Parameter design method and system for differential controller with high dynamic performance

Abstract

The invention provides a parameter design method and system for a high-dynamic-performance differential controller, and the method comprises the steps: determining the internal delay time of the differential controller based on the switching frequency of an energy storage converter in combination with the difficulty degree of delay; step excitation voltages in different directions are applied to a filter inductor and a parasitic resistor on the alternating current side of the energy storage converter, and a first parameter and a second parameter of the differential controller are obtained based on the internal delay time of the differential controller; wherein the amplitude of the response current of the forward step excitation voltage is obtained according to the first parameter and the forward step excitation voltage; compared with parameters obtained through parameter design of a traditional differential controller, the method has the advantage of being high in control precision, the energy storage converter can conduct rapid protection action, and the reliability of the energy storage converter is improved. And the safety of the whole energy storage system is improved.

Description

Technical Field

[0001] The present invention relates to the field of energy storage converter control, and particularly relates to a parameter design method and system for a high-dynamic-performance differential controller. Background Art

[0002] An energy storage system includes electrochemical batteries. Compared with conventional sources such as photovoltaic and wind power, the batteries have the disadvantages of being flammable and explosive, which requires the energy storage converter to have high dynamic performance and be able to act quickly during faults to improve safety. When controlling the energy storage converter, in order to enable the energy storage system to have high dynamic characteristics and suppress the impact current during energy storage system faults, a differential controller is used to control the energy storage converter. Due to the advantage of small calculation amount of the differential controller, the energy storage converter can perform rapid protection actions, which is beneficial to improving the safety of the entire energy storage system.

[0003] Currently, the prior art invention patent "A Current Sensorless Grid-Connected Current Control Method for an Energy Storage Converter" (authorized announcement number CN 108448613_B) proposes an open-loop differential controller, which has the advantage of fast dynamic characteristics compared with existing differential controllers.

[0004] However, this invention patent only gives the structure of the differential controller and does not give the specific design method of the differential controller parameters. Existing implementation methods of differential controllers, such as forward difference, backward difference, bilinear transformation, etc., all have defects. Among them, forward difference uses the value at the next moment and the value at the current moment for difference operation, which is easy to introduce unstable poles and cause the energy storage system to become unstable; backward difference has a large phase gain drop in the high-frequency band and cannot be equivalently a differential anymore; bilinear transformation has a high amplitude gain at high frequencies, introducing high-frequency noise and reducing the quality of the grid-connected current. Most importantly, the above differential implementation methods only consider from the perspective of signal transformation, mechanically apply transformation formulas, do not combine the parameter characteristics of converter components, switching frequencies, etc., and cannot depict the change of the filter inductor current at the moment of switch interruption, resulting in unclear physical meaning and non-intuitive and simple parameter design.

[0005] In summary, the existing differential controllers only propose an optimized structure without giving the corresponding parameter method. Applying the parameters obtained by the traditional parameter design method to the optimized structure of this differential controller will cause problems such as instability of the energy storage system and reduction of the grid-connected current quality. Summary of the Invention

[0006] In order to solve the problems that applying the parameters obtained by the traditional parameter design method to the optimized structure of this differential controller in the prior art will cause instability of the energy storage system and reduction of the grid-connected current quality, the present invention proposes a parameter design method for a high-dynamic-performance differential controller, including:

[0007] Based on the switching frequency of the energy storage converter, determine the internal delay time of the differential controller in combination with the difficulty level of the delay magnitude.

[0008] Apply step excitation voltages in different directions to the filter inductor and parasitic resistance on the AC side of the energy storage converter, and obtain the first parameter and the second parameter of the differential controller based on the internal delay time of the differential controller.

[0009] Wherein, the first parameter and the forward step excitation voltage obtain the amplitude of the response current of the forward step excitation voltage; the second parameter and the reverse step excitation voltage obtain the amplitude of the response current of the reverse step excitation voltage after the internal delay time; the sum of the amplitude of the response current of the forward step excitation voltage and the amplitude of the response current of the reverse step excitation voltage after the internal delay time is equal to the product of the value of the differential of the response current of the combined step excitation voltage at any moment within the delay time and the internal delay time.

[0010] Optionally, the obtaining the first parameter and the second parameter of the differential controller based on the internal delay time of the differential controller includes:

[0011] Based on the internal delay time of the differential controller, construct a first constraint condition where the response currents of step excitation voltages in different directions are equal under the internal delay time.

[0012] Based on the first constraint condition, in combination with the differential of the response current of the combined step excitation voltage, construct a second constraint condition.

[0013] Based on the first constraint condition and the second constraint condition, obtain the first parameter and the second parameter of the differential controller.

