CN116505535B - Energy storage system and direct current bus voltage stable control method - Google Patents
Energy storage system and direct current bus voltage stable control method Download PDFInfo
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
- H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/1566—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators with means for compensating against rapid load changes, e.g. with auxiliary current source, with dual mode control or with inductance variation
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/22—The renewable source being solar energy
- H02J2300/24—The renewable source being solar energy of photovoltaic origin
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/28—The renewable source being wind energy
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
Abstract
The invention discloses a method for stably controlling the voltage of a direct current bus of an energy storage system, which comprises the following steps: s1, calculating the load mutation grade of each phase and obtaining the total load mutation grade; s2, calculating the voltage mutation grade of the direct current bus; s3, generating a bidirectional DC-DC regulation level according to the total load abrupt change level and the bus voltage abrupt change level; s4, generating inner and outer ring parameters of the bidirectional DC-DC according to the bidirectional DC-DC regulation level; s5, bidirectional DC-DC loop control is carried out according to the inner ring parameters and the outer ring parameters. The inner ring and outer ring parameters in the bidirectional DC-DC loop are adaptively modified by combining the abrupt load change level and the abrupt bus voltage change level, so that the control parameters are dynamically adjusted along with the magnitude of the abrupt change level, the bus voltage recovery time is short, and the system can quickly reach a stable state.
Description
Technical Field
The invention relates to the technical field of energy storage systems, in particular to a direct-current bus voltage stability control method.
Background
In the direct-current micro-grid or the alternating-current/direct-current micro-grid, the stability of the voltage of the direct-current bus is an important index for representing the stability of an energy storage system, and whether the voltage of the direct-current bus is stable or not represents whether the instantaneous energy of the system is balanced or not. Factors influencing the voltage stability of the direct current bus are mainly: power fluctuation and switching of the distributed power supply, load fluctuation and switching, energy exchange among AC/DC micro-grids and the like. When the voltage of the direct current bus is unstable, the normal operation of various loads can be directly influenced, for example, the action of a protection device can be caused, the whole system can be crashed when the voltage of the direct current bus is serious, and the reliability and the safety of an energy storage system are seriously threatened. The above problems are particularly pronounced when the island-type dc micro-grid is not connected to a large grid, is subject to source, load abrupt changes, or is powering a constant power load.
At present, the common control method of the bidirectional DC-DC converter is as follows: the control method is characterized in that a control mode of combining a bus voltage outer ring with an inductance current inner ring in a bidirectional DC-DC converter is adopted on a control algorithm by adopting single BOOST tube control, when the load is increased instantaneously, the bus voltage is greatly reduced, and particularly in the process of switching from no-load to full-load, bus drop is particularly obvious; when the output power of the distributed power supply fluctuates greatly, such as instantaneously, the bus voltage rises greatly. The degree of sudden change (drop or rise) of the bus voltage is influenced by the size of the bus capacitance and the bidirectional DC-DC control parameter, the sudden change depth and the recovery time of the bus voltage directly influence the signal quality of the inversion output voltage, and the output voltage signal with poor signal quality cannot meet the load demand of a user side.
In the prior art, a control mode of combining a busbar voltage outer ring and an inductance current inner ring is adopted, and adjusting parameters (proportional coefficient) adopted by PI (proportional plus integral derivative) adjustment/PID (proportion integration differentiation) adjustment of the inner ring and the outer ring are adoptedK P Value, integration time K I Value, differential timeK D Value) is fixed. And different values of the two components have different effects on the response speed, steady-state error, anti-interference performance, stability and the like of the regulator, such as: too small a scaling factor makes the system slow to abrupt change, too large a scaling factor makes the system have larger overshoot and generate oscillation, and the stability is deteriorated. The PI/PID control strategy of the fixed regulating parameter has poor stabilizing effect of bus voltage when load and input voltage suddenly change.
Disclosure of Invention
In order to solve the problems, the invention provides a stable control method for the voltage of a direct current bus of an energy storage system, which dynamically adjusts parameters of a bidirectional DC-DC control loop by integrating factors such as a load abrupt change level, a bus voltage abrupt change level and the like, thereby achieving the effect of quickly stabilizing the bus voltage.
