A method and system for calculating loss of a controllable phase-changing valve under different operating modes

Abstract

A method and system for calculating the loss of a controllable phase-changing valve under different operating modes, including: obtaining the component parameters and operating conditions of each sub-valve of the controllable phase-changing valve under different operating modes; calculating the low-voltage IGBT valve loss, main thyristor valve loss and bypass thyristor valve loss; establishing a simulation model, controlling different sub-valves to be put into operation under different operating modes, analyzing the composition of the loss of each sub-valve under different modes, and simulating the loss of each sub-valve under different operating modes; comparing the simulated low-voltage IGBT valve loss, main thyristor valve loss and bypass thyristor valve loss with the calculated corresponding losses, and taking the larger value as the loss of the corresponding sub-valve; adding the losses of each sub-valve under different operating modes to obtain the loss of the controllable phase-changing valve under different operating modes. The present invention can accurately calculate the loss of a controllable phase-changing valve combined with semi-controlled and fully controlled devices by combining simulation and calculation, thereby improving the accuracy of calculation.

Description

Technical Field

[0001] The present invention belongs to the technical field of loss calculation, and more specifically, relates to a method and system for calculating the loss of a controllable phase-changing valve under different operating modes. Background Art

[0002] When the controllable phase-changing valve is in operation, the main components that generate losses include thyristors, resistors, saturated reactors, etc. The loss mechanisms of these devices are different. Under different load levels and operating conditions, the operating parameters and stresses of the above main components are not exactly the same, so the losses are also different. In addition, the controllable phase-changing valve adopts a new topological structure and combines the comprehensive application of semi-controlled and fully controlled devices, making its equipment type more complex than conventional DC transmission valves. Under different operating modes, the loss generation mechanism is also different, so how to accurately determine the loss of the valve becomes the focus and difficulty in the design.

[0003] CN117498418A provides a method, system, device and medium for optimizing loss reduction of LCC-HVDC, which obtains loss parameters of subcomponents, derives voltage and current values ​​of each node of the subcomponents, establishes a mathematical loss model, calculates the loss of each component, combines the input value and output value of the model, obtains a loss characteristic random forest prediction model, takes the converter trigger control angle, commutation angle and transformer ratio as decision variables, establishes a loss optimization mathematical model, and solves to obtain the optimal parameter combination.

[0004] CN117929898A provides a method and device for measuring the action loss of a clamping circuit of a power module of a flexible DC power transmission converter valve. The method obtains the current flowing through a clamping diode, a clamping resistor and a clamping capacitor in the clamping circuit under different load currents and the voltage at both ends; calculates the loss energy of the clamping resistor according to the resistance value of the clamping resistor and the voltage at both ends of the clamping resistor, calculates the loss energy of the clamping capacitor according to the internal resistance of the clamping capacitor and the current flowing through the clamping capacitor, and calculates the loss energy of the clamping diode according to the voltage at both ends of the clamping diode and the current flowing through the clamping diode; and obtains the action loss energy of the clamping circuit according to the loss energy of the clamping resistor, the loss energy of the clamping capacitor and the loss energy of the clamping diode.

[0005] However, the prior art does not calculate the losses of the new controllable phase-changing valve that combines semi-controlled and fully controlled devices, but only calculates the losses of the valve or thyristor. In addition, the prior art only uses models or current, voltage and resistance to calculate the losses, without considering the inaccuracy of the calculation in complex environments and under different operating conditions. Summary of the invention

[0006] In order to address the deficiencies in the prior art, the present invention provides a method and system for calculating the losses of a controllable phase-changing valve under different operating modes, simulates sub-valves that lack internal operating characteristics, calculates other sub-valves with known topological structures and operating characteristics, and also simulates these sub-valves, corrects the calculation results and simulation results, and finally calculates the losses of the controllable phase-changing valve under different operating modes.

[0007] The present invention adopts the following technical solution.

[0008] The first aspect of the present invention provides a method for calculating the loss of a controllable phase-changing valve under different operating modes, which is characterized by comprising the following contents:

[0009] Obtaining component parameters and operating conditions of each sub-valve of the controllable phase-changing commutation valve under different operating modes; the different modes include CLCC operating mode and LCC operating mode, and the sub-valves include a main thyristor valve, a low-voltage IGBT valve, a bypass thyristor valve, a high-voltage IGBT valve, and a high-voltage thyristor;

[0010] According to the obtained component parameters and operating conditions of different operating modes, the low-voltage IGBT valve loss, main thyristor valve loss and bypass thyristor valve loss are calculated;

[0011] According to the topological structure of the controllable phase-changing valve, a simulation model of the controllable phase-changing valve is established, the component parameters of each sub-valves of the controllable phase-changing valve are set and the operation mode is adjusted. For different operation modes, different sub-valves are controlled to be put into operation. The composition of the loss of each sub-valve under different operation modes is analyzed according to the sub-valves put into operation, and the loss of each sub-valve under different operation modes is obtained by simulation based on the composition;

[0012] The low-voltage IGBT valve loss, main thyristor valve loss and bypass thyristor valve loss obtained by simulation are compared with the corresponding losses calculated based on the obtained component parameters and operating conditions, and the larger value is taken as the loss corresponding to each sub-valve;

[0013] According to the composition of the losses of each sub-valve under different operating modes, the losses of each sub-valve under different operating modes are added together to obtain the losses of the controllable phase-changing valve under different operating modes.

[0014] Preferably, the operating conditions include converter station load, system frequency, DC current, arc extinction angle, trigger angle, commutation angle, converter transformer winding voltage. When obtaining the converter station load, first obtain the converter station predicted load curve. If there is a converter station predicted load with a proportion of more than 80% in the curve, then the load is the converter station rated load. Otherwise, the converter station predicted load with the highest proportion before the preset number N in the curve is taken, and the converter station load is for:

[0015]

[0016] In the formula, is the proportion of the predicted load of the ith converter station with the highest proportion in the predicted load curve of the converter station; Forecast the load for the i-th converter station with the highest proportion.