[0014] The first constraint condition is: the difference between the final amplitude of the response current of the forward excitation voltage and the amplitude of the response current of the combined step excitation voltage after the internal delay time is equal to the amplitude of the response current of the reverse excitation voltage; the second constraint condition is: the product of the value of the differential of the response current of the combined step excitation voltage at any moment within the delay time and the internal delay time is equal to the sum of the amplitude of the response current of the forward step excitation voltage and the amplitude of the response current of the reverse step excitation voltage after the internal delay time.

[0015] Optionally, the obtaining the first parameter and the second parameter of the differential controller based on the first constraint condition and the second constraint condition includes:

[0016] Based on the second constraint condition, obtain the first parameter.

[0017] Based on the first constraint condition, obtain the proportional relationship between the first parameter and the second parameter.

[0018] Based on the proportional relationship between the first parameter and the second parameter, and the first parameter, the second parameter is obtained.

[0019] Optionally, any moment within the delay time is the moment when the internal delay time is located.

[0020] Optionally, when any moment within the delay time is the moment when the internal delay time is located, the value of the differential of the response current of the combined step excitation voltage at any moment within the delay time is calculated by the following calculation formula:

[0021]

[0022] In the formula, l2 represents the value of the differential of the response current of the combined step excitation voltage at the internal delay time, i 1ref (t) represents the reference current of the energy storage converter, K1 represents the first parameter of the differential controller, L represents the filter inductance and parasitic resistance of the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, ΔT represents the internal delay time, represents a pure delay module.

[0023] Optionally, the first parameter and the second parameter are calculated by the following calculation formula:

[0024]

[0025] In the formula, K1 represents the first parameter of the differential controller, K2 represents the second parameter of the differential controller, ΔT represents the internal delay time, L represents the filter inductance and parasitic resistance of the AC side of the energy storage converter, and R represents the parasitic resistance of the energy storage converter.

[0026] Optionally, the amplitude of the response current of the forward step excitation voltage is calculated by the following calculation formula:

[0027]

[0028] In the formula, i 1ref (t) represents the reference current of the energy storage converter, K1 represents the first parameter of the differential controller, L represents the filter inductance and parasitic resistance of the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, represents a pure delay module, i L1 (t) represents the amplitude of the response current of the forward step excitation voltage at time t.

[0029] Optionally, the amplitude of the response current of the reverse step excitation voltage after the internal delay time is calculated by the following calculation formula:

[0030]

[0031] In the formula, i L2 (t - ΔT) represents the amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time, represents a pure delay module, ΔT represents the internal delay time, K2 represents the second parameter of the differential controller, L represents the filter inductor and parasitic resistance on the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, and i 1ref (t - ΔT) represents the reference current of the energy storage converter after delaying the internal delay time.

[0032] On the other hand, the present invention also proposes a parameter design system for a high-dynamic-performance differential controller, including:

[0033] An internal delay determination module, configured to determine the internal delay time of the differential controller based on the switching frequency of the energy storage converter and in combination with the difficulty level of the delay magnitude;

[0034] A parameter determination module, configured to apply step excitation voltages in different directions to the filter inductor and parasitic resistance on the AC side of the energy storage converter, and obtain the first parameter and the second parameter of the differential controller based on the internal delay time of the differential controller;

[0035] Wherein, the first parameter and the forward step excitation voltage obtain the amplitude of the response current of the forward step excitation voltage; the second parameter and the reverse step excitation voltage obtain the amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time; the sum of the amplitude of the response current of the forward step excitation voltage and the amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time is equal to the product of the value of the differential of the response current of the combined step excitation voltage at any moment within the delay time and the internal delay time.

[0036] Optionally, the parameter determination module obtains the first parameter and the second parameter of the differential controller based on the internal delay time of the differential controller, including:

[0037] Based on the internal delay time of the differential controller, constructing a first constraint condition for the response currents of step excitation voltages in different directions to be equal under the internal delay time;

[0038] Based on the first constraint condition and in combination with the differential of the response current of the combined step excitation voltage, constructing a second constraint condition;

[0039] Based on the first constraint condition and the second constraint condition, obtaining the first parameter and the second parameter of the differential controller;

[0040] The first constraint condition is that the difference between the final amplitude of the response current of the forward excitation voltage and the amplitude of the response current of the combined step excitation voltage after a delay of the internal delay time is equal to the final amplitude of the response current of the reverse excitation voltage; the second constraint condition is that the product of the value of the derivative of the response current of the combined step excitation voltage at any moment within the delay time and the internal delay time is equal to the sum of the amplitude of the response current of the forward step excitation voltage and the amplitude of the response current of the reverse step excitation voltage after a delay of the internal delay time.