The technical scheme provided by the invention for solving the problems is as follows:
a method for controlling the voltage stability of a direct current bus of an energy storage system comprises the following steps:
s1, calculating the load mutation grade of each phase and obtaining the total load mutation grade;
s2, calculating the voltage mutation grade of the direct current bus;
s3, generating a bidirectional DC-DC regulation level according to the total load abrupt change level and the bus voltage abrupt change level;
s4, generating inner and outer ring parameters of the bidirectional DC-DC according to the bidirectional DC-DC regulation level;
and S5, performing bidirectional DC-DC loop control according to the inner and outer loop parameters of the bidirectional DC-DC to stabilize the DC bus voltage.
Further, the calculating the load mutation level of each phase in step S1 includes:
s11, collecting the load instantaneous current of each phase in real time, and calculating the instantaneous current fluctuation rate of the phase by utilizing the load instantaneous current of each phase and the instantaneous standard current of the phase;
s12, filtering the instantaneous current fluctuation rate of the phase;
s13, judging whether the bus voltage is returned to normal, if so, executing a step S15; if not, executing step S14;
s14, judging whether the instantaneous current fluctuation rate after phase filtering is larger than the current phase load abrupt change level, if so, executing the step S15; if not, keeping the phase load mutation grade as the current value;
and S15, updating the phase load abrupt change level to be the instantaneous current fluctuation rate after the filtering process.
Further, the instantaneous current fluctuation ratio in the step S11 is calculated as follows, the instantaneous current fluctuation ratio=the load instantaneous current ++the instantaneous standard current; wherein instantaneous standard current=nominal current 1.414 sin (wt. i )，wt i Represents phase iInverting an angle value of the output voltage over time; i=r, S, T.
Further, the step S12 filters the instantaneous current fluctuation rate of the phase by means of arithmetic average filtering.
Further, the step S13 of determining whether the bus voltage has returned to normal includes:
judging whether the deviation between the real-time bus voltage and the reference bus voltage is within an allowable range, and if so, judging that the bus voltage returns to normal; otherwise, judging that the bus voltage does not return to normal.
Further, the step S2 specifically includes:
s21, collecting bus voltage in real time and filtering for a plurality of times;
s22, calculating the bus voltage deviation amount by using the bus voltage and the bus reference voltage after the step S21 is performed with multiple times of filtering;
s23, obtaining the busbar voltage mutation grade according to the busbar voltage deviation quantity.
Further, the step S3 specifically includes:
and taking the product of the total load abrupt change level and the bus voltage abrupt change level as the bidirectional DC-DC regulation level.
Further, the step S4 specifically includes:
s41, pre-manufacturing a set of verified bidirectional DC-DC inner and outer ring parameters;
s42, determining new inner and outer ring parameters to be validated from the set of bidirectional DC-DC inner and outer ring parameters manufactured in the step S41 according to the bidirectional DC-DC regulation level;
s43, if the two-phase DC-DC regulation level generated in the step S3 is greater than the two-way DC-DC regulation level in the previous state, the inner and outer ring parameters to be validated in the step S42 are validated immediately and the inner and outer ring parameters in use are assigned; otherwise, a slow-changing operation is provided between the inner and outer ring parameters to be validated and the inner and outer ring parameters in use to reduce loop oscillation.
The present application also provides an energy storage system comprising: the device comprises an energy storage battery, a bidirectional DC-DC converter, a direct current bus and a load;
the energy storage battery is connected with the bidirectional DC-DC converter;
the bidirectional DC-DC converter comprises a bus capacitor, and the bus capacitor is connected with the direct current bus;
the load comprises an ac load; the alternating current load is connected with the direct current bus through a bidirectional DC-AC converter;
the bidirectional DC-DC converter stabilizes the DC bus voltage by using the energy storage system DC bus voltage stabilization control method.
Further, the system is a single-phase energy storage system or a three-phase energy storage system; when the system is a single-phase energy storage system, calculating a single-phase load mutation level and taking the single-phase load mutation level as a total load mutation level; and when the system is a three-phase energy storage system, calculating the load mutation level of each phase and obtaining the three-phase total load mutation level.
