CN117574020A - Valve loss calculation method and system of DRU converter - Google Patents
Valve loss calculation method and system of DRU converter Download PDFInfo
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Abstract
The invention discloses a valve loss calculation method and a system of a DRU converter, which relate to the technical field of converter valve loss, and when a valve side topological graph of the DRU converter to be analyzed is received, working condition parameters corresponding to the DRU converter to be analyzed are obtained according to a preset period, corresponding diode quantity values are determined according to the valve side topological graph and the working condition parameters, the working condition parameters are input into a preset loss analysis model, corresponding loss data are generated, and the valve loss values corresponding to the DRU converter to be analyzed are determined according to the diode quantity values, the period and the loss data. The method and the device solve the technical problems that the valve loss calculation of the DRU mainly builds a corresponding simulation model, the valve loss of the DRU is calculated through the simulation model, the accuracy of a calculation result depends on the accuracy of the simulation model and is difficult to apply to a DRU-MMC system with higher level number, and the operation reliability of the DRU-MMC system is reduced.
Description
Technical Field
The invention relates to the technical field of converter valve loss, in particular to a valve loss calculation method and a system of a DRU converter.
Background
With the development of power electronics technology, diode Rectification Units (DRUs) are receiving increasing attention from the academia and industry. Compared with other low-cost converter topologies, the DRU has smaller power consumption, lower cost and higher reliability, and has great development potential in offshore wind power grid-connected scenes. It is estimated that the investment cost when DRUs are used for offshore platforms will be reduced by 65% compared to MMC-HVDC solutions, which is widely used for remote offshore wind power. The valve loss of the DRU plays a crucial role in the long-term operation cost and the operation performance of the system, and is directly related to the safe, stable and economic operation of the system.
At present, the valve loss calculation of the DRU mainly builds a corresponding simulation model, and the valve loss of the DRU is calculated through the simulation model, but the calculation result precision depends on the simulation model precision, the calculation time is long, the method is difficult to be applied to a DRU-MMC system with high level number, and the operation reliability of the DRU-MMC system is reduced.
Disclosure of Invention
The invention provides a valve loss calculation method and a system of a DRU converter, which solve the technical problems that the valve loss calculation of the DRU is mainly implemented by a corresponding simulation model, the valve loss of the DRU is calculated through the simulation model, the accuracy of a calculation result depends on the accuracy of the simulation model, the calculation time is long, the calculation time is difficult to be applied to a DRU-MMC system with higher level number, and the operation reliability of the DRU-MMC system is reduced.
The valve loss calculation method of the DRU converter provided by the first aspect of the invention is applied to the DRU converter in a flexible low-frequency system, and comprises the following steps:
when a valve side topological graph of a DRU converter to be analyzed is received, working condition parameters corresponding to the DRU converter to be analyzed are obtained according to a preset period;
determining corresponding diode quantity values according to the valve side topological graph and the working condition parameters;
inputting the working condition parameters into a preset loss analysis model to generate corresponding loss data;
and determining a valve loss value corresponding to the DRU converter to be analyzed according to the diode quantity value, the period and the loss data.
Optionally, the working condition parameters include a bridge arm maximum circulation current, a valve side no-load line voltage, a reverse breakdown voltage and an allowable circulation current, and the step of determining the corresponding diode number value according to the valve side topological graph and the working condition parameters includes:
performing ratio processing on the valve side no-load line voltage and the reverse breakdown voltage to generate a first ratio;
performing ratio processing on the maximum circulating current of the bridge arm and the allowable circulating current to generate a second ratio;
extracting the diode series number and the diode parallel number of the valve side topological graph, wherein the diode series number is larger than or equal to the first ratio, and the diode parallel number is larger than or equal to the second ratio;
and multiplying the serial number of the diodes and the parallel number of the diodes to generate a diode number value.
Optionally, the working condition data further includes on-state voltage, on-state resistance, on-device current, forward cut-off voltage, forward cut-off resistance and switching characteristic data, the loss analysis model includes an on-state analysis model, a cut-off analysis model and a switching loss analysis model, and the step of inputting the working condition parameters into a preset loss analysis model to generate corresponding loss data includes:
inputting the on-state voltage, the on-state resistance and the on-state device current into the on-state analysis model to generate a corresponding diode on-state loss value;
inputting the forward cut-off voltage and the forward cut-off resistance into the cut-off analysis model to generate a corresponding diode cut-off loss value;
inputting the switching characteristic data and the current of the conducting device into the switching loss analysis model to generate a corresponding switching loss value;
the diode on-state loss value, the diode off-state loss value and the switching loss value are adopted as loss data.