[0041] Optionally, the parameter determination module obtains the first parameter and the second parameter of the differential controller based on the first constraint condition and the second constraint condition, including:

[0042] Obtaining the first parameter based on the second constraint condition;

[0043] Obtaining the proportional relationship between the first parameter and the second parameter based on the first constraint condition;

[0044] Obtaining the second parameter based on the proportional relationship between the first parameter and the second parameter and the first parameter.

[0045] Optionally, any moment within the delay time is the moment where the internal delay time is located.

[0046] Optionally, when any moment within the delay time is the moment where the internal delay time is located, the value of the derivative of the response current of the combined step excitation voltage at any moment within the delay time is calculated by the following calculation formula:

[0047]

[0048] In the formula, l2 represents the value of the derivative of the response current of the combined step excitation voltage at the internal delay time, i 1ref (t) represents the reference current of the energy storage converter, K1 represents the first parameter of the differential controller, L represents the filter inductance and parasitic resistance of the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, ΔT represents the internal delay time, represents a pure delay module.

[0049] Optionally, the first parameter and the second parameter are calculated by the following calculation formula:

[0050]

[0051] In the formula, K1 represents the first parameter of the differential controller, K2 represents the second parameter of the differential controller, ΔT represents the internal delay time, L represents the filter inductance and parasitic resistance of the AC side of the energy storage converter, and R represents the parasitic resistance of the energy storage converter.

[0052] Optionally, the amplitude of the response current of the forward step excitation voltage is calculated by the following calculation formula:

[0053]

[0054] wherein, i 1ref (t) represents the reference current of the energy storage converter, K1 represents the first parameter of the differential controller, L represents the filter inductance and parasitic resistance of the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, represents a pure delay module, and i L1 (t) represents the amplitude of the response current of the forward step excitation voltage at time t.

[0055] Optionally, the amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time is calculated by the following calculation formula:

[0056]

[0057] wherein, i L2 (t - ΔT) represents the amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time, represents a pure delay module, ΔT represents the internal delay time, K2 represents the second parameter of the differential controller, L represents the filter inductance and parasitic resistance of the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, and i 1ref (t - ΔT) represents the reference current of the energy storage converter after delaying the internal delay time.

[0058] On the other hand, the present application also provides a computing device, including: one or more processors;

[0059] The processor is configured to execute one or more programs;

[0060] When the one or more programs are executed by the one or more processors, the parameter design method of a high dynamic performance differential controller as described above is implemented.

[0061] On the other hand, the present application also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed, the parameter design method of a high dynamic performance differential controller as described above is implemented.

[0062] Compared with the prior art, the beneficial effects of the present invention are:

[0063] The present invention provides a parameter design method and system for a high-dynamic-performance differential controller, including: determining the internal delay time of the differential controller based on the switching frequency of the energy storage converter and considering the difficulty level of the delay magnitude; applying step excitation voltages in different directions to the AC-side filter inductor and parasitic resistor of the energy storage converter, and obtaining the first parameter and the second parameter of the differential controller based on the internal delay time of the differential controller. Among them, the first parameter and the forward step excitation voltage are used to obtain the amplitude of the response current of the forward step excitation voltage; the second parameter and the reverse step excitation voltage are used to obtain the amplitude of the response current of the reverse step excitation voltage after the internal delay time. The sum of the amplitude of the response current of the forward step excitation voltage and the amplitude of the response current of the reverse step excitation voltage after the internal delay time is equal to the product of the value of the differential of the response current of the combined step excitation voltage at any moment within the delay time and the internal delay time. By determining the internal delay time and then determining the first parameter and the second parameter of the differential controller according to the step excitation voltages in different directions applied to the AC-side filter inductor and parasitic resistor of the energy storage converter, the parameters obtained by the present invention have the advantage of high control accuracy compared with the parameters designed by the traditional differential controller, enabling the energy storage converter to perform rapid protection actions and being beneficial to improving the safety of the entire energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 is a schematic flowchart of a parameter design method for a high-dynamic-performance differential controller proposed by the present invention;

[0065] Figure 2 is a time-domain diagram of step excitation voltages in different directions applied to the AC-side filter inductor and parasitic resistor of the energy storage converter and the response current by the method proposed by the present invention;

[0066] Figure 3 is a schematic structural diagram of the differential controller of the present invention;

[0067] Figure 4 is a time-domain diagram of the combined step excitation voltage applied to the AC-side filter inductor and parasitic resistor of the energy storage converter and the differential of the response current by the method proposed by the present invention;

[0068] Figure 5 is the steady-state characteristic of the energy storage converter after adopting the method proposed by the present invention;

[0069] Figure 6 is the dynamic characteristic of the energy storage converter after adopting the method proposed by the present invention;

[0070] Figure 7 is a schematic structural diagram of a parameter design system for a high-dynamic-performance differential controller proposed by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0071] The present invention proposes a parameter design method and system for a high-dynamic-performance differential controller. Compared with the parameters obtained by the parameter design of traditional differential controllers, it has the advantage of high control accuracy, can enable the energy storage converter to perform rapid protection actions, and is beneficial to improving the safety of the entire energy storage system.

