy generator set without rectification control, and the speed of the generator set, the output voltage of the sub-module and the inductor current need to be sampled as the judgment basis.

When the sub-module is connected to the wave energy generator set without control rectification, the sub-module control strategy adopts control strategy 1, as shown in Figure 8, including: speed control loop, output voltage control loop and inductor current loop. Among them, the difference generated by the comparison between the speed reference value and the actual speed passes through the output value of the PI controller, and the difference generated by comparing the output voltage reference value with the actual output voltage passes through the output value of the PI controller to jointly generate the reference value of the inductor current. . After the reference value of the inductance current is compared with the actual inductance current value, the PI controller generates the modulation wave signal of the sub-module to control the switching tube to realize the optimal power control of the wave energy generator set, the stability of the output voltage of the sub-module and the DC integration. Fast dynamic response of electrical system.

Step 103: When the sub-module is connected to a PWM rectified wave energy generator set, generate a second modulated wave signal of the sub-module through the output voltage control loop and the inductor current loop to control the switch tube in the sub-module.

It should be noted that when the sub-module is connected to the PWM rectified wave energy generator set, the control strategy of the sub-module adopts the control strategy 2, as shown in Figure 9, including: the output voltage control loop and the inductor current loop. Among them, the difference between the output voltage reference value and the actual output voltage is generated by the PI controller to generate the reference value of the inductor current. After the reference value of the inductor current is compared with the actual inductor current value, the PI controller generates the modulation wave signal of the sub-module to control the switching tube, so as to realize the stability of the output voltage of the sub-module and the fast dynamic response of the DC collector system.

The above-mentioned DC power collection system takes two sub-modules as an example. Among them, the sub-module 1 is connected to the non-controlled rectification wave energy generator set, and the control strategy 1 is adopted, and the sub-module 2 is connected to the PWM rectifier generator set, and the control strategy 2 is adopted.

Referring to Figures 10, 11, 12a, and 12b, the output voltages of

sub-modules

1 and 2 are stable at 375V, and the high voltage side voltage Vs is maintained at 750V. Each sub-module can be controlled independently, and the voltage of the sub-modules is balanced, which effectively avoids the problem of voltage imbalance in the series structure.

In Fig. 10, when the input torque is rated, V _s1 , V _s2 and V _s remain stable. At 2s, the load changes from 50% load to full load, and the voltage on the high voltage side can return to normal level after a short-term slight fluctuation, and maintain stable operation.

In Fig. 11, when the input torque 1 is 1.0pu and the input torque 2 is 1.25pu, V _s1 , V _s2 and V _s remain stable. At the moment of 2s, the load changes from 50% to full load, and the voltage on the high voltage side can return to the normal level after a brief slight fluctuation, and maintain stable operation.

In Figures 12a, 12b, the input torque 1 increases at a rate of 1 p.u./s, and the input torque 2 increases at a rate of 0.5 pu/s at 2s. The load changes from 50% to full load, but the voltage remains at the normal level, V _s1 and V _s2 are 375V, V _s is 750V, and the DC collector maintains stable operation.

Therefore, the DC current collection system of the large-scale array type wave energy generation device and the control method thereof of the present application can maintain the balance and stability of the voltage of the sub-modules, and ensure the stability of the high-voltage DC voltage for wave energy applications. Moreover, the wave energy generator set can be used as the voltage source of the DC collector, so that the sub-modules of the DC collector can operate independently of each other, effectively avoiding the problem of voltage imbalance in the series structure.

The above is an embodiment of a control method for a DC power collection system provided in the embodiments of the present application, and the following is an embodiment of a control system for a DC power collection system provided in the embodiments of the present application.

Please refer to Fig. 3, a control system of a DC power collection system is provided in the embodiment of the present application, including:

The analysis module 201 is used to select a control strategy according to the type of the wave energy generating set and the rectifier connected to the sub-module;

The first control module 202 is used to generate the first control module of the sub-module through the control framework composed of the speed control loop, the output voltage control loop and the inductor current loop when the type connected to the sub-module is an uncontrolled rectification wave energy generator set. Modulate the wave signal to control the switching tube in the sub-module;

The second control module 203 is used to generate the second modulated wave signal of the sub-module through the output voltage control loop and the inductance current loop when the type of the sub-module connected is a PWM rectified wave energy generator set, and to switch in the sub-module tube control.

Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working process of the system and units described above can refer to the corresponding process in the foregoing method embodiments, and details are not repeated here.

The terms "first", "second", "third", "fourth" and the like in the description of the present application and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence . It is to be understood that the data so used are interchangeable under appropriate circumstances such that the embodiments of the application described herein, for example, can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a sequence of steps or elements is not necessarily limited to the expressly listed instead, may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

It should be understood that in this application, "at least one (item)" means one or more, and "multiple" means two or more. "And/or" is used to describe the association relationship of associated objects, indicating that there can be three types of relationships, for example, "A and/or B" can mean: only A exists, only B exists, and A and B exist at the same time , where A and B can be singular or plural. The character "/" generally indicates that the contextual objects are an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one item (piece) of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c ", where a, b, c can be single or multiple.

In the several embodiments provided in this application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or May be integrated into another system, or some features may be ignored, or not implemented. In another point, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or units may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, each unit may exist separately physically, or two or more units may be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

If the integrated unit is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or part of the contribution to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium , including several instructions to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage media include: U disk, mobile hard disk, read-only memory (English full name: Read-Only Memory, English abbreviation: ROM), random access memory (English full name: Random Access Memory, English abbreviation: RAM), magnetic Various media that can store program codes such as discs or optical discs.