Optionally, the on-state analysis model is specifically:
wherein P is Dcon I is the on-state loss value of the diode f To conduct the device current, V f0 Is of on-state voltage, r f Is an on-state resistance.
Optionally, the cut-off analysis model is specifically:
wherein P is Doff For the cut-off loss value of the diode, V D For positive cut-off voltage, R Doff Is a forward cut-off resistance.
Optionally, the switching loss analysis model is specifically:
wherein E is rec The switching loss value is a first switching characteristic coefficient, b is a second switching characteristic coefficient, c is a third switching characteristic coefficient, and k is a temperature correction coefficient.
Optionally, the step of determining a threshold loss value corresponding to the DRU converter to be analyzed according to the diode quantity value, the period and the loss data includes:
multiplying the diode quantity value with a preset first working condition threshold value to generate a first multiplied value;
multiplying the first multiplication value with a preset second working condition threshold value to generate a second multiplication value;
multiplying the first multiplication value with the diode on-state loss value to generate a device on-state loss value;
multiplying the first multiplication value and the diode cut-off loss value to generate a device cut-off loss value;
multiplying the second multiplication value with the switching loss value to generate a third multiplication value;
performing ratio processing on the third multiplication value and the period to generate a switching loss value;
and adding the switching loss value, the device on-state loss value and the device off-state loss value to generate a valve loss value corresponding to the DRU converter to be analyzed.
The valve loss calculation system of the DRU converter provided in the second aspect of the invention is applied to the DRU converter in the flexible low-frequency system, and comprises:
the acquisition module is used for acquiring working condition parameters corresponding to the DRU converter to be analyzed according to a preset period when receiving the valve side topological graph of the DRU converter to be analyzed;
the extraction module is used for determining corresponding diode quantity values according to the valve side topological graph and the working condition parameters;
the first analysis module is used for inputting the working condition parameters into a preset loss analysis model to generate corresponding loss data;
and the second analysis module is used for determining a valve loss value corresponding to the DRU converter to be analyzed according to the diode quantity value, the period and the loss data.
Optionally, the working condition parameters include bridge arm maximum circulation current, valve side no-load line voltage, reverse breakdown voltage and allowable circulation current, and the extracting module includes:
the first ratio submodule is used for carrying out ratio processing on the valve side no-load line voltage and the reverse breakdown voltage to generate a first ratio;
the second ratio submodule is used for performing ratio processing on the maximum circulating current of the bridge arm and the allowable circulating current to generate a second ratio;
the extraction submodule is used for extracting the diode serial number and the diode parallel number of the valve side topological graph, wherein the diode serial number is larger than or equal to the first ratio, and the diode parallel number is larger than or equal to the second ratio;
and the quantity analysis submodule is used for multiplying the serial number of the diodes and the parallel number of the diodes to generate a diode quantity value.
Optionally, the working condition data further includes on-state voltage, on-state resistance, on-device current, forward cut-off voltage, forward cut-off resistance, and switching characteristic data, the loss analysis model includes an on-state analysis model, a cut-off analysis model, and a switching loss analysis model, and the first analysis module includes:
the first analysis submodule is used for inputting the on-state voltage, the on-state resistance and the on-state device current into the on-state analysis model to generate a corresponding diode on-state loss value;
the second analysis submodule is used for inputting the forward cut-off voltage and the forward cut-off resistance into the cut-off analysis model to generate a corresponding diode cut-off loss value;
the third analysis submodule is used for inputting the switching characteristic data and the current of the conducting device into the switching loss analysis model to generate a corresponding switching loss value;
the diode on-state loss value, the diode off-state loss value and the switching loss value are adopted as loss data.
From the above technical scheme, the invention has the following advantages:
when a valve side topological graph of the DRU converter to be analyzed is received, working condition parameters corresponding to the DRU converter to be analyzed are obtained according to a preset period, corresponding diode quantity values are determined according to the valve side topological graph and the working condition parameters, the working condition parameters are input into a preset loss analysis model, corresponding loss data are generated, and valve loss values corresponding to the DRU converter to be analyzed are determined according to the diode quantity values, the period and the loss data. The method and the device solve the technical problems that the valve loss calculation of the DRU mainly builds a corresponding simulation model, the valve loss of the DRU is calculated through the simulation model, the calculation result precision depends on the simulation model precision, the calculation time is long, the method and the device are difficult to apply to a DRU-MMC system with high level number, and the operation reliability of the DRU-MMC system is reduced. According to the invention, through analyzing the valve loss distribution characteristics of the DRU-MMC system topological graph, the accurate calculation is performed by utilizing the diode quantity value, the loss data and the period, and the valve loss value corresponding to the DRU converter to be analyzed is obtained.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings can be obtained from these drawings without inventive faculty for a person skilled in the art.