[0072] Embodiment 1:

[0073] A parameter design method for a high-dynamic-performance differential controller, as Figure 1 shown, includes the following steps:

[0074] Step 1: Based on the switching frequency of the energy storage converter, determine the internal delay time of the differential controller in combination with the difficulty level of the delay magnitude.

[0075] Step 2: Apply step excitation voltages in different directions to the filter inductor and parasitic resistance on the AC side of the energy storage converter, and obtain the first parameter and the second parameter of the differential controller based on the internal delay time of the differential controller.

[0076] Among them, the first parameter and the forward step excitation voltage obtain the amplitude of the response current of the forward step excitation voltage; the second parameter and the reverse step excitation voltage obtain the amplitude of the response current of the reverse step excitation voltage after the internal delay time; the sum of the amplitude of the response current of the forward step excitation voltage and the amplitude of the response current of the reverse step excitation voltage after the internal delay time is equal to the product of the value of the differential of the response current of the combined step excitation voltage at any moment within the delay time and the internal delay time.

[0077] In Step 1, based on the switching frequency of the energy storage converter, determine the internal delay time of the differential controller in combination with the difficulty level of the delay magnitude.

[0078] According to the switching frequency of the energy storage converter and the difficulty level of designing the delay magnitude, discuss and analyze the internal delay value of the differential controller, select a suitable internal delay time △T, and △T can also be set artificially. Subsequently, based on the internal delay time, calculate a set of parameters of the differential controller using Step 2, specifically 3 parameters, namely proportional parameter 1 (the first parameter), proportional parameter 2 (the second parameter), and the internal delay time.

[0079] In Step 2, apply step excitation voltages in different directions to the filter inductor and parasitic resistance on the AC side of the energy storage converter, and obtain the first parameter and the second parameter of the differential controller based on the internal delay time of the differential controller.

[0080] Among them, obtaining the first parameter and the second parameter of the differential controller based on the internal delay time of the differential controller includes the following methods:

[0081] ◎ Based on the internal delay time of the differential controller, a first constraint condition is constructed where the response currents of step excitation voltages in different directions are equal under the internal delay time;

[0082] ◎ Based on the first constraint condition, combined with the differential of the response current of the combined step excitation voltage, a second constraint condition is constructed;

[0083] ◎ Based on the first constraint condition and the second constraint condition, the first parameter and the second parameter of the differential controller are obtained;

[0084] The first constraint condition is: the difference between the final amplitude of the response current of the forward excitation voltage and the amplitude of the response current of the combined step excitation voltage after delaying the internal delay time is equal to the final amplitude of the response current of the reverse excitation voltage; the second constraint condition is: the product of the value of the differential of the response current of the combined step excitation voltage at any moment within the delay time and the internal delay time is equal to the sum of the amplitude of the response current of the forward step excitation voltage and the amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time.

[0085] When constructing the first constraint condition, combine Figure 2 and Figure 3 . First, introduce the principle of implementing the differential controller. Figure 2 In, at t = 0, the step excitation voltage M1(t) = K1i 1ref (t) acts on the filter inductor and the parasitic resistance, as shown in Figure 2 (a). Among them, M1(t) represents the excitation voltage, K1 represents the differential controller parameter 1, and i 1ref (t) represents the reference current of the energy storage converter. At this time, a corresponding response current is generated on the L - R, as shown in Figure 2 (b), and its time - domain expression is:

[0086]

[0087] In Equation (1), i 1ref (t) represents the reference current of the energy storage converter, K1 represents the first parameter of the differential controller, L represents the filter inductor and the parasitic resistance on the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, represents a pure delay module, indicating a delay starting from the moment t = 0, and i L1 (t) represents the amplitude of the response current of the forward step excitation voltage at time t. It can be seen that Equation (1) contains K1.

[0088] At t = ΔT, a reverse step excitation voltage M2(t) = K2i 1ref(t - ΔT) acts on L - R, as shown in Figure 2 (c), where M2(t) represents the amplitude of the reverse excitation voltage, K2 represents the differential controller parameter 2, and i 1ref (t - ΔT) represents the reference current after a delay of ΔT.