Compared with the prior art, the invention has the beneficial effects that:
adaptively modifying inner and outer loop parameters in a bi-directional DC-DC loop by combining load ramp levels and bus voltage ramp levels such that control parameters (scaling factorK P Value, integration timeK I Value, differential timeK D One or more of the values) dynamically adjusts with mutation class size; the larger the load abrupt change level/the larger the bus voltage abrupt change level, the larger the generated bidirectional DC-DC regulation level is, the shorter the bus voltage recovery time is, the better the voltage performance parameters of inversion output are, the system can quickly reach a stable state, the contradiction between the rapidity and the overshoot of the traditional PI/PID controller is relieved, the balance requirement of the rapidity and the stability is well met, and the voltage signal quality under the condition of abrupt change of the load abrupt change/the distributed power supply power is improved. In addition, the bidirectional DC-DC loop control method can quickly stabilize the bus voltage, so that the requirement of the system on the supporting function of the bus capacitor is reduced, the configuration of the bus capacitor can be reduced, and the effect of reducing the system cost is achieved.
Generating a bidirectional DC-DC regulation level by further utilizing the product of the load abrupt change level and the bus voltage abrupt change level, which is equivalent to further amplification; when the abrupt change level is larger, the bidirectional DC-DC regulation level is multiplied, so that the bus voltage recovery time is further shortened, and the stability of the system is greatly improved.
Drawings
Fig. 1 is a block diagram of an energy storage system according to an embodiment of the present invention.
Fig. 2 is a flowchart of a method for controlling voltage stability of a dc bus of an energy storage system according to an embodiment of the present invention.
Fig. 3 is a block diagram of dual loop control according to an embodiment of the present invention.
Detailed Description
The following describes the present invention in detail. It should be emphasized that the following description is merely exemplary in nature and is in no way intended to limit the scope of the invention or its applications. In addition, in the description of the embodiments of the present invention, "a plurality of times" means two or more times unless specifically defined otherwise.
The invention relates to an energy storage system, the structural block diagram of which is shown in figure 1, comprising: the energy storage battery B1, a bidirectional DC-DC converter, a direct current BUS BUS and a load.
The energy storage battery mainly comprises a Battery Management System (BMS) and an electric core, wherein the BMS is responsible for the functions of battery detection, evaluation, protection, equalization, communication and the like, and the electric core is responsible for energy storage. The energy storage battery is connected with the bidirectional DC-DC converter. In addition, the energy storage battery may further include a filter capacitor C3.
The bidirectional DC-DC converter comprises a bidirectional DC inductor L1, bidirectional DC buck-boost switching tubes G1 and G2 and bus capacitors C1 and C2. The bidirectional DC-DC converter is used as a charging and discharging unit and is mainly used for controlling the charging and discharging states and the power of the energy storage battery. When the energy of the photovoltaic and other distributed energy sources (not shown in the figure) is surplus, the surplus energy charges the energy storage battery through the bidirectional DC-DC converter; when the energy of the photovoltaic and other distributed energy sources (not shown) is insufficient, the energy storage battery releases electric energy through the bidirectional DC-DC converter. Bidirectional DC-DC converters typically employ a dual loop PI/PID control algorithm of an outer (direct current bus) voltage loop and an inner (bidirectional DC inductor) current loop.
The BUS capacitor C1 and the BUS capacitor C2 jointly form a BUS, the voltage of C1 is positive BUS voltage BUS+, and the voltage of C2 is negative BUS voltage BUS-. The bus capacitors C1 and C2 stabilize the output voltage and provide energy support for output variations.
The LOADs load_l1, load_l2, load_l3, load_n in fig. 1 are all AC LOADs (such as various household appliances like refrigerators, televisions, etc.), and therefore need to be connected to the DC BUS through a bidirectional DC-AC converter.
The bi-directional DC-AC converter includes: switching tubes G3-G12 for realizing three-phase inversion control and inversion inductors L2-L4. The right side of the bidirectional DC-AC converter can be connected with an alternating current load and also can be connected with a power grid. In an AC side input mode, the bidirectional DC-AC converter converts alternating current of a power grid into direct current, prepares for charging an energy storage battery, and has a rectification function; in the AC side output mode, the DC-AC converter converts direct current generated by a photovoltaic and other distributed energy power generation system or an energy storage system into alternating current, and has an inversion function.