Fig. 1 is a flowchart of a valve loss calculation method of a DRU converter according to an embodiment of the present invention;
fig. 2 is a step flowchart of a valve loss calculating method of a DRU converter according to a second embodiment of the present invention;
fig. 3 is a schematic diagram of DRU side topology according to a second embodiment of the present invention;
FIG. 4 is a schematic diagram of an ideal parallel model of a diode module according to a second embodiment of the present invention;
fig. 5 is a schematic diagram of a topology structure of a low-frequency grid-structured fan offshore wind power ac transmission system according to a second embodiment of the present invention;
fig. 6 is a schematic diagram of simulation results of ac voltage effective values at ac side of a DRU inverter according to a second embodiment of the present invention;
fig. 7 is a schematic diagram of a dc voltage simulation result of a DRU inverter according to a second embodiment of the present invention;
fig. 8 is a block diagram of a valve loss calculation system of a DRU converter according to a third embodiment of the present invention.
Detailed Description
The embodiment of the invention provides a valve loss calculation method and a system of a DRU converter, which are used for solving the technical problems that the valve loss calculation of the DRU is mainly constructed into a corresponding simulation model, the valve loss of the DRU is calculated through the simulation model, the calculation result precision depends on the simulation model precision, the calculation time is long, the calculation time is difficult to be applied to a DRU-MMC system with higher level number, and the operation reliability of the DRU-MMC system is reduced.
In order to make the objects, features and advantages of the present invention more comprehensible, the technical solutions in the embodiments of the present invention are described in detail below with reference to the accompanying drawings, and it is apparent that the embodiments described below are only some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, fig. 1 is a flowchart illustrating a method for calculating a valve loss of a DRU inverter according to an embodiment of the invention.
The invention provides a valve loss calculation method of a DRU converter, which comprises the following steps:
and step 101, when a valve side topological diagram of the DRU converter to be analyzed is received, acquiring working condition parameters corresponding to the DRU converter to be analyzed according to a preset period.
The preset period refers to the fundamental wave period of the DRU converter, namely the time for conducting and disconnecting the bridge arm diode in the DRU converter once.
The working condition parameters refer to the working condition information corresponding to the DRU converter to be analyzed.
In the embodiment of the invention, when a valve side topological graph of the DRU converter to be analyzed is received, working condition parameters corresponding to the DRU converter to be analyzed in one fundamental wave period are obtained.
Step 102, determining corresponding diode quantity values according to the valve side topological graph and the working condition parameters.
In the embodiment of the invention, the ideal serial number of the diode modules in the DRU converter is calculated through the valve side no-load line voltage and the reverse breakdown voltage in the working condition parameters, and then the ideal parallel number of the diode modules in the DRU converter is calculated through the maximum circulating current and the allowable circulating current of the bridge arm in the working condition parameters. The number of diode series and the number of diode parallel in the valve side topology map are extracted. When the diode serial number is larger than or equal to the ideal serial number and the diode parallel number is larger than or equal to the ideal parallel number, the diode serial number and the diode parallel number are multiplied to generate a diode number value.
It should be noted that, in the flexible low-frequency system, in order to ensure that the current flowing through each diode does not exceed the maximum current allowed to flow through each diode, the reverse voltage born by each diode does not exceed the reverse breakdown voltage, the serial number of the diodes should be greater than or equal to the ideal serial number, and the parallel number of the diodes should be greater than or equal to the ideal parallel number. When any condition is not satisfied, the extracted diode serial number and the extracted diode parallel number are wrong or the obtained working condition parameters are wrong.
And 103, inputting the working condition parameters into a preset loss analysis model to generate corresponding loss data.
In the embodiment of the invention, working condition parameters are used as input of a preset loss analysis model, and the on-state loss value, the off-state loss value and the switching loss value of the diode are obtained through calculation of the preset loss analysis model.
And 104, determining a valve loss value corresponding to the DRU converter to be analyzed according to the diode quantity value, the period and the loss data.