[0089] The response current is as shown in Figure 2 (d), and its expression is:

[0090]

[0091] In Equation (2), i L2 (t - ΔT) represents the amplitude of the response current of the reverse step excitation voltage after the internal delay time of the delay, represents a pure delay module, indicating that the delay starts from the moment t = ΔT. ΔT represents the internal delay time, K2 represents the second parameter of the differential controller, L represents the filter inductor and parasitic resistance on the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, and i 1ref (t - ΔT) represents the reference current of the energy storage converter after the internal delay time of the delay. It can be seen that K2 is included in Equation (1).

[0092] In Figure 2 (e), the above two excitation voltages are linearly superimposed. When Figure 2 (b), Figure 2 (d) the shaded area, that is, the change in the response current, is equal. According to the principle of linear superposition, Figure 2 the primary combined step excitation voltage shown in (e) can generate a current increase ΔI1 on L - R. By reasonably designing the value of K1 / K2, the current increase ΔI1 can be made equal to the desired current increase ΔI, that is, the response current generated by the primary combined step excitation voltage on L - R is equal to the response current generated by the ideal current controller on L - R. Therefore, under this working condition, the ideal current controller can be equivalent to the control of two step combinations, as shown in Figure 2 .

[0093] From Figure 3 it can be seen that there are three parameters in the differential control, namely the proportional terms K1, K2, and the delay term ΔT (the internal delay time of the differential controller, that is, the time interval between the forward excitation voltage and the reverse excitation voltage).

[0094] Next, the specific design method of the differential control parameters will be given. According to Figure 4 the precondition for the equivalence of the step combination control and the ideal differential control shown, that is, Figure 4 the final amplitude of the response current in (b) is equal to the shaded area in Figure 4 (d), the following relationship can be obtained:

[0095] i L1 (t) t＝∞ -i L1 (t) t＝ΔT =i L2 (t - ΔT) t＝∞ (3)

[0096] In Equation (3), i L1 (t) t＝∞ represents the final amplitude of the response current generated when the positive excitation voltage acts on L - R; i L2 (t - ΔT) t＝∞ represents the final amplitude of the response current generated when the reverse excitation voltage acts on L - R; i L1 (t) t＝ΔT represents the amplitude of the response current generated by the combined excitation voltage on L - R at time ΔT.

[0097] The above constructs the first constraint condition. The following is an explanation of the construction of the second constraint condition:

[0098] Substituting Equations (1) and (2) into (3), we get:

[0099]

[0100] In the equation, represents a pure delay module with a delay time of ΔT, which only represents a fixed delay time. From this, the proportional relationship between the first parameter and the second parameter can be obtained. That is, based on the first constraint condition, the proportional relationship between the first parameter and the second parameter is obtained.

[0101] Within one switching period, the amplitude ΔI1 of the response current generated by the designed differential controller on L - R (which is also Figure 4 the shaded area s in (d)) is:

[0102]

[0103] For Figure 2 (e) ( Figure 2 (e) is the same as Figure 4 (a)), the differential operation of the combined excitation voltage shown can obtain its impulse function, as shown in Figure 4 (c). According to the characteristics of the linear system, the response of this impulse function is the differential of the step - combined excitation voltage response shown in Figure 2 (f), as shown in Figure 4 .

[0104] According to Figure 4 , the differential operation of the response current is performed, Figure 4In (d), the response of the impulse function of the step-combined excitation voltage at the moment t = 0 can be obtained. At this time, there is a relational expression shown in Equation (6):

[0105]

[0106] In the formula, l1 represents the slope of the response current i L1 Similarly, at t = ΔT, the amplitude of the response of the impulse function of the step-combined excitation voltage can be expressed as:

[0107]

[0108] In the formula, l2 represents the slope of the response current i L2 According to the previous analysis, by differentiating the step-combined excitation voltage, its impulse excitation can be obtained. Then, the integral of the impulse excitation response should correspond to the response of the step-excitation combined voltage, that is Figure 4 The increase in the response current ΔI1 in (b) is equal to Figure 4 The shaded area s in (d).

[0109] When ΔT is relatively small, Figure 4 The shaded part in (d) can be approximately equivalent to a rectangle, where the length is ΔT and the height has two values, namely l1 and l2.

[0110] The above is the construction of the second constraint condition. In the second constraint condition, the height of the rectangle selected by the present invention is l1 or l2, and it can also be Figure 4 The height of any point on the curve of (d).

[0111] Thus, according to the second constraint condition, the first parameter can be calculated, that is, based on the second constraint condition, the first parameter is obtained.

[0112] In the present invention, when l1 is selected as the height (equivalent to the long side), at this time Figure 4 The area of the shaded part in (d) can be expressed as:

[0113]

[0114] In Equation (8), s represents the area of the shaded part.