In addition, the system may further include a distributed power source (not shown), such as a photovoltaic, fan, fuel cell, micro synchronous motor, etc., which is directly connected to the dc bus.
Fig. 2 is a flowchart of a method for controlling voltage stability of a dc bus of an energy storage system according to an embodiment of the present invention. The method for stabilizing and controlling the voltage of the direct current bus of the energy storage system mainly comprises the following seven steps 1) to 7):
the present embodiment takes a three-phase system with three-phase output as an example, which allows a user to access different loads on each phase of power supply according to the requirements, so that the abrupt change of the load of each phase is different.
1) And calculating the R-phase load mutation grade. The method specifically comprises the following steps of 1.1) to 1.5):
1.1 Collecting R-phase load instantaneous current in real time, and calculating R-phase instantaneous current fluctuation rate, specifically R-phase instantaneous current wave, by using the collected R-phase load instantaneous current and R-phase instantaneous standard currentRate = R-phase load instantaneous current +.r-phase instantaneous standard current, where R-phase instantaneous standard current = R-phase nominal current 1.414 sin (wt R )，wt R Representing the angular value of the R-phase inverted output voltage over time.
1.2 The R-phase instantaneous current fluctuation rate obtained by calculation is filtered, the multiple filtering is to increase the number of samples and reduce the influence of single interference in the algorithm, and the value of the R-phase instantaneous current fluctuation rate after being filtered is denoted as Filter_R. The filtering algorithm can be a median average filtering method, an arithmetic average filtering method, a first-order lag filtering method, a weighted recursive average filtering method and the like; preferably, the arithmetic average filtering method is adopted, sampling is continuously carried out for N times, average value is taken, and in practical application, the selection of N combines smoothness and sensitivity, for example [4,8], and one embodiment of the invention adopts N=6.
1.3 Judging whether the bus voltage is returned to normal, if so, executing the step 1.5); if not, go to step 1.4). In some embodiments of the present invention, the manner of determining whether the bus voltage has returned to normal is: judging whether the deviation between the real-time bus voltage and the reference bus voltage is within an allowable range, and if so, judging that the bus voltage returns to normal; otherwise, judging that the bus voltage does not return to normal. In the embodiment of the invention, the bus voltage reference value Wei 700V, the allowable deviation range between the real-time bus voltage and the reference bus voltage is [ -10V,10V ].
1.4 Judging whether the filtered R-phase instantaneous current fluctuation rate Filter_R is larger than the R-phase load mutation level currently in use, if so, executing the step 1.5); if not, the R-phase load abrupt change level r_wave is maintained as the current value, and the formula is expressed as r_wave=r_wave_current.
1.5 The value of the R-phase load sudden change level r_wave is updated to be the R-phase instantaneous current fluctuation rate after the filtering process, that is, filter_r is assigned to the R-phase load sudden change level, and the formula is expressed as r_wave=filter_r.
The bus voltage returns to normal means that the deviation from the bus voltage target value is smaller, namely when the current voltage is near the bus voltage target value, the fluctuation rate is small under the working condition, and the PI/PID control parameters which are given later are not excessively large in order to obtain more stable voltage, so that the device can be directly used; the bus voltage does not return to normal, and the fluctuation is larger, so that the primary purpose is that the abrupt change value is quickly regulated back to the normal value range, and the PI/PID control parameter is only increased but not reduced.
And calculating the S-phase load mutation grade. The method specifically comprises the following steps of 2.1) to 2.5):
2.1 Collecting the S-phase load instantaneous current in real time, and calculating the S-phase instantaneous current fluctuation rate by utilizing the collected S-phase load instantaneous current and the S-phase instantaneous standard current, specifically, the S-phase instantaneous current fluctuation rate=the S-phase load instantaneous current/the S-phase instantaneous standard current, wherein the S-phase instantaneous standard current=the S-phase nominal current 1.414 sin (wt.) S )，wt S Representing the angular value of the S-phase inverted output voltage over time.
2.2 The calculated S-phase instantaneous current fluctuation rate is filtered, the multiple filtering is used for increasing the number of samples and reducing the influence of single interference in the algorithm, and the value of the S-phase instantaneous current fluctuation rate after being filtered is recorded as Filter_S. The filtering algorithm adopted here is the same as the previous 1.2), and will not be described again.