[0017] Preferably, the low voltage IGBT valve loss is calculated as:

[0018]

[0019] In the formula, is the loss coefficient, is the IGBT temperature coefficient, N t is the number of IGBTs connected in series in the low-voltage IGBT valve; U 0 is the average on-state voltage drop of IGBT; R 0 is the average on-state resistance of the IGBT, μ This is the commutation angle under the operating conditions at this time; I d is the DC current passing through the converter bridge, is the converter station load, is the rated load of the converter station.

[0020] Preferably, the main thyristor valve loss and the bypass thyristor valve loss are calculated as:

[0021] The calculation formulas for the main thyristor valve loss and the bypass thyristor valve loss are:

[0022]

[0023] In the formula, is the conduction loss of the corresponding sub-valve; is the DC current consumption of the corresponding sub-valve; is the damping loss of the corresponding sub-valve; is the shut-off loss of the corresponding sub-valve; is the saturated reactor loss of the corresponding sub-valve; the conduction loss of the corresponding sub-valve is the conduction loss of the thyristor of the corresponding sub-valve plus the conduction loss of other components, and the calculation formula is:

[0024] In the formula, It is the loss coefficient generated during the full conduction of the thyristor silicon wafer. N t is the number of series thyristor stages in the corresponding sub-valve; U 0 is the average on-state voltage drop of the thyristor; R 0is the average on-state resistance of the thyristor, μ is the commutation angle; I d is the DC current passing through the converter bridge; T is the ambient temperature; is the converter station load, is the rated load of the converter station, To remove the sum of the DC resistance of all reactors between the two ends of the thyristor external valve, To remove the sum of all the connected busbar resistances between the two ends of the thyristor external valve, It is the sum of all contact resistances between the two ends of the thyristor external valve.

[0025] Preferably, the DC current loss and damping loss are calculated as:

[0026] The DC current loss calculation formula is:

[0027]

[0028] In the formula, R EQ is the sum of DC voltage-equalizing resistors; is the effective value of the converter transformer winding voltage;

[0029] The damping loss is the sum of the high-frequency damping loss and the low-frequency damping loss. The damping loss calculation formula is:

[0030]

[0031] In the formula, C AC is the effective damping capacitance value at both ends of the main thyristor valve, R AC is the effective damping resistance value connected in series with the effective damping capacitor at both ends of the main thyristor valve; The trigger angle of the controllable phase-changing valve; is the total capacitance of all voltage balancing and damping circuits between the two ends of the main thyristor valve; is the stray capacitance of the converter transformer winding and bushing connected to the main thyristor valve end. μ is the commutation angle; is the system frequency.

[0032] Preferably, the turn-off loss is calculated as:

[0033] When the current i of the thyristor of the corresponding sub-valve passes through zero, measure the instantaneous change value of the current di / dt;

[0034] The turn-off loss calculation formula is:

[0035]

[0036] In the formula, is the system frequency, Q rr is the average value of the stored charge of the thyristor, and di / dt is the instantaneous change of the current measured when the current of the thyristor passes through zero; U R It is the reverse voltage that the valve withstands at the moment of closing. λ is the arc extinction angle, L x is the commutation inductance, N R is the number of saturated reactors corresponding to the sub-valve, L R is the power frequency inductance value of a single saturated reactor.

[0037] Preferably, for different operation modes, different sub-valves are controlled to be put into operation, and the composition of the loss of each sub-valve in different operation modes is analyzed according to the sub-valves put into operation, specifically:

[0038] When operating in CLCC mode, the main thyristor valve, low-voltage IGBT valve, high-voltage IGBT valve and high-voltage thyristor valve in the controllable phase-changing commutation valve are all in operation, and the bypass thyristor valve is in a closed state; the losses of the main thyristor valve and high-voltage thyristor valve in operation include the thyristor loss, resistive loss and saturated reactor loss of the corresponding sub-valve; the low-voltage IGBT valve and high-voltage IGBT valve in operation include the IGBT conduction loss and resistive loss of the corresponding sub-valve; the bypass thyristor valve in the closed state generates resistive loss when the controllable phase-changing commutation valve is subjected to voltage;

[0039] When operating in LCC mode, the main thyristor valve and the bypass thyristor valve are both in operation state, and the low-voltage IGBT valve, high-voltage IGBT valve and high-voltage thyristor valve are all in the closed state; the loss of the bypass thyristor valve in the operation state includes the thyristor loss and resistive loss of the sub-valve; the low-voltage IGBT valve in the closed state does not generate loss, the high-voltage IGBT valve in the closed state generates resistive loss when the controllable phase-changing valve end is subjected to voltage, and the high-voltage thyristor valve in the closed state generates resistive loss and saturated reactor loss when the controllable phase-changing valve end is subjected to voltage.

[0040] Preferably, the loss of each sub-valve under different operation modes is obtained according to the composition simulation, specifically:

[0041] According to the composition simulation, the losses of each sub-valve under different operation modes are obtained as follows:

[0042] The thyristor loss, resistive loss and saturated reactor loss of each sub-valve under different modes are simulated and calculated, and the loss of each sub-valve under different operating modes is calculated according to the composition of the loss of each sub-valve under different operating modes;

[0043] The simulation process of thyristor loss for all sub-valves with thyristor loss is the same, that is, the single-stage thyristor of each sub-valves with thyristor loss is simulated for opening and closing, and the single-stage thyristor voltage curve during the opening and closing of the single-stage thyristor is obtained, as well as the current curve of the sum of the thyristor current and the reverse recovery current. The integrals of these two curves are calculated respectively, and the two integrals are multiplied by the number of thyristor series stages of each sub-valves with thyristor loss to obtain the corresponding thyristor loss of each sub-valves with thyristor loss.