[0115] In the present invention, when l2 is selected as the height (equivalent to the short side), at this time Figure 2 The area of the shaded part in (d) can be expressed as:

[0116]

[0117] By respectively making Equation (5) equal to (8) and (9) to construct the constraint relationship, two different sets of solutions for K1 / K2 can be obtained:

[0118]

[0119]

[0120] As can be seen from the previous analysis, the smaller ΔT is, Figure 2 in (d), the closer l1 and l2 are, the closer the shaded part is to a rectangle, and the smaller the area error obtained by solving will be. In theory, the minimum value of ΔT can be infinitely close to zero, but the constraints of the implementation method should be considered. In actual digital control, for the convenience of implementing the differential controller, ΔT = T s / N can be taken, where N represents the number of samplings in a switching period, and T s is the switching period. Specifically, when the switching frequency is low, multiple samplings (such as N times) can be used to reduce ΔT; when the switching frequency is high, ΔT = T s can be selected.

[0121] Next, the calculation results of the two equivalent methods will be analyzed, and a set of parameters with better performance will be selected as the parameters of the differential control. Let the reference current be i ref (t) = Asin(ωt), where A and ω are the amplitude and angular frequency of the reference current respectively, t represents time, and the output voltage u LR (t) of the ideal current controller can be expressed as

[0122] u LR1 and u LR2 represent the voltages output by the differential controller during the long-side equivalent and the short-side equivalent respectively. Substituting them in, we get:

[0123]

[0125] In the formula, i ref (t - ΔT) represents the reference current i ref (t) delayed by △T.

[0126]

[0127] When the time delay ΔT approaches zero, the following formula holds:

[0128]

[0129] At this time, equations (13) and (14) can be simplified to:

[0130] u LR1 (t) ≈ RA sin(ωt) + ω(L - RΔT)A cos(ωt) (16)

[0131] u LR2(t)≈RA sin(ωt)+ωLA cos(ωt)(17)

[0132] Comparing Eqs. (12), (16), and (17), it can be seen that when the short-side equivalence is adopted (this result is universal), the excitation voltage generated by the differential control is closer to the excitation voltage generated by the ideal differential, and the error of the energy storage converter is smaller. Therefore, the parameter expression form of the final differential controller is as shown in Eq. (11), that is, according to the actual filter element parameters of the energy storage converter, the differential controller parameters can be calculated according to Eq. (11).

[0133] Figure 5 The steady-state characteristics of the energy storage converter after the differential controller parameters are designed using the proposed invention are given. It can be seen that the response current can track the reference current well, proving that with the differential controller designed using the proposed invention, the energy storage converter can achieve better static characteristics.

[0134] Figure 6 The dynamic characteristics of the converter energy storage converter after the differential controller parameters are designed using the proposed invention are given. It can be seen that when the reference current changes suddenly, the response current can quickly track the reference current, proving that with the differential controller designed using the proposed invention, the energy storage converter can achieve better dynamic characteristics.

[0135] Therefore, in the present invention, obtaining the first parameter and the second parameter of the differential controller based on the first constraint condition and the second constraint condition includes:

[0136] Obtaining the first parameter based on the second constraint condition;

[0137] Obtaining the proportional relationship between the first parameter and the second parameter based on the first constraint condition;

[0138] Obtaining the second parameter based on the proportional relationship between the first parameter and the second parameter and the first parameter.

[0139] Wherein, any moment within the delay time is the moment where the internal delay time is located.

[0140] When any moment within the delay time is the moment where the internal delay time is located, the value of the differential of the response current of the combined step excitation voltage at any moment within the delay time is calculated by the following calculation formula:

[0141]

[0142] In the formula, l2 represents the value of the differential of the response current of the combined step excitation voltage at the internal delay time, i 1ref(t) represents the reference current of the energy storage converter, K1 represents the first parameter of the differential controller, L represents the filter inductance and parasitic resistance on the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, ΔT represents the internal delay time, represents a pure delay module.

[0143] In the present invention, the first parameter and the second parameter are calculated by the following calculation formula:

[0144]

[0145] In the formula, K1 represents the first parameter of the differential controller, K2 represents the second parameter of the differential controller, ΔT represents the internal delay time, L represents the filter inductance and parasitic resistance on the AC side of the energy storage converter, and R represents the parasitic resistance of the energy storage converter.

[0146] In the present invention, the amplitude of the response current of the forward step excitation voltage is calculated by the following calculation formula:

[0147]

[0148] In the formula, i 1ref (t) represents the reference current of the energy storage converter, K1 represents the first parameter of the differential controller, L represents the filter inductance and parasitic resistance on the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, represents a pure delay module, i L1 (t) represents the amplitude of the response current of the forward step excitation voltage at time t.