In the embodiment of the invention, the on-state loss value of the device corresponding to the DRU converter to be analyzed is determined according to the diode quantity value and the on-state loss value of the diode. And determining the device cut-off loss value corresponding to the DRU converter to be analyzed according to the diode quantity value and the diode cut-off loss value. And determining a switching loss value corresponding to the DRU converter to be analyzed according to the fundamental wave period, the diode quantity value and the switching loss value, calculating a device on-state loss value, a device cut-off loss value and a sum value between the switching loss values, and taking the sum value as a valve loss value corresponding to the DRU converter to be analyzed.
In the embodiment of the invention, when a valve side topological graph of a DRU converter to be analyzed is received, working condition parameters corresponding to the DRU converter to be analyzed are obtained according to a preset period, corresponding diode quantity values are determined according to the valve side topological graph and the working condition parameters, the working condition parameters are input into a preset loss analysis model, corresponding loss data are generated, and the valve loss values corresponding to the DRU converter to be analyzed are determined according to the diode quantity values, the period and the loss data. The method and the device solve the technical problems that the valve loss calculation of the DRU mainly builds a corresponding simulation model, the valve loss of the DRU is calculated through the simulation model, the calculation result precision depends on the simulation model precision, the calculation time is long, the method and the device are difficult to apply to a DRU-MMC system with high level number, and the operation reliability of the DRU-MMC system is reduced. According to the invention, through analyzing the valve loss distribution characteristics of the DRU-MMC system topological graph, the accurate calculation is performed by utilizing the diode quantity value, the loss data and the period, and the valve loss value corresponding to the DRU converter to be analyzed is obtained.
Referring to fig. 2, fig. 2 is a flowchart illustrating a method for calculating a valve loss of a DRU inverter according to a second embodiment of the present invention.
The invention provides a valve loss calculation method of a DRU converter, which comprises the following steps:
step 201, when a valve side topological graph of the DRU converter to be analyzed is received, working condition parameters corresponding to the DRU converter to be analyzed are obtained according to a preset period.
In the embodiment of the invention, when a valve side topological graph of the DRU converter to be analyzed is received, working condition parameters corresponding to the DRU converter to be analyzed are obtained according to a fundamental wave period.
It should be noted that, as shown in fig. 3, based on the PSCAD/EMTDC, a low-frequency grid-structured fan offshore wind power ac transmission system based on the flexible low-frequency DRU-MMC converter is built, and a preset period can be acquired from the low-frequency grid-structured fan offshore wind power ac transmission system of the flexible low-frequency DRU-MMC converter to acquire the working condition parameters corresponding to the DRU converter to be analyzed.
It should be noted that, corresponding system parameters can also be obtained from the offshore wind power alternating current transmission system of the low-frequency grid-structured fan of the flexible low-frequency DRU-MMC converter, wherein the system parameters are shown in table 1:
TABLE 1
Step 202, performing ratio processing on the valve side no-load line voltage and the reverse breakdown voltage to generate a first ratio.
In the embodiment of the invention, a first ratio between the valve side no-load line voltage and the reverse breakdown voltage is calculated, and the first ratio is taken as an ideal series number.
It should be noted that the working condition parameters include a valve side no-load line voltage, a reverse breakdown voltage, a bridge arm maximum current and an allowable current, wherein the ac side of the DRU is connected to an offshore ac system, and the voltage is a set known voltage. DRU (DRU)The ac side voltage is the network side voltage of the junction transformer, so this voltage is known; the junction transformer valve side is connected with the AC side of the DRU, and the rated voltage is the voltage of the AC side of the DRU, and can be obtained through calculation. Let rated capacity of the connection transformer be S TN Valve side no-load phase voltage rating U r The short-circuit impedance percentage is u k The short-circuit impedance of the inverter is% Let the rated capacity of the DRU valve side be S N Rated DC voltage of land exchange convertor station is U dN Since DRU adopts 12 pulse wave rectifying circuit formed by connecting 26 pulse wave rectifying circuits in series, rated direct current of land exchange converter station is i dN ＝S N /U dN . Combining a rectification formula of the power grid commutation converter when the conduction angle is 0 DEG:
i.e. valve side no-load line voltage
And 203, performing ratio processing on the maximum circulating current and the allowable circulating current of the bridge arm to generate a second ratio.
In the embodiment of the invention, a second ratio between the maximum circulating current and the allowable circulating current of the bridge arm is calculated, and the second ratio is used as an ideal parallel number.
And 204, extracting the diode serial number and the diode parallel number of the valve side topological graph, wherein the diode serial number is larger than or equal to a first ratio, and the diode parallel number is larger than or equal to a second ratio.