[0044] The simulation process of IGBT conduction loss of all sub-valves with IGBT conduction loss is the same, that is, the single-stage IGBT opening and closing of various sub-valves with IGBT conduction loss are simulated, and the single-stage IGBT voltage curve and single-stage IGBT current curve during the single-stage IGBT opening and closing period are obtained, and the integrals of these two curves are calculated respectively, and these two integrals are multiplied and then multiplied by the number of IGBT series stages of various sub-valves with IGBT conduction loss to obtain the corresponding IGBT conduction loss of various sub-valves with IGBT conduction loss;

[0045] The resistive loss simulation process for all sub-valves with resistive loss is the same, which is to simulate the loss of the damping resistor, the voltage-sharing resistor and the energy-taking resistor in the sub-valves with resistive loss;

[0046] The simulation process of saturated reactor loss is the same for all sub-valves with saturated reactor loss, and the simulation is performed by establishing a reactor equivalent circuit.

[0047] Preferably, the establishment of a reactor equivalent circuit for simulation is specifically as follows:

[0048] The reactor equivalent circuit consists of winding resistance R 0 , leakage inductance L 0 , Nonlinear Iron Core Inductor L SR and nonlinear core resistance R SR Composition, winding resistance R 0 With leakage inductance L 0 After being connected in series with the nonlinear iron core inductor L SR and nonlinear core resistance R SR The parallel structure is connected in series.

[0049] For the saturated reactors of various sub-valves with saturated reactor losses, the valve arm voltage jump caused by the opening and closing of all sub-valves is simulated, resulting in the saturated reactor winding resistance of the corresponding sub-valves with saturated reactor losses. R 0 and core resistance R SR The two accumulated powers are the coil loss and core loss corresponding to the operation of various sub-valves with saturated reactor losses. The sum of the coil loss and the core loss multiplied by the number of saturated reactors corresponding to the various sub-valves with saturated reactor losses is the saturated reactor loss corresponding to the various sub-valves with saturated reactor losses.

[0050] The second aspect of the present invention provides a loss calculation system for a controllable phase-changing valve under different operating modes according to the loss calculation method of the first aspect of the present invention, comprising a component parameter and operating condition acquisition module, a sub-valve loss calculation module, a sub-valve simulation calculation module, a simulation and calculation mutual calibration module, and a controllable phase-changing valve loss calculation module, characterized in that:

[0051] Component parameter and operating condition acquisition module: obtains component parameters and operating conditions of each sub-valve of the controllable phase-changing commutation valve under different operating modes; the different modes include CLCC operating mode and LCC operating mode, and the sub-valves include main thyristor valve, low-voltage IGBT valve, bypass thyristor valve, high-voltage IGBT valve, and high-voltage thyristor;

[0052] Sub-valve loss calculation module: Calculates low-voltage IGBT valve loss, main thyristor valve loss and bypass thyristor valve loss based on the component parameters and operating conditions of different operating modes;

[0053] Sub-valve simulation calculation module: According to the topological structure of the controllable phase-changing valve, a simulation model of the controllable phase-changing valve is established, the component parameters of each sub-valve of the controllable phase-changing valve are set and the operation mode is adjusted. For different operation modes, different sub-valves are controlled to be put into operation, and the composition of the loss of each sub-valve under different operation modes is analyzed according to the sub-valves put into operation. The loss of each sub-valve under different operation modes is simulated according to the composition;

[0054] Simulation and calculation mutual calibration module: compare the low-voltage IGBT valve loss, main thyristor valve loss and bypass thyristor valve loss obtained by simulation with the corresponding losses calculated according to the obtained component parameters and operating conditions, and take the larger value as the loss corresponding to each sub-valve;

[0055] Controllable phase-changing valve loss calculation module: Add the losses of each sub-valve under different operating modes to obtain the losses of the controllable phase-changing valve under different operating modes.

[0056] The third aspect of the present invention proposes a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it uses the steps of a method for calculating losses in different operating modes of a controllable phase-changing valve as described in the first aspect of the present invention.

[0057] The beneficial effect of the present invention is that, compared with the prior art, the present invention calculates the low-voltage IGBT valve loss, main thyristor valve loss and bypass thyristor valve loss of known topological structure and electrical characteristics, takes into account the changes of temperature and load in the calculation, and the main thyristor valve loss and bypass thyristor valve loss calculation take into account the conduction loss, DC current loss, damping loss, turn-off loss and saturated reactor loss, so the calculation takes into account a wide range and has a high accuracy; and the low-voltage IGBT valve, main thyristor valve and bypass thyristor valve and the high-voltage IGBT valve and high-voltage thyristor valve with unknown electrical characteristics are simulated. Real test, for different operation modes, control different sub-valves to be put into operation, analyze the composition of each sub-valve loss under different operation modes according to the sub-valves put into operation, and simulate the loss of each sub-valve under different operation modes according to the composition; taking into account the different losses of each sub-valve under different operation modes, not only the loss of the sub-valve in the operation state is calculated, but also the sub-valve in the closed state when the controllable phase-changing valve end is subjected to voltage. When the controllable phase-changing valve end is subjected to voltage, as the sub-valve voltage fluctuates, a weak operating current will still be generated in the circuit, causing the sub-valve in the closed state to also generate losses. The larger value of the calculated and simulated losses is taken as the final loss, which further improves the accuracy of the obtained loss, and can accurately calculate the loss of the controllable phase-changing valve combined with semi-controlled and fully controlled devices in different modes, which is convenient for the subsequent design of water cooling of the controllable phase-changing valve and improves safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 is a flow chart of the method of the present invention;