2.3 Judging whether the bus voltage is returned to normal, if so, executing the step 2.5); if not, go to step 2.4). In this step, whether the bus voltage has returned to normal is determined in the same way as in the previous 1.3), and the description thereof is omitted.
2.4 Judging whether the filtered S-phase instantaneous current fluctuation rate Filter_S is larger than the current S-phase load mutation level, if so, executing the step 2.5); if not, keeping the S-phase load mutation level S_Wave as a current value, wherein the formula is expressed as S_Wave=S_Wave_current;
2.5 Updating the value of the S-phase load sudden change level s_wave to be the S-phase instantaneous current fluctuation rate after the filtering process, that is, assigning filter_s to the S-phase load sudden change level, and the formula is expressed as s_wave=filter_s.
3) And calculating the T-phase load mutation grade. The method specifically comprises the following steps of 3.1) to 3.5):
3.1 Real-time acquisition of T-phase load transientsCalculating a T-phase instantaneous current fluctuation rate by using the collected T-phase load instantaneous current and the T-phase instantaneous standard current, specifically, the T-phase instantaneous current fluctuation rate=the T-phase load instantaneous current/the T-phase instantaneous standard current, wherein the T-phase instantaneous standard current=the T-phase nominal current 1.414 sin (wt. T )，wt T An angle value representing the change of the T-phase inversion output voltage along with time;
3.2 The T-phase instantaneous current fluctuation rate obtained by calculation is filtered, the multiple filtering is to increase the number of samples and reduce the influence of single interference in the algorithm, and the value of the T-phase instantaneous current fluctuation rate after being filtered is denoted as Filter_T. The filtering algorithm adopted here is the same as the previous 1.2), and will not be described again.
3.3 Judging whether the bus voltage is returned to normal, if so, executing the step 3.5); if not, go to step 3.4). In this step, whether the bus voltage has returned to normal is determined in the same way as in the previous 1.3), and the description thereof is omitted.
3.4 Judging whether the filtered T-phase instantaneous current fluctuation rate Filter_T is larger than the current T-phase load mutation level, if so, executing the step 3.5); if not, the T-phase load abrupt change level t_wave is maintained as the current value, and the formula is expressed as t_wave=t_wave_current.
3.5 The value of the T-phase load sudden change level t_wave is updated to be the T-phase instantaneous current fluctuation rate after the filtering process, that is, the filter_t is assigned to the T-phase load sudden change level, and the formula is expressed as t_wave=filter_t.
4) Summing the R phase Load mutation level R_Wave, the S phase Load mutation level S_Wave and the T phase Load mutation level T_Wave obtained through calculation to obtain a total Load mutation level, and marking the total Load mutation level as load_Wave, namely:
。
as described above, the total load sudden change level obtained by calculating for the three-phase system, it is understood that the energy storage system may be a single-phase energy storage system, and when the system is a single-phase energy storage system, only the load sudden change level of the phase is calculated and used as the total load sudden change level.
5) And calculating the direct current Bus voltage mutation level bus_wave. The method specifically comprises the following steps of 5.1) to 5.3):
5.1 The direct current bus voltage is collected in real time and is filtered for a plurality of times. The multiple filtering is to increase the number of samples and reduce the influence of single interference in the algorithm, and the bus voltage is recorded as a filter_V after filtering; the filtering algorithm can be a median average filtering method, an arithmetic average filtering method, a first-order lag filtering method, a weighted recursive average filtering method and the like; preferably, an arithmetic average filtering method is adopted, sampling is continuously carried out for N times, an average value is obtained, in practical application, N is selected to be compatible with smoothness and sensitivity, and the value [4,8] is obtained, and in the example, N=6 is obtained.
5.2 Using 5.1) to calculate the Bus voltage deviation delta_V by using the Bus voltage filter_V and the Bus reference voltage bus_Ref after multiple times of filtering, wherein the specific formula is as follows:
where abs is the absolute function of the integer.