[0149] In the present invention, it is characterized in that the amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time is calculated by the following calculation formula:

[0150]

[0151] In the formula, i L2 (t - ΔT) represents the amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time, represents a pure delay module, ΔT represents the internal delay time, K2 represents the second parameter of the differential controller, L represents the filter inductance and parasitic resistance on the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, i 1ref (t - ΔT) represents the reference current of the energy storage converter after delaying the internal delay time.

[0152] In the process of the experiment of the present invention, by applying excitation voltages with different directions on the L-R, and then under the constraint condition that the response currents of the two excitation voltages are equal after △T; taking the derivative of the response to the step excitation voltage, taking the integral of the response to the derivative of the step excitation voltage, and constructing the constraint condition of equal area; respectively according to the long-side equivalent and short-side equivalent principles, taking the integral of the derivative response of the step excitation voltage to obtain the corresponding area, and discussing the errors of the two methods; the present invention designs the internal delay of the differential controller according to the switching frequency of the energy storage converter and the difficulty of setting the delay.

[0153] In summary, the present invention applies a step excitation voltage on the L-R, establishes the differential transformation of the excitation voltage response and the integral transformation of the derivative response of the excitation voltage, and then constructs the constraint conditions to obtain the parameters of the differential controller. Thus, the present invention designs the parameters of the differential controller for power control in combination with the physical meaning, which has the advantages of clear physical meaning and simple parameter design; at the same time, during the experiment, the errors are discussed to ensure the control accuracy of the system when using the proposed method, and at the same time, the defects of the existing differential implementation methods can be avoided. Therefore, the present invention can clarify the physical meaning of the parameter design of the differential controller for power control, simplify the difficulty of parameter design, and improve the practicability of the differential controller. Therefore, compared with the parameters obtained by the parameter design of the traditional differential controller, it has the advantage of high control accuracy, can make the energy storage converter perform rapid protection actions, and is beneficial to improving the safety of the entire energy storage system.

[0154] Embodiment 2:

[0155] Based on the same inventive concept, the present invention also provides a parameter design system for a high-dynamic-performance differential controller, as Figure 7 shown, including:

[0156] An internal delay determination module, configured to determine the internal delay time of the differential controller based on the switching frequency of the energy storage converter and in combination with the difficulty of the delay magnitude;

[0157] A parameter determination module, configured to apply step excitation voltages with different directions to the AC-side filter inductor and parasitic resistance of the energy storage converter, and obtain the first parameter and the second parameter of the differential controller based on the internal delay time of the differential controller;

[0158] Wherein, the first parameter and the forward step excitation voltage obtain the amplitude of the response current of the forward step excitation voltage; the second parameter and the reverse step excitation voltage obtain the amplitude of the response current of the reverse step excitation voltage after the internal delay time; the sum of the amplitude of the response current of the forward step excitation voltage and the amplitude of the response current of the reverse step excitation voltage after the internal delay time is equal to the product of the value of the derivative of the response current of the combined step excitation voltage at any moment within the delay time and the internal delay time.

[0159] The parameter determination module obtains the first parameter and the second parameter of the differential controller based on the internal delay time of the differential controller, including:

[0160] Based on the internal delay time of the differential controller, a first constraint condition is constructed where the response currents of different-direction step excitation voltages at the internal delay time are equal;

[0161] Based on the first constraint condition, combined with the differential of the response current of the combined step excitation voltage, a second constraint condition is constructed;

[0162] Based on the first constraint condition and the second constraint condition, the first parameter and the second parameter of the differential controller are obtained;

[0163] The first constraint condition is: the difference between the final amplitude of the response current of the forward excitation voltage and the amplitude of the response current of the combined step excitation voltage after delaying the internal delay time is equal to the final amplitude of the response current of the reverse excitation voltage; the second constraint condition is: the product of the value of the differential of the response current of the combined step excitation voltage at any moment within the delay time and the internal delay time is equal to the sum of the amplitude of the response current of the forward step excitation voltage and the amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time.

[0164] The parameter determination module obtains the first parameter and the second parameter of the differential controller based on the first constraint condition and the second constraint condition, including:

[0165] Based on the second constraint condition, the first parameter is obtained;

[0166] Based on the first constraint condition, the proportional relationship between the first parameter and the second parameter is obtained;

[0167] Based on the proportional relationship between the first parameter and the second parameter and the first parameter, the second parameter is obtained.

[0168] Any moment within the delay time is the moment where the internal delay time is located.

[0169] When any moment within the delay time is the moment where the internal delay time is located, the value of the differential of the response current of the combined step excitation voltage at any moment within the delay time is calculated by the following calculation formula:

[0170]

[0171] In the formula, l2 represents the value of the differential of the response current of the combined step excitation voltage at the internal delay time, i 1ref(t) represents the reference current of the energy storage converter, K1 represents the first parameter of the differential controller, L represents the filter inductance and parasitic resistance on the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, ΔT represents the internal delay time, represents a pure delay module.