[0059] Figure 2 The simulation model diagram of the controllable phase-changing valve

[0060] Figure 3 This is the simulation result diagram of single-stage thyristor loss of main thyristor valve;

[0061] Figure 4 This is the simulation result diagram of single-stage IGBT tube loss of low-voltage IGBT valve;

[0062] Figure 5 This is the topological diagram of the equivalent circuit of the reactor. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only embodiments of a part of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0064] like Figure 1 As shown, embodiment 1 of the present invention proposes a method for calculating the loss of a controllable phase-changing valve under different operating modes, which is characterized by comprising the following contents:

[0065] Obtaining component parameters and operating conditions of each sub-valve of the controllable phase-changing commutation valve under different operating modes; the different modes include CLCC operating mode and LCC operating mode, and the sub-valves include a main thyristor valve, a low-voltage IGBT valve, a bypass thyristor valve, a high-voltage IGBT valve, and a high-voltage thyristor;

[0066] It should be noted that when performing simulation and calculation, the threshold voltage of thyristor and IGBT devices U T0 , slope resistance r T , as well as the resistance and capacitance of each resistor and capacitor, the inductance and saturation characteristics of the saturated reactor and other component parameters are obtained by referring to the device technical manual and electrical design results provided by the device supplier.

[0067] According to the obtained component parameters and operating conditions of different operating modes, the low-voltage IGBT valve loss, main thyristor valve loss and bypass thyristor valve loss are calculated;

[0068] like Figure 2 As shown, according to the topological structure of the controllable phase-changing valve, a simulation model of the controllable phase-changing valve is established, the component parameters of each sub-valves of the controllable phase-changing valve are set and the operation mode is adjusted. For different operation modes, different sub-valves are controlled to be put into operation, and the composition of the loss of each sub-valve under different operation modes is analyzed according to the sub-valves put into operation. The loss of each sub-valve under different operation modes is obtained by simulation based on the composition;

[0069] The low-voltage IGBT valve loss, main thyristor valve loss and bypass thyristor valve loss obtained by simulation are compared with the corresponding losses calculated based on the obtained component parameters and operating conditions, and the larger value is taken as the loss corresponding to each sub-valve;

[0070] According to the composition of the losses of each sub-valve under different operating modes, the losses of each sub-valve under different operating modes are added together to obtain the losses of the controllable phase-changing valve under different operating modes.

[0071] Preferably, the operating conditions include converter station load, system frequency, DC current, arc extinction angle, trigger angle, commutation angle, converter transformer winding voltage. When obtaining the converter station load, first obtain the converter station predicted load curve. If there is a converter station predicted load with a proportion of more than 80% in the curve, then the load is the converter station rated load. Otherwise, the converter station predicted load with the highest proportion before the preset number N in the curve is taken, and the converter station load is for:

[0072]

[0073] In the formula, is the proportion of the predicted load of the ith converter station with the highest proportion in the predicted load curve of the converter station; Forecast the load for the i-th converter station with the highest proportion.

[0074] It should be noted that, after testing, the load of the converter station in this embodiment is equal to the rated load of the converter station. The LCC operation mode includes the LCC inverter operation mode and the LCC rectifier operation mode. The loss calculation and simulation methods are the same in these two modes, but the operating conditions are different. Specifically, the LCC inverter operation mode has no trigger angle, and the arc extinction angle of this embodiment is 18°. The LCC rectifier operation mode has no arc extinction angle, and the trigger angle of this embodiment is 15°. Therefore, the loss results calculated later are also different.

[0075] Preferably, the low voltage IGBT valve loss is calculated as:

[0076]

[0077] In the formula, is the loss coefficient, is the IGBT temperature coefficient, N t is the number of IGBTs connected in series in the low-voltage IGBT valve; U 0 is the average on-state voltage drop of IGBT; R 0 is the average on-state resistance of the IGBT, μ This is the commutation angle under the operating conditions at this time; I d is the DC current passing through the converter bridge, is the converter station load, is the rated load of the converter station.

[0078] It should be noted that It is related to the values ​​of the damping resistor and the voltage-equalizing resistor, and is set through experiments. In this embodiment, it is set to 1.09;

[0079] Preferably, the main thyristor valve loss and the bypass thyristor valve loss are calculated as:

[0080] The calculation formulas for the main thyristor valve loss and the bypass thyristor valve loss are:

[0081]

[0082] is the conduction loss of the corresponding sub-valve; is the DC current loss; is the damping loss; Turn-off loss; is the saturated reactor loss; the calculation of the saturated reactor loss is to calculate the hysteresis loss of the saturated reactor;

[0083] Specifically, the hysteresis loss is calculated as:

[0084]

[0085] In the formula, n L is the number of iron cores of the valve reactor in the valve; M is the mass of each core; K is the magnetic loss characteristic; f is the system frequency.

[0086] The conduction loss of the corresponding sub-valve is the conduction loss of the thyristor of the corresponding sub-valve plus the conduction loss of other components. The calculation formula is:

[0087]

[0088] In the formula, It is the loss coefficient generated during the full conduction of the thyristor silicon wafer. N t is the number of series thyristor stages in the corresponding sub-valve; U 0 is the average on-state voltage drop of the thyristor; R 0 is the average on-state resistance of the thyristor, μ is the commutation angle; I d is the DC current passing through the converter bridge; T is the ambient temperature; is the converter station load, is the rated load of the converter station, To remove the sum of the DC resistance of all reactors between the two ends of the thyristor external valve, To remove the sum of all the connected busbar resistances between the two ends of the thyristor external valve, It is the sum of all contact resistances between the two ends of the thyristor external valve. Specifically, Set up through experiments, In this embodiment, it is 0.02.