In the embodiment of the invention, the number of diode series and the number of diode parallel of the valve side topological graph are extracted, and the number of diode series and the number of diode parallel are required to be satisfied: the number of diode series is larger than or equal to the ideal number of series, and the number of diode parallel is larger than or equal to the ideal number of parallel.
It should be noted that, referring to fig. 4, for an actual DRU, each bridge arm is formed by serially connecting a large number of diodes, so that the current flowing through each diode does not exceed the maximum current allowed to flow through each diode, and the reverse voltage born by each diode does not exceed the reverse breakdown voltage of each diode, so as to meet the requirements of bridge arm voltage and current, and prevent the diodes from being damaged due to overload. In the ideal parallel model of the diode modules, l is the ideal serial number in the ideal parallel model of the diode modules, and m is the ideal serial number in the ideal parallel model of the diode modules, so that the number of diodes used by one diode module is l x m. If the conditions are not met, the extracted diode serial number and the extracted diode parallel number are wrong or the acquired working condition parameters are wrong.
It should be noted that the device parameters and the switching energy parameters of the diodes from the diode module of fig. 4 are shown in table 2:
TABLE 2
Step 205, multiplying the serial number of the diodes and the parallel number of the diodes to generate a diode number value.
In the embodiment of the invention, the product of the serial number of the diodes and the parallel number of the diodes is processed, and the number of the diodes is measured.
And 206, inputting the working condition parameters into a preset loss analysis model to generate corresponding loss data.
Further, the operating mode data further includes on-state voltage, on-state resistance, on-device current, forward off-voltage, forward off-resistance, and switching characteristic data, the loss analysis model includes an on-state analysis model, an off-state analysis model, and a switching loss analysis model, and step 206 includes the following sub-steps:
s11, inputting the on-state voltage, the on-state resistance and the on-state device current into an on-state analysis model to generate a corresponding diode on-state loss value.
It should be noted that the on-state analysis model specifically includes:
wherein P is Dcon I is the on-state loss value of the diode f To conduct the device current, V f0 Is of on-state voltage, r f Is an on-state resistance.
In the embodiment of the invention, on-state voltage, on-state resistance and on-state device current are used as inputs of an on-state analysis model, and the on-state loss value of the diode is obtained through calculation of the on-state analysis model.
S12, inputting the forward cut-off voltage and the forward cut-off resistance into a cut-off analysis model to generate corresponding diode cut-off loss values.
It should be noted that the cutoff analysis model specifically includes:
wherein P is Doff For the cut-off loss value of the diode, V D For positive cut-off voltage, R Doff Is a forward cut-off resistance.
In the embodiment of the invention, the forward cut-off voltage and the forward cut-off resistance are used as the input of a cut-off analysis model, and the cut-off loss value of the diode is calculated through the cut-off analysis model.
S13, inputting the switching characteristic data and the current of the conducting device into a switching loss analysis model to generate a corresponding switching loss value.
It should be noted that the switching loss analysis model specifically includes:
wherein E is rec The switching loss value is a first switching characteristic coefficient, b is a second switching characteristic coefficient, c is a third switching characteristic coefficient, and k is a temperature correction coefficient.
In the embodiment of the invention, the switching characteristic data and the current of the conducting device are used as the input of a switching loss analysis model, and the switching loss value is obtained through calculation of the switching loss analysis model.
The switching loss analysis model was calculated using a switching characteristic curve given by the device manufacturer. And obtaining the change relation between the loss of the device and the temperature through fitting a curve and linear interpolation.
S14, adopting a diode on-state loss value, a diode off-state loss value and a switching loss value as loss data.
In the embodiment of the invention, the on-state loss value, the off-state loss value and the switching loss value of the diode are output as loss data.
Step 207, determining a valve loss value corresponding to the DRU converter to be analyzed according to the diode quantity value, the period and the loss data.
Further, step 207 comprises the sub-steps of:
s21, multiplying the diode quantity value with a preset first working condition threshold value to generate a first multiplied value.
In the embodiment of the present invention, in a specific implementation, in order to facilitate implementation of the method, the above process may be converted into a form of formula encapsulation, and the expression mode of the first multiplication value is as follows:
A 1 ＝6*D zs ；
wherein A is 1 For the first multiplication, D zs Is the diode count value.
S22, multiplying the first multiplication value with a preset second working condition threshold value to generate a second multiplication value.
In the embodiment of the present invention, in a specific implementation, in order to facilitate implementation of the method, the above process may be converted into a form of formula encapsulation, and the expression mode of the second multiplier is as follows:
A 2 ＝2*A 1 ；
wherein A is 2 Is a second multiplier.