5.3 Dividing the Bus voltage abrupt change level bus_wave according to the Bus voltage deviation delta_v.
Since the total Load sudden change level load_wave obtained in the foregoing step is a proportional value (corresponding to the level division), the Bus voltage deviation delta_v is divided into the Bus voltage sudden change levels bus_wave for unification and more facilitating the calculation in the subsequent step 6). Specifically, the levels are classified according to a preset Bus voltage deviation amount threshold, two different deviation amount thresholds are provided in one embodiment, and the corresponding levels are classified into three levels of 1, 2 and 3 from small to large according to deviation, which is denoted as bus_wave. In one embodiment, deviations less than 20V are defined as class 1, within [20V,40V ] as class 2, and greater than 40V as class 3. For example, when the Bus voltage deviation delta_v=18v (less than 20V) calculated in step 5.2), the Bus voltage abrupt change level bus_wave=1.
In another embodiment, the Bus voltage deviation delta_v may also be directly assigned to the Bus voltage step bus_wave.
6) And generating a bidirectional DC-DC regulation Level bus_level according to the Bus voltage abrupt change Level bus_wave determined by the steps and the total Load abrupt change Level load_wave obtained by calculation.
In one embodiment, the product is formulated as: bus_level=bus_wave. The final value of bus_level is preferably an integer value, and if the maximum value is defined as 9, the bus_level is known to vary from 0 to 9 by using the 4-house 5-in principle.
In other embodiments, the sum may be formulated as:
。
and when the abrupt change level is larger, the bidirectional DC-DC regulation level is multiplied, and the internal and external ring parameters generated in the subsequent step 7) are more favorable for shortening the bus voltage recovery time.
7) And generating inner and outer loop parameters (namely an outer loop parameter and an inner loop parameter) of the bidirectional DC-DC according to the bidirectional DC-DC regulation Level bus_level.
The bidirectional DC-DC converter generally adopts double-loop PI/PID regulation of a voltage outer loop and a current inner loop, as shown in fig. 3, the voltage outer loop is used for ensuring stability of output voltage, a bus reference voltage is set on the voltage outer loop, a current given value is obtained by PI/PID by making difference with actual bus voltage, a modulation wave is obtained by PI/PID by making difference with actual current, and a PWM wave control switch is generated to be closed for realizing control. The inner and outer ring parameters are PI parameters or PID parameters, the PI parameters refer to the proportional coefficient (K) in proportional integral adjustment P Value) and integration time (K I Value), the PID parameter refers to the proportional coefficient (K) in the proportional integral derivative adjustment P Value), integration time (K I Value) and differential time (K D Values). In the prior art, the parameters of the inner ring and the outer ring are fixed. While the present embodiment is achieved by integrating load abrupt changes and the likeThe step and bus voltage abrupt change step obtain bidirectional DC-DC regulation step, and the inner and outer ring parameters in the bidirectional DC-DC loop are adaptively modified according to the bidirectional DC-DC regulation step, so that the control parameters are dynamically regulated along with the magnitude of the abrupt change step.
Step 7) specifically includes 7.1) to 7.3) as follows:
7.1 A set of fully verified bidirectional DC-DC inner and outer ring PI parameters or PID parameters are prefabricated according to engineering experience and stored in a memory chip with a memory function such as an EEPROM (Electrically Erasable Programmable read only memory, electrified erasable programmable read-only memory) and the like. The set of empirical bi-directional DC-DC inner and outer loop PI/PID parameters comprises multiple sets of inner and outer loop PI/PID parameters. For example, an exemplary embodiment includes 10 sets of inner and outer ring PI parameters, each set consisting of one inner ring PI parameter and one outer ring PI parameter;
7.2 And (3) determining new inner and outer ring parameters to be validated from the set of the bidirectional DC-DC inner and outer ring parameters manufactured in the step 7.1) according to the bidirectional DC-DC regulation Level bus_level generated in the step 6). In one embodiment, each bidirectional DC-DC regulation Level corresponds to 10 sets of inner and outer ring PI parameters, specifically, for example, the current bus_level is 5, then the 6 th set is selected from the 10 sets of inner and outer ring PI parameters as the new inner and outer ring PI parameters to be validated, and then further judging whether to be validated according to the subsequent step 7.3).
7.3 If the newly generated diphase DC-DC regulation level is greater than the regulation level of the previous state, assigning the used inner and outer ring parameters by utilizing the inner and outer ring parameters to be validated in the step 7.2), and immediately validating; otherwise, a ramp operation is provided between the inner and outer ring parameters to be validated and the inner and outer ring parameters being used, for example, the inner and outer ring PI parameters being used are directionally reduced at fixed intervals to reduce loop oscillation.