[0089] Preferably, the DC current loss and damping loss are calculated as:

[0090] The DC current loss calculation formula is:

[0091]

[0092] In the formula, R EQ is the sum of DC voltage-equalizing resistors; is the effective value of the converter transformer winding voltage;

[0093] The damping loss is the sum of the high-frequency damping loss and the low-frequency damping loss. The damping loss calculation formula is:

[0094]

[0095] In the formula, C AC is the effective damping capacitance value at both ends of the main thyristor valve, R AC is the effective damping resistance value connected in series with the effective damping capacitor at both ends of the main thyristor valve; The trigger angle of the controllable phase-changing valve; The total capacitance of all voltage-equalizing and damping circuits between the two ends of the main thyristor valve; is the stray capacitance of the converter transformer winding and bushing connected to the main thyristor valve end. μ is the commutation angle; is the system frequency.

[0096] Preferably, the turn-off loss is calculated as:

[0097] When the current i of the thyristor of the corresponding sub-valve passes through zero, measure the instantaneous change value of the current di / dt;

[0098] The turn-off loss calculation formula is:

[0099]

[0100] In the formula, is the system frequency, Q rr is the average value of the stored charge of the thyristor, and di / dt is the instantaneous change of the current measured when the current of the thyristor passes through zero; U R It is the reverse voltage that the valve withstands at the moment of closing. λ is the arc extinction angle, L x is the commutation inductance, N R is the number of saturated reactors corresponding to the sub-valve,L R is the power frequency inductance value of a single saturated reactor.

[0101] Preferably, for different operation modes, different sub-valves are controlled to be put into operation, and the composition of the loss of each sub-valve in different operation modes is analyzed according to the sub-valves put into operation, specifically:

[0102] As shown in Table 1, when operating in CLCC mode, the main thyristor valve, low-voltage IGBT valve, high-voltage IGBT valve and high-voltage thyristor valve in the controllable phase-changing commutation valve are all in operation, and the bypass thyristor valve is in a closed state; the losses of the main thyristor valve and high-voltage thyristor valve in the operation state include the thyristor loss, resistive loss and saturated reactor loss of the corresponding sub-valve; the low-voltage IGBT valve and high-voltage IGBT valve in the operation state include the IGBT conduction loss and resistive loss of the corresponding sub-valve; the bypass thyristor valve in the closed state generates resistive loss when the controllable phase-changing commutation valve terminal is subjected to voltage;

[0103] When operating in LCC mode, the main thyristor valve and the bypass thyristor valve are both in operation state, and the low-voltage IGBT valve, high-voltage IGBT valve and high-voltage thyristor valve are all in the closed state; the loss of the bypass thyristor valve in the operation state includes the thyristor loss and resistive loss of the sub-valve; the low-voltage IGBT valve in the closed state does not generate loss, the high-voltage IGBT valve in the closed state generates resistive loss when the controllable phase-changing valve end is subjected to voltage, and the high-voltage thyristor valve in the closed state generates resistive loss and saturated reactor loss when the controllable phase-changing valve end is subjected to voltage.

[0104] Table 1 Loss composition of controllable phase-changing valve

[0105]

[0106] Preferably, the loss of each sub-valve under different operation modes is obtained according to the composition simulation, specifically:

[0107] According to the composition simulation, the losses of each sub-valve under different operation modes are obtained as follows:

[0108] The thyristor loss, resistive loss and saturated reactor loss of each sub-valve under different modes are simulated and calculated, and the loss of each sub-valve under different operating modes is calculated according to the composition of the loss of each sub-valve under different operating modes;

[0109] The simulation process of thyristor loss for all sub-valves with thyristor loss is the same, that is, the single-stage thyristor of each sub-valves with thyristor loss is simulated for opening and closing, and the single-stage thyristor voltage curve during the opening and closing of the single-stage thyristor is obtained, as well as the current curve of the sum of the thyristor current and the reverse recovery current. The integrals of these two curves are calculated respectively, and the two integrals are multiplied by the number of thyristor series stages of each sub-valves with thyristor loss to obtain the corresponding thyristor loss of each sub-valves with thyristor loss.

[0110] Specifically, the single-stage thyristor voltage curve, the current curve of the sum of the thyristor current and the reverse recovery current, and the calculated single-stage thyristor loss of the main thyristor valve of this embodiment are as follows: Figure 3 As shown, the final single-stage thyristor loss is 0.746kW, which is multiplied by the number of thyristor series stages to obtain the thyristor loss of the main thyristor valve.

[0111] The simulation process of IGBT conduction loss of all sub-valves with IGBT conduction loss is the same, that is, the single-stage IGBT opening and closing of various sub-valves with IGBT conduction loss are simulated, and the single-stage IGBT voltage curve and single-stage IGBT current curve during the single-stage IGBT opening and closing period are obtained, and the integrals of these two curves are calculated respectively, and these two integrals are multiplied and then multiplied by the number of IGBT series stages of various sub-valves with IGBT conduction loss to obtain the corresponding IGBT conduction loss of various sub-valves with IGBT conduction loss;

[0112] Specifically, the single-stage thyristor voltage curve, the single-stage IGBT current curve and the calculated single-stage IGBT loss of the low-voltage IGBT valve of this embodiment are as follows: Figure 4 As shown, the final single-stage IGBT loss is 1.098kW, which is multiplied by the number of IGBT series stages to obtain the IGBT on-state loss of the low-voltage IGBT valve.

[0113] The resistive loss simulation process for all sub-valves with resistive loss is the same, which is to simulate the loss of the damping resistor, the voltage-sharing resistor and the energy-taking resistor in the sub-valves with resistive loss;

[0114] The simulation process of saturated reactor loss is the same for all sub-valves with saturated reactor loss, and the simulation is performed by establishing a reactor equivalent circuit.