As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still understand the foregoing The technical solutions described in each embodiment are modified, or some of the technical features are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the application.

Claims

A DC power collection system of a wave energy generating device, characterized in that it includes: n sub-modules, the sub-modules include: a diode, a low-voltage side half-bridge composed of an input-side capacitor, a first switching tube, and a second switching tube Module, high-frequency inductor, high-voltage-side half-bridge module composed of output-side capacitor, third switch tube, and fourth switch tube;

The switching tube in the low-voltage side half-bridge module is connected in antiparallel to the diode, and the diode is connected to the output interface of the wave energy generator set;

The low-voltage side half-bridge module is connected to the high-voltage side half-bridge module through the high-frequency inductor;

The high-voltage side half-bridge modules in two adjacent sub-modules are connected in series as high-voltage side ports, and connected to the high-voltage direct current grid.
The DC power collection system of a wave energy generating device according to claim 1, wherein the low-voltage-side half-bridge module composed of an input-side capacitor, a first switching tube, and a second switching tube specifically includes:

After the first switch tube and the second switch tube are connected in series, they are connected in parallel with the input side capacitor;

The first switch tube is a high-voltage side switch tube, and the second switch tube is a low-voltage side switch tube.
The DC power collection system of a wave energy generating device according to claim 2, wherein the high-voltage-side half-bridge module composed of an output-side capacitor, a third switching tube, and a fourth switching tube specifically includes:

After the third switch tube and the fourth switch tube are connected in series, they are connected in parallel with the output side capacitor;

The third switching tube is a high-voltage side switching tube, and the fourth switching tube is a low-voltage side switching tube.
The DC power collection system of a wave energy generating device according to claim 3, wherein the low-voltage side half-bridge module is connected to the high-voltage side half-bridge module through the high-frequency inductor, specifically comprising:

The two ends of the second switching tube in the low-voltage side half-bridge module are led out to form a low-voltage side high-frequency port, which is connected in series with the high-frequency inductor;

Both ends of the fourth switching tube in the high-voltage side half-bridge module are led out to form a high-voltage side high-frequency port and connected to a high-frequency inductor.
A control method for a DC power collection system, characterized in that it is applied to the DC power collection system of the wave energy generating device described in any one of claims 1-4, the method comprising:

Select the control strategy according to the type of wave energy generating set and rectifier connected to the sub-module;

When the type of sub-module connected is a wave energy generator set without control rectification, the first modulation wave signal of the sub-module is generated through the control frame composed of the speed control loop, the output voltage control loop and the inductance current loop, and is used in the sub-module The switch tube is controlled;

When the sub-module is connected to a PWM rectified wave energy generator set, the second modulation wave signal of the sub-module is generated through the output voltage control loop and the inductor current loop to control the switching tube in the sub-module.
The control method of the DC power collection system according to claim 5, wherein the control frame composed of the speed control loop, the output voltage control loop and the inductance current loop generates the first modulated wave signal of the sub-module, for The switching tubes in the sub-modules are controlled, including:

The difference between the speed reference value and the actual speed of the generator set is output by the PI controller, and the difference between the voltage reference value and the actual output voltage of the generator set is passed through the output value of the PI controller to jointly generate the first inductor current. The reference value, after comparing the first reference value with the actual inductor current value, the PI controller generates the first modulation wave signal of the sub-module to control the switch tube in the sub-module.
The control method of the DC power collection system according to claim 5, wherein the second modulation wave signal of the sub-module is generated by the output voltage control loop and the inductance current loop to control the switching tube in the sub-module, Specifically include:

The difference between the output voltage reference value of the generator set and the actual output voltage is generated by the PI controller to generate the reference value of the inductor current, and after comparing the reference value of the inductor current with the actual inductor current value, the PI controller generates the first sub-module The second modulation wave signal is used to control the switch tube in the sub-module.
A control system for a direct current collection system, characterized in that it includes:

The analysis module is used to select a control strategy according to the type of the wave energy generating set and the rectifier connected to the sub-module;

The first control module is used to generate the first modulation of the sub-module through the control frame composed of the speed control loop, the output voltage control loop and the inductor current loop when the sub-module is connected to a wave energy generator set without control rectification Wave signal to control the switching tube in the sub-module;

The second control module is used to generate the second modulated wave signal of the sub-module through the output voltage control loop and the inductance current loop when the sub-module is connected to a PWM rectified wave energy generator set, and to control the switching tube in the sub-module Take control.
The control system of the DC power collection system according to claim 8, wherein the first control module is specifically used for:

When the type connected to the sub-module is a non-controlled rectification wave energy generator set, the difference between the reference speed value and the actual speed of the generator set will be compared with the voltage reference value and actual output voltage of the generator set through the output value of the PI controller. The difference between the output values of the PI controller together generates the first reference value of the inductor current. After comparing the first reference value with the actual inductor current value, the PI controller generates the first modulation wave signal of the sub-module. The switching tube in the sub-module is controlled.
The control system of the DC power collection system according to claim 8, wherein the second control module is specifically used for:

When the sub-module is connected to a PWM rectified wave energy generator set, the difference between the output voltage reference value of the generator set and the actual output voltage is generated by the PI controller to generate a reference value of the inductor current, and the reference value of the inductor current and After the actual inductor current values are compared, the PI controller generates a second modulation wave signal of the sub-module to control the switch tube in the sub-module.