S23, multiplying the first multiplication value and the diode on-state loss value to generate a device on-state loss value.
In the embodiment of the invention, the first multiplication value and the diode on-state loss value are subjected to product processing to obtain the device on-state loss value.
S24, multiplying the first multiplication value and the diode cut-off loss value to generate a device cut-off loss value.
In the embodiment of the invention, the first multiplication value and the diode cut-off loss value are subjected to multiplication processing to obtain the device cut-off loss value.
S25, multiplying the second multiplication value and the switching loss value to generate a third multiplication value.
S26, performing ratio processing on the third multiplication value and the period to generate a switching loss value.
In the embodiment of the invention, in a specific implementation, in order to facilitate the implementation of the method, the above process may be converted into a form of formula encapsulation, and the expression mode of the switching loss value is as follows:
P sw_DRU ＝A 2 *E rec /T；
wherein P is sw_DRU Is the switching loss value, T is the period, E rec Is the switching loss value.
And S27, adding the switching loss value, the device on-state loss value and the device off-state loss value to generate a threshold loss value corresponding to the DRU converter to be analyzed.
In the embodiment of the invention, the sum value among the switching loss value, the device on-state loss value and the device off-state loss value is calculated, and the sum value is used as the valve loss value corresponding to the DRU converter to be analyzed.
It should be noted that, depending on the generation mechanism, the valve loss of DRU can be decomposed into dynamic loss and static loss. The dynamic loss is the switching loss, and is the loss generated by the on-off action of the diode. For a diode, its turn-on loss is much smaller than its reverse recovery loss, so only the latter is considered in the valve loss calculation of the present application. The rest loss is static loss, mainly comprises 4 aspects of on-state loss, off-state loss, energy storage element loss and constant power load loss, and the proportion of the on-state loss, the off-state loss, the energy storage element loss and the constant power load loss is small and can be ignored.
5-7, a corresponding simulation platform is built in electromagnetic transient simulation software PSCAD/EMTDC to simulate a marine wind power alternating current transmission system model of a DRU-MMC-based low-frequency grid-structured fan. Fig. 4 is a schematic diagram of simulation results of ac voltage effective values at ac side of the DRU converter. Fig. 5 is a schematic diagram of dc voltage simulation results of a DRU inverter. From this, simulation results prove the accuracy of the calculation method of the present invention by simulation and the calculation method of the present invention for the table 3.
TABLE 3 Table 3
In the embodiment of the invention, when a valve side topological graph of a DRU converter to be analyzed is received, working condition parameters corresponding to the DRU converter to be analyzed are obtained according to a preset period, corresponding diode quantity values are determined according to the valve side topological graph and the working condition parameters, the working condition parameters are input into a preset loss analysis model, corresponding loss data are generated, and the valve loss values corresponding to the DRU converter to be analyzed are determined according to the diode quantity values, the period and the loss data. The method and the device solve the technical problems that the valve loss calculation of the DRU mainly builds a corresponding simulation model, the valve loss of the DRU is calculated through the simulation model, the calculation result precision depends on the simulation model precision, the calculation time is long, the method and the device are difficult to apply to a DRU-MMC system with high level number, and the operation reliability of the DRU-MMC system is reduced. According to the invention, through analyzing the valve loss distribution characteristics of the DRU-MMC system topological graph, the accurate calculation is performed by utilizing the diode quantity value, the loss data and the period, and the valve loss value corresponding to the DRU converter to be analyzed is obtained.
Referring to fig. 8, fig. 8 is a block diagram illustrating a valve loss calculation system of a DRU inverter according to a third embodiment of the present invention.
The invention provides a valve loss calculation system of a DRU converter, which is characterized by being applied to the DRU converter in a flexible low-frequency system and comprising:
the acquiring module 301 is configured to acquire, when receiving a valve side topology diagram of the DRU converter to be analyzed, working condition parameters corresponding to the DRU converter to be analyzed according to a preset period;
the extraction module 302 is configured to determine a corresponding diode number value according to the valve side topology map and the working condition parameter;
the first analysis module 303 is configured to input the working condition parameters into a preset loss analysis model, and generate corresponding loss data;
and the second analysis module 304 is configured to determine a threshold loss value corresponding to the DRU converter to be analyzed according to the diode quantity value, the period and the loss data.