[0115] Preferably, the establishment of a reactor equivalent circuit for simulation is specifically as follows:

[0116] like Figure 5 As shown, the reactor equivalent circuit consists of the winding resistance R 0 , leakage inductance L 0, Nonlinear Iron Core Inductor L SR and nonlinear core resistance R SR Composition, winding resistance R 0 With leakage inductance L 0 After connecting in series with nonlinear iron core inductor L SR and nonlinear core resistance R SR The parallel structure is connected in series.

[0117] For the saturated reactors of various sub-valves with saturated reactor losses, the valve arm voltage jump caused by the opening and closing of all sub-valves is simulated, resulting in the saturated reactor winding resistance of the corresponding sub-valves with saturated reactor losses. R 0 and core resistance R SR The two accumulated powers are the coil loss and core loss corresponding to the operation of various sub-valves with saturated reactor losses. The sum of the coil loss and the core loss multiplied by the number of saturated reactors corresponding to the various sub-valves with saturated reactor losses is the saturated reactor loss corresponding to the various sub-valves with saturated reactor losses.

[0118] The losses of the main thyristor valve, low-voltage IGBT valve, bypass thyristor valve, high-voltage IGBT valve, and high-voltage thyristor valve obtained by simulation in this embodiment are shown in Tables 2 to 6 respectively;

[0119] Table 2 Simulated losses of the main thyristor valve of the controllable phase-changing valve

[0120]

[0121] Table 3 Simulated losses of low-voltage IGBT valves of controllable phase-changing valves

[0122]

[0123] Table 4 Simulated losses of bypass thyristor valve of controllable phase-changing valve

[0124]

[0125] Table 5 Simulated losses of high-voltage IGBT valves of controllable phase-commutation valves

[0126]

[0127] Table 6 Simulated losses of high-voltage thyristor valves for controllable phase-changing valves

[0128]

[0129] It should be noted that the losses in Tables 2 to 6 are all losses calculated by simulating single-stage components. For example, the thyristor losses in Table 1 are single-stage thyristor losses. To calculate the total loss of the main thyristor valve, it is necessary to multiply the losses in Table 2 by the sum of the series stages of the corresponding components of the sub-valve; all sub-valves are summed up in this way to obtain the total loss simulated by each sub-valve, and the simulation results of the total loss of the low-voltage IGBT valve, the total loss of the main thyristor valve and the total loss of the bypass thyristor valve are compared with the corresponding losses calculated according to the obtained component parameters and operating conditions, and it is obtained that the larger value of the low-voltage IGBT valve loss and the bypass thyristor valve is the simulation result, and the larger value of the main thyristor valve is the result calculated according to the obtained component parameters and operating conditions; the total loss of each sub-valves and the loss of the controllable phase-changing valve are finally obtained as shown in Table 7;

[0130] Table 7 Total losses of each sub-valve and losses of controllable phase-changing valve

[0131]

[0132] Embodiment 2 of the present invention proposes a loss calculation system for a controllable phase-changing valve under different operating modes according to the loss calculation method described in Embodiment 1 of the present invention, including a component parameter and operating condition acquisition module, a sub-valve loss calculation module, a sub-valve simulation calculation module, a simulation and calculation mutual calibration module, and a controllable phase-changing valve loss calculation module, characterized in that:

[0133] Component parameter and operating condition acquisition module: obtains component parameters and operating conditions of each sub-valve of the controllable phase-changing commutation valve under different operating modes; the different modes include CLCC operating mode and LCC operating mode, and the sub-valves include main thyristor valve, low-voltage IGBT valve, bypass thyristor valve, high-voltage IGBT valve, and high-voltage thyristor;

[0134] Sub-valve loss calculation module: Calculates low-voltage IGBT valve loss, main thyristor valve loss and bypass thyristor valve loss based on the component parameters and operating conditions of different operating modes;

[0135] Sub-valve simulation calculation module: According to the topological structure of the controllable phase-changing valve, a simulation model of the controllable phase-changing valve is established, the component parameters of each sub-valve of the controllable phase-changing valve are set and the operation mode is adjusted. For different operation modes, different sub-valves are controlled to be put into operation, and the composition of the loss of each sub-valve under different operation modes is analyzed according to the sub-valves put into operation. The loss of each sub-valve under different operation modes is simulated according to the composition;

[0136] Simulation and calculation mutual calibration module: compare the low-voltage IGBT valve loss, main thyristor valve loss and bypass thyristor valve loss obtained by simulation with the corresponding losses calculated according to the obtained component parameters and operating conditions, and take the larger value as the loss corresponding to each sub-valve;

[0137] Controllable phase-changing valve loss calculation module: Add the losses of each sub-valve under different operating modes to obtain the losses of the controllable phase-changing valve under different operating modes.

[0138] Embodiment 3 of the present invention proposes a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps of a method for calculating losses in different operating modes of a controllable phase-changing valve described in Embodiment 1 of the present invention are used.