In summary, according to the method for stabilizing and controlling the voltage of the direct current bus of the energy storage system, provided by the embodiment of the invention, through integrating the load abrupt change level and the bus voltage abrupt change level, the parameters of the bidirectional DC-DC control loop are dynamically adjusted, the effect of quickly stabilizing the bus is achieved, and the voltage signal quality under the condition of abrupt load change is improved. In addition, the requirement of the system on the supporting function of the bus capacitor is reduced, and the configuration of the bus capacitor can be further reduced, so that the effect of reducing the cost of the system is achieved.
The foregoing is a further detailed description of the invention in connection with the preferred embodiments, and it is not intended that the invention be limited to the specific embodiments described. It will be apparent to those skilled in the art that several equivalent substitutions and obvious modifications can be made without departing from the spirit of the invention, and the same should be considered to be within the scope of the invention.
Claims (8)
1. The method for stably controlling the voltage of the direct current bus of the energy storage system is characterized by comprising the following steps:
s1, calculating the load mutation grade of each phase and obtaining the total load mutation grade;
the calculating of the load mutation level of each phase in step S1 includes:
s11, collecting the load instantaneous current of each phase in real time, and calculating the instantaneous current fluctuation rate of the phase by utilizing the load instantaneous current of each phase and the instantaneous standard current of the phase;
s12, filtering the instantaneous current fluctuation rate of the phase;
s13, judging whether the bus voltage is returned to normal, if so, executing a step S15; if not, executing step S14;
s14, judging whether the instantaneous current fluctuation rate after phase filtering is larger than the current phase load abrupt change level, if so, executing the step S15; if not, keeping the phase load mutation grade as the current value;
s15, updating the phase load abrupt change level to be the instantaneous current fluctuation rate after filtering treatment;
summing the calculated load mutation levels of each phase to obtain the total load mutation level;
s2, calculating the voltage mutation grade of the direct current bus;
the step S2 specifically comprises the following steps:
s21, collecting the voltage of a direct current bus in real time and performing multiple filtering;
s22, calculating the bus voltage deviation amount by using the bus voltage and the bus reference voltage after the step S21 is performed with multiple times of filtering;
s23, obtaining a busbar voltage mutation grade according to the busbar voltage deviation quantity;
s3, generating a bidirectional DC-DC regulation level according to the total load abrupt change level and the bus voltage abrupt change level;
s4, generating inner and outer ring parameters of the bidirectional DC-DC according to the bidirectional DC-DC regulation level;
and S5, performing bidirectional DC-DC loop control according to the inner and outer loop parameters of the bidirectional DC-DC to stabilize the DC bus voltage.
2. The method of claim 1, wherein:
the instantaneous current fluctuation ratio in the step S11 is calculated as follows, the instantaneous current fluctuation ratio=the load instantaneous current ∈the instantaneous standard current; wherein instantaneous standard current=nominal current 1.414 sin (wt. i )，wt i An angle value representing the change of the i-phase inversion output voltage along with time; i=r, S, T.
3. The method of claim 1, wherein said step S12 filters the instantaneous current ripple of the phase using arithmetic average filtering.
4. The method of claim 1, wherein the step S13 of determining whether the bus voltage has returned to normal comprises:
judging whether the deviation between the real-time bus voltage and the reference bus voltage is within an allowable range, and if so, judging that the bus voltage returns to normal; otherwise, judging that the bus voltage does not return to normal.
5. The method according to claim 1, wherein the step S3 specifically includes:
and taking the product of the total load abrupt change level and the bus voltage abrupt change level as the bidirectional DC-DC regulation level.
6. The method according to claim 1, wherein the step S4 specifically includes:
s41, pre-manufacturing a set of verified bidirectional DC-DC inner and outer ring parameters;
s42, determining new inner and outer ring parameters to be validated from the set of verified bidirectional DC-DC inner and outer ring parameters manufactured in the step S41 according to the bidirectional DC-DC regulation level;
s43, if the two-phase DC-DC regulation level generated in the step S3 is greater than the two-way DC-DC regulation level in the previous state, the inner and outer ring parameters to be validated in the step S42 are validated immediately and the inner and outer ring parameters in use are assigned; otherwise, a slow-changing operation is provided between the inner and outer ring parameters to be validated and the inner and outer ring parameters in use to reduce loop oscillation.