Further, the operating parameters include bridge arm maximum current, valve side no-load line voltage, reverse breakdown voltage and allowable current, and the extracting module 302 includes:
the first ratio submodule is used for carrying out ratio processing on the valve side no-load line voltage and the reverse breakdown voltage to generate a first ratio;
the second ratio submodule is used for carrying out ratio processing on the maximum circulating current and the allowable circulating current of the bridge arm to generate a second ratio;
the extraction submodule is used for extracting the diode serial number and the diode parallel number of the valve side topological graph, wherein the diode serial number is larger than or equal to a first ratio, and the diode parallel number is larger than or equal to a second ratio;
and the quantity analysis submodule is used for multiplying the serial number of the diodes and the parallel number of the diodes to generate a diode quantity value.
Further, the working condition data further includes on-state voltage, on-state resistance, on-device current, forward cut-off voltage, forward cut-off resistance, and switching characteristic data, the loss analysis model includes an on-state analysis model, a cut-off analysis model, and a switching loss analysis model, and the first analysis module 303 includes:
the first analysis submodule is used for inputting the on-state voltage, the on-state resistance and the on-state device current into the on-state analysis model to generate a corresponding diode on-state loss value;
the second analysis submodule is used for inputting the forward cut-off voltage and the forward cut-off resistance into a cut-off analysis model to generate a corresponding diode cut-off loss value;
the third analysis submodule is used for inputting the switching characteristic data and the current of the conducting device into the switching loss analysis model to generate a corresponding switching loss value;
the diode on-state loss value, the diode off-state loss value, and the switching loss value are used as loss data.
Further, the second analysis module 304 includes:
the first product submodule is used for multiplying the diode quantity value with a preset first working condition threshold value to generate a first multiplication value;
the second product submodule is used for multiplying the first multiplication value with a preset second working condition threshold value to generate a second multiplication value;
the third multiplication submodule is used for carrying out multiplication processing on the first multiplication value and the diode on-state loss value to generate a device on-state loss value;
the fourth product submodule is used for multiplying the first multiplication value and the diode cut-off loss value to generate a device cut-off loss value;
a fifth product sub-module, configured to multiply the second multiplication value with the switching loss value to generate a third multiplication value;
the first ratio submodule is used for carrying out ratio processing on the third multiplication value and the period to generate a switching loss value;
and the summing submodule is used for summing the switching loss value, the device on-state loss value and the device off-state loss value to generate a valve loss value corresponding to the DRU converter to be analyzed.
Further, the on-state analysis model is specifically:
wherein P is Dcon I is the on-state loss value of the diode f To conduct the device current, V f0 Is of on-state voltage, r f Is an on-state resistance.
Further, the cutoff analysis model is specifically:
wherein P is Doff For the cut-off loss value of the diode, V D For positive cut-off voltage, R Doff Is a forward cut-off resistance.
Further, the switching loss analysis model is specifically:
wherein E is rec The switching loss value is a first switching characteristic coefficient, b is a second switching characteristic coefficient, c is a third switching characteristic coefficient, and k is a temperature correction coefficient.
It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, which are not repeated herein.
In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods may be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
The above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A method for calculating valve loss of a DRU converter, which is applied to a DRU converter in a flexible low frequency system, comprising:
when a valve side topological graph of a DRU converter to be analyzed is received, working condition parameters corresponding to the DRU converter to be analyzed are obtained according to a preset period;
determining corresponding diode quantity values according to the valve side topological graph and the working condition parameters;
inputting the working condition parameters into a preset loss analysis model to generate corresponding loss data;
and determining a valve loss value corresponding to the DRU converter to be analyzed according to the diode quantity value, the period and the loss data.
2. The method of calculating the valve loss of a DRU inverter according to claim 1, wherein the operating condition parameters include a bridge arm maximum circulating current, a valve side no-load line voltage, a reverse breakdown voltage and an allowable circulating current, and the step of determining the corresponding diode number value according to the valve side topology and the operating condition parameters includes:
performing ratio processing on the valve side no-load line voltage and the reverse breakdown voltage to generate a first ratio;
performing ratio processing on the maximum circulating current of the bridge arm and the allowable circulating current to generate a second ratio;
extracting the diode series number and the diode parallel number of the valve side topological graph, wherein the diode series number is larger than or equal to the first ratio, and the diode parallel number is larger than or equal to the second ratio;
and multiplying the serial number of the diodes and the parallel number of the diodes to generate a diode number value.