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for calculating the loss of a controllable phase-changing valve under different operating modes, characterized in that: Includes the following: Obtaining component parameters and operating conditions of each sub-valve under different operating modes of the controllable phase-changing converter valve; the sub-valves include a main thyristor valve, a low-voltage IGBT valve, a bypass thyristor valve, a high-voltage IGBT valve and a high-voltage thyristor; the different operating modes include a CLCC operating mode and an LCC operating mode, and the operating conditions include a converter station load, a system frequency, a DC current, an arc extinction angle, a trigger angle, a commutation angle, and a converter transformer winding voltage; According to the obtained component parameters and operating conditions, the low-voltage IGBT valve loss, main thyristor valve loss and bypass thyristor valve loss are calculated; according to the controllable phase-changing valve topology, a controllable phase-changing valve simulation model is established, the operating mode is adjusted, and for different operating modes, different sub-valves are controlled to be put into operation, and the composition of the sub-valve losses in each operating state and the locked state under different operating modes is analyzed, among which the bypass thyristor valve in the locked state generates resistive loss when the controllable phase-changing valve end is subjected to voltage; the high-voltage IGBT valve in the locked state generates resistive loss when the controllable phase-changing valve end is subjected to voltage, and the high-voltage thyristor valve in the locked state generates resistive loss and saturated reactor loss when the controllable phase-changing valve end is subjected to voltage, and the loss of each sub-valve in different operating modes is obtained by simulation based on this composition; The low-voltage IGBT valve loss, main thyristor valve loss and bypass thyristor valve loss obtained by simulation are compared with the corresponding calculated losses, and the larger value is taken as the loss of each sub-valve; according to the composition of the loss of each sub-valve in different operating modes, the loss of each sub-valve in different operating modes is added together to obtain the loss in different operating modes.

2. According to claim 1, a method for calculating loss of a controllable phase-changing valve under different operating modes is characterized in that: When obtaining the converter station load, first obtain the converter station predicted load curve. If there is a converter station predicted load that accounts for more than 80% in the curve, then the load is the converter station rated load. Otherwise, take the converter station predicted load with the highest proportion before the preset number N in the curve. The converter station load for: In the formula, is the proportion of the predicted load of the ith converter station with the highest proportion in the predicted load curve of the converter station; Forecast the load for the i-th converter station with the highest proportion.

3. The method for calculating the loss of a controllable phase-changing valve under different operating modes according to claim 2, characterized in that: The calculation of low voltage IGBT valve loss is: In the formula, is the loss coefficient, is the IGBT temperature coefficient, N t is the number of IGBTs connected in series in the low-voltage IGBT valve; U 0 is the average value of IGBT on-state voltage drop; R 0 is the average on-state resistance of IGBT, μ This is the commutation angle under the operating conditions at this time; I d is the DC current passing through the converter bridge, is the converter station load, is the rated load of the converter station.

4. The method for calculating the loss of a controllable phase-changing valve under different operating modes according to claim 2, characterized in that: The calculation of the main thyristor valve loss and the bypass thyristor valve loss is: The calculation formulas for the main thyristor valve loss and the bypass thyristor valve loss are: In the formula, is the conduction loss of the corresponding sub-valve; is the DC current consumption of the corresponding sub-valve; is the damping loss of the corresponding sub-valve; is the shut-off loss of the corresponding sub-valve; is the saturated reactor loss of the corresponding sub-valve; the calculation of the saturated reactor loss is to calculate the hysteresis loss of the saturated reactor; the saturated reactor loss of the bypass thyristor valve loss is 0; The conduction loss of the corresponding sub-valve is the conduction loss of the thyristor of the corresponding sub-valve plus the conduction loss of other components. The calculation formula is: In the formula, It is the loss coefficient generated during the full conduction of the thyristor silicon wafer. N t is the number of series thyristor stages in the corresponding sub-valve; U 0 is the average value of the thyristor on-state voltage drop; R 0 is the average value of the thyristor on-resistance, μ is the commutation angle; I d is the DC current passing through the converter bridge; T is the ambient temperature; is the converter station load, is the rated load of the converter station, To remove the sum of the DC resistance of all reactors between the two ends of the thyristor external valve, To remove the sum of all the connected busbar resistances between the two ends of the thyristor external valve, It is the sum of all contact resistances between the two ends of the thyristor external valve.

5. The method for calculating the loss of a controllable phase-changing valve under different operating modes according to claim 4 is characterized in that: Calculate the DC current loss and damping loss as: The DC current loss calculation formula is: In the formula, R EQ is the sum of DC voltage-equalizing resistors; is the effective value of the converter transformer winding voltage; The damping loss is the sum of the high-frequency damping loss and the low-frequency damping loss. The damping loss calculation formula is: In the formula, C AC is the effective damping capacitance value at both ends of the main thyristor valve, R AC is the effective damping resistance value connected in series with the effective damping capacitor at both ends of the main thyristor valve; The trigger angle of the controllable phase-changing valve; The total capacitance of all voltage-equalizing and damping circuits between the two ends of the main thyristor valve; is the stray capacitance of the converter transformer winding and bushing connected to the main thyristor valve end. μ is the commutation angle; is the system frequency.

6. The method for calculating the loss of a controllable phase-changing valve under different operating modes according to claim 4, characterized in that: The calculated turn-off loss is: When the current i of the thyristor of the corresponding sub-valve passes through zero, measure the instantaneous change value of the current di / dt; The turn-off loss calculation formula is: In the formula, is the system frequency, Q rr is the average value of the stored charge of the thyristor, and di / dt is the instantaneous change of the current measured when the current of the thyristor passes through zero; U R It is the reverse voltage that the valve withstands at the moment of closing. λ is the arc extinction angle, L x is the commutation inductance, N R is the number of saturated reactors corresponding to the sub-valve, L R is the power frequency inductance value of a single saturated reactor.