7. An energy storage system, comprising: the system comprises an energy storage battery, a bidirectional DC-DC converter, a direct current bus and a load;
the energy storage battery is connected with the bidirectional DC-DC converter;
the bidirectional DC-DC converter comprises a bus capacitor, and the bus capacitor is connected with the direct current bus;
the load is connected with the direct current bus;
the bidirectional DC-DC converter stabilizes the DC bus voltage using the energy storage system DC bus voltage stabilization control method of any one of claims 1 to 6.
8. The energy storage system of claim 7, wherein the system is a single-phase energy storage system or a three-phase energy storage system; when the system is a single-phase energy storage system, the step S1 calculates the load mutation level of the single phase and takes the load mutation level as the total load mutation level; when the system is a three-phase energy storage system, the step S1 calculates the load abrupt change level of each phase and obtains the three-phase total load abrupt change level.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2084357A (en) * | 1980-09-22 | 1982-04-07 | Borg Warner | Stabilizing Circuit for Controlled Inverter-Motor System |
| JP2014018011A (en) * | 2012-07-11 | 2014-01-30 | Nec Toshiba Space Systems Ltd | Voltage transient suppression circuit |
| CN104660074A (en) * | 2015-03-19 | 2015-05-27 | 朱鹏程 | Virtual flux-based coordination control method for direction powder of PWM rectifier |
| CN111969594A (en) * | 2020-05-20 | 2020-11-20 | 国网山东省电力公司青岛供电公司 | Control method and system of back-to-back converter |
| EP3883113A1 (en) * | 2020-03-20 | 2021-09-22 | Mitsubishi Electric R & D Centre Europe B.V. | A method for on-line monitoring a dc-bus capacitor |
| CN114204812A (en) * | 2020-09-17 | 2022-03-18 | 比亚迪股份有限公司 | Method, device, medium and terminal for processing voltage fluctuation of DC/DC converter |
| CN114448071A (en) * | 2022-02-09 | 2022-05-06 | 中南大学 | Bus voltage self-adaptive adjustment method and system of super-capacitor energy storage system |
| CN116207729A (en) * | 2022-12-29 | 2023-06-02 | 北京机电工程研究所 | Method for suppressing busbar oscillation of multi-voltage-class direct-current power distribution network and converter |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10401885B2 (en) * | 2017-08-18 | 2019-09-03 | Rolls-Royce North American Technologies Inc. | DC to DC converter output bus voltage control system |
-
2023
- 2023-06-26 CN CN202310757552.6A patent/CN116505535B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2084357A (en) * | 1980-09-22 | 1982-04-07 | Borg Warner | Stabilizing Circuit for Controlled Inverter-Motor System |
| JP2014018011A (en) * | 2012-07-11 | 2014-01-30 | Nec Toshiba Space Systems Ltd | Voltage transient suppression circuit |
| CN104660074A (en) * | 2015-03-19 | 2015-05-27 | 朱鹏程 | Virtual flux-based coordination control method for direction powder of PWM rectifier |
| EP3883113A1 (en) * | 2020-03-20 | 2021-09-22 | Mitsubishi Electric R & D Centre Europe B.V. | A method for on-line monitoring a dc-bus capacitor |
| CN111969594A (en) * | 2020-05-20 | 2020-11-20 | 国网山东省电力公司青岛供电公司 | Control method and system of back-to-back converter |
| CN114204812A (en) * | 2020-09-17 | 2022-03-18 | 比亚迪股份有限公司 | Method, device, medium and terminal for processing voltage fluctuation of DC/DC converter |
| CN114448071A (en) * | 2022-02-09 | 2022-05-06 | 中南大学 | Bus voltage self-adaptive adjustment method and system of super-capacitor energy storage system |
| CN116207729A (en) * | 2022-12-29 | 2023-06-02 | 北京机电工程研究所 | Method for suppressing busbar oscillation of multi-voltage-class direct-current power distribution network and converter |
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