3. The method for calculating the valve loss of the DRU inverter according to claim 1, wherein the operating condition data further includes on-state voltage, on-state resistance, on-device current, forward-cut voltage, forward-cut resistance and switching characteristic data, the loss analysis model includes an on-state analysis model, a cut-off analysis model and a switching loss analysis model, and the step of inputting the operating condition parameters into a preset loss analysis model to generate the corresponding loss data includes:
inputting the on-state voltage, the on-state resistance and the on-state device current into the on-state analysis model to generate a corresponding diode on-state loss value;
inputting the forward cut-off voltage and the forward cut-off resistance into the cut-off analysis model to generate a corresponding diode cut-off loss value;
inputting the switching characteristic data and the current of the conducting device into the switching loss analysis model to generate a corresponding switching loss value;
the diode on-state loss value, the diode off-state loss value and the switching loss value are adopted as loss data.
4. The method for calculating the valve loss of the DRU inverter according to claim 3, wherein the on-state analysis model is specifically:
wherein P is Dcon I is the on-state loss value of the diode f To conduct the device current, V f0 Is of on-state voltage, r f Is an on-state resistance.
5. The method for calculating the valve loss of the DRU inverter according to claim 3, wherein the cutoff analysis model is specifically:
wherein P is Doff For the cut-off loss value of the diode, V D For positive cut-off voltage, R Doff Is a forward cut-off resistance.
6. The method for calculating the valve loss of the DRU inverter according to claim 3, wherein the switching loss analysis model is specifically:
wherein E is rec The switching loss value is a first switching characteristic coefficient, b is a second switching characteristic coefficient, c is a third switching characteristic coefficient, and k is a temperature correction coefficient.
7. The method of calculating the valve loss of a DRU converter as claimed in claim 3, wherein said step of determining the valve loss value corresponding to said DRU converter to be analyzed based on said diode count value, said period and said loss data comprises:
multiplying the diode quantity value with a preset first working condition threshold value to generate a first multiplied value;
multiplying the first multiplication value with a preset second working condition threshold value to generate a second multiplication value;
multiplying the first multiplication value with the diode on-state loss value to generate a device on-state loss value;
multiplying the first multiplication value and the diode cut-off loss value to generate a device cut-off loss value;
multiplying the second multiplication value with the switching loss value to generate a third multiplication value;
performing ratio processing on the third multiplication value and the period to generate a switching loss value;
and adding the switching loss value, the device on-state loss value and the device off-state loss value to generate a valve loss value corresponding to the DRU converter to be analyzed.
8. A valve loss calculation system for a DRU inverter, for use in a flexible low frequency system, comprising:
the acquisition module is used for acquiring working condition parameters corresponding to the DRU converter to be analyzed according to a preset period when receiving the valve side topological graph of the DRU converter to be analyzed;
the extraction module is used for determining corresponding diode quantity values according to the valve side topological graph and the working condition parameters;
the first analysis module is used for inputting the working condition parameters into a preset loss analysis model to generate corresponding loss data;
and the second analysis module is used for determining a valve loss value corresponding to the DRU converter to be analyzed according to the diode quantity value, the period and the loss data.
9. The DRU inverter valve loss calculation system of claim 8, wherein the operating parameters include bridge arm maximum circulating current, valve side no-load line voltage, reverse breakdown voltage and allowable circulating current, the extraction module comprising:
the first ratio submodule is used for carrying out ratio processing on the valve side no-load line voltage and the reverse breakdown voltage to generate a first ratio;
the second ratio submodule is used for performing ratio processing on the maximum circulating current of the bridge arm and the allowable circulating current to generate a second ratio;
the extraction submodule is used for extracting the diode serial number and the diode parallel number of the valve side topological graph, wherein the diode serial number is larger than or equal to the first ratio, and the diode parallel number is larger than or equal to the second ratio;
and the quantity analysis submodule is used for multiplying the serial number of the diodes and the parallel number of the diodes to generate a diode quantity value.
10. The DRU inverter valve loss calculation system of claim 8, wherein the operating condition data further includes on-state voltage, on-state resistance, on-device current, forward off-voltage, forward off-resistance, and switching characteristic data, the loss analysis model includes an on-state analysis model, an off-state analysis model, and a switching loss analysis model, the first analysis module includes:
the first analysis submodule is used for inputting the on-state voltage, the on-state resistance and the on-state device current into the on-state analysis model to generate a corresponding diode on-state loss value;
the second analysis submodule is used for inputting the forward cut-off voltage and the forward cut-off resistance into the cut-off analysis model to generate a corresponding diode cut-off loss value;
the third analysis submodule is used for inputting the switching characteristic data and the current of the conducting device into the switching loss analysis model to generate a corresponding switching loss value;
the diode on-state loss value, the diode off-state loss value and the switching loss value are adopted as loss data.
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