7. The method for calculating the loss of a controllable phase-changing valve under different operating modes according to claim 1 is characterized in that: The different operating modes are described as controlling different sub-valves to be put into operation, and analyzing the composition of the sub-valve losses in each operating state and the locked state under different operating modes, specifically: when operating in the CLCC mode, the main thyristor valve, the low-voltage IGBT valve, the high-voltage IGBT valve and the high-voltage thyristor valve in the controllable phase-changing commutation valve are all in the operating state, and the bypass thyristor valve is in the locked state; the losses of the main thyristor valve and the high-voltage thyristor valve in the operating state include the thyristor loss, resistive loss and saturated reactor loss of the corresponding sub-valves; the low-voltage IGBT valve and the high-voltage IGBT valve in the operating state include the IGBT conduction loss and resistive loss of the corresponding sub-valve; the bypass thyristor valve in the locked state generates resistive loss when the controllable phase-changing commutation valve terminal is subjected to voltage; When operating in LCC mode, the main thyristor valve and the bypass thyristor valve are both in operation state, and the low-voltage IGBT valve, high-voltage IGBT valve and high-voltage thyristor valve are all in the closed state; the loss of the bypass thyristor valve in the operation state includes the thyristor loss and resistive loss of the sub-valve; the low-voltage IGBT valve in the closed state does not generate loss, the high-voltage IGBT valve in the closed state generates resistive loss when the controllable phase-changing valve end is subjected to voltage, and the high-voltage thyristor valve in the closed state generates resistive loss and saturated reactor loss when the controllable phase-changing valve end is subjected to voltage.

8. The method for calculating the loss of a controllable phase-changing valve under different operating modes according to claim 7, characterized in that: According to the composition simulation, the losses of each sub-valve under different operation modes are obtained as follows: The thyristor loss, resistive loss and saturated reactor loss of each sub-valve under different modes are simulated and calculated, and the loss of each sub-valve under different operating modes is calculated according to the composition of the loss of each sub-valve under different operating modes; The simulation process of thyristor loss for all sub-valves with thyristor loss is the same, that is, the single-stage thyristor of each sub-valves with thyristor loss is simulated for opening and closing, and the single-stage thyristor voltage curve during the opening and closing of the single-stage thyristor is obtained, as well as the current curve of the sum of the thyristor current and the reverse recovery current. The integrals of these two curves are calculated respectively, and the two integrals are multiplied by the number of thyristor series stages of each sub-valves with thyristor loss to obtain the corresponding thyristor loss of each sub-valves with thyristor loss. The simulation process of IGBT conduction loss of all sub-valves with IGBT conduction loss is the same, that is, the single-stage IGBT opening and closing of various sub-valves with IGBT conduction loss are simulated, and the single-stage IGBT voltage curve and single-stage IGBT current curve during the single-stage IGBT opening and closing period are obtained, and the integrals of these two curves are calculated respectively, and these two integrals are multiplied and then multiplied by the number of IGBT series stages of various sub-valves with IGBT conduction loss to obtain the corresponding IGBT conduction loss of various sub-valves with IGBT conduction loss; The resistive loss simulation process for all sub-valves with resistive loss is the same, which is to simulate the loss of the damping resistor, the voltage-sharing resistor and the energy-taking resistor in the sub-valves with resistive loss; The simulation process of saturated reactor loss is the same for all sub-valves with saturated reactor loss, and the simulation is performed by establishing a reactor equivalent circuit.

9. A method for calculating loss of a controllable phase-changing valve under different operating modes according to claim 8, characterized in that: The reactor equivalent circuit is established for simulation, specifically: The reactor equivalent circuit consists of winding resistance R 0. Leakage inductance L 0. Nonlinear iron core inductor L SR and nonlinear core resistance R SR Composition, winding resistance R 0 and leakage inductance L 0 in series with nonlinear iron core inductor L SR and nonlinear core resistance R SR The parallel structure is connected in series. For the saturated reactors of various sub-valves with saturated reactor losses, the valve arm voltage jump caused by the opening and closing of all sub-valves is simulated, resulting in the saturated reactor winding resistance of the corresponding sub-valves with saturated reactor losses. R 0 and core resistance R SR The two accumulated powers are the coil loss and core loss corresponding to the operation of various sub-valves with saturated reactor losses. The sum of the coil loss and the core loss multiplied by the number of saturated reactors corresponding to the various sub-valves with saturated reactor losses is the saturated reactor loss corresponding to the various sub-valves with saturated reactor losses.

10. A loss calculation system for a controllable phase-changing valve under different operating modes according to the loss calculation method according to any one of claims 1 to 9, comprising a component parameter and operating condition acquisition module, a sub-valve loss calculation module, a sub-valve simulation calculation module, a simulation and calculation mutual calibration module, and a controllable phase-changing valve loss calculation module, characterized in that: Component parameter and operating condition acquisition module: obtains component parameters and operating conditions of each sub-valve of the controllable phase-changing commutation valve under different operating modes; the different modes include CLCC operating mode and LCC operating mode, and the sub-valves include main thyristor valve, low-voltage IGBT valve, bypass thyristor valve, high-voltage IGBT valve, and high-voltage thyristor; Sub-valve loss calculation module: Calculates low-voltage IGBT valve loss, main thyristor valve loss and bypass thyristor valve loss based on the component parameters and operating conditions of different operating modes; Sub-valve simulation calculation module: According to the topological structure of the controllable phase-changing valve, a simulation model of the controllable phase-changing valve is established, the component parameters of each sub-valve of the controllable phase-changing valve are set and the operation mode is adjusted. For different operation modes, different sub-valves are controlled to be put into operation, and the composition of the loss of each sub-valve under different operation modes is analyzed according to the sub-valves put into operation. The loss of each sub-valve under different operation modes is simulated according to the composition; Simulation and calculation mutual calibration module: compare the low-voltage IGBT valve loss, main thyristor valve loss and bypass thyristor valve loss obtained by simulation with the corresponding losses calculated according to the obtained component parameters and operating conditions, and take the larger value as the loss corresponding to each sub-valve; Controllable phase-changing valve loss calculation module: Add the losses of each sub-valve under different operating modes to obtain the losses of the controllable phase-changing valve under different operating modes.

11. A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, uses the steps of a method for calculating losses in different operating modes of a controllable phase-changing valve according to any one of claims 1 to 9.

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