[0172] The first parameter and the second parameter are calculated by the following calculation formula:

[0173]

[0174] In the formula, K1 represents the first parameter of the differential controller, K2 represents the second parameter of the differential controller, ΔT represents the internal delay time, L represents the filter inductance and parasitic resistance on the AC side of the energy storage converter, and R represents the parasitic resistance of the energy storage converter.

[0175] The amplitude of the response current of the forward step excitation voltage is calculated by the following calculation formula:

[0176]

[0177] In the formula, i 1ref (t) represents the reference current of the energy storage converter, K1 represents the first parameter of the differential controller, L represents the filter inductance and parasitic resistance on the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, represents a pure delay module, i L1 (t) represents the amplitude of the response current of the forward step excitation voltage at time t.

[0178] The amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time is calculated by the following calculation formula:

[0179]

[0180] In the formula, i L2 (t - ΔT) represents the amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time, represents a pure delay module, ΔT represents the internal delay time, K2 represents the second parameter of the differential controller, L represents the filter inductance and parasitic resistance on the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, i 1ref (t - ΔT) represents the reference current of the energy storage converter after delaying the internal delay time.

[0181] Embodiment 3:

[0182] Based on the same inventive concept, the present invention also provides a computer device, which includes a processor and a memory. The memory is used to store a computer program, and the computer program includes program instructions. The processor is used to execute the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, and is suitable for implementing one or more instructions. Specifically, it is suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function, so as to implement the steps of a parameter design method for a high-dynamic performance differential controller in the above embodiments.

[0183] Embodiment 4:

[0184] Based on the same inventive concept, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory). The computer-readable storage medium is a memory device in the computer device and is used to store programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and, of course, the extended storage medium supported by the computer device. The computer-readable storage medium provides a storage space, and the operating system of the terminal is stored in this storage space. And, one or more instructions suitable for being loaded and executed by the processor are also stored in this storage space. These instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The one or more instructions stored in the computer-readable storage medium can be loaded and executed by the processor to implement the steps of a parameter design method for a high-dynamic performance differential controller in the above embodiments.

[0185] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) that contain computer-usable program code.

[0186] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate means for realizing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0187] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including instruction means that realize the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0188] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for realizing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0189] The above are only embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included within the scope of the claims of the present invention pending approval.

Claims

1. A parameter design method for a high-dynamic-performance differential controller, characterized in that, Including: Determine the internal delay time of the differential controller based on the switching frequency of the energy storage converter and the difficulty level of the delay magnitude. Apply step excitation voltages in different directions to the filter inductor and parasitic resistance on the AC side of the energy storage converter, and obtain the first parameter and the second parameter of the differential controller based on the internal delay time of the differential controller. Wherein, the first parameter and the forward step excitation voltage obtain the amplitude of the response current of the forward step excitation voltage; the second parameter and the reverse step excitation voltage obtain the amplitude of the response current of the reverse step excitation voltage after the internal delay time. The sum of the amplitude of the response current of the forward step excitation voltage and the amplitude of the response current of the reverse step excitation voltage after the internal delay time is equal to the product of the value of the differential of the response current of the combined step excitation voltage at any moment within the delay time and the internal delay time.

2. The method according to claim 1, characterized in that, The obtaining of the first parameter and the second parameter of the differential controller based on the internal delay time of the differential controller includes: Based on the internal delay time of the differential controller, construct a first constraint condition where the response currents of step excitation voltages in different directions are equal under the internal delay time. Based on the first constraint condition, combine with the differential of the response current of the combined step excitation voltage to construct a second constraint condition. Based on the first constraint condition and the second constraint condition, obtain the first parameter and the second parameter of the differential controller. The first constraint condition is: the difference between the final amplitude of the response current of the forward excitation voltage and the amplitude of the response current of the combined step excitation voltage after the internal delay time is equal to the amplitude of the response current of the reverse excitation voltage; the second constraint condition is: the product of the value of the differential of the response current of the combined step excitation voltage at any moment within the delay time and the internal delay time is equal to the sum of the amplitude of the response current of the forward step excitation voltage and the amplitude of the response current of the reverse step excitation voltage after the internal delay time.

3. The method according to claim 2, characterized in that, The obtaining of the first parameter and the second parameter of the differential controller based on the first constraint condition and the second constraint condition includes: Based on the second constraint condition, obtain the first parameter. Based on the first constraint condition, obtain the proportional relationship between the first parameter and the second parameter. Based on the proportional relationship between the first parameter and the second parameter and the first parameter, obtain the second parameter.

4. The method according to claim 2, characterized in that, Any moment within the delay time is the moment where the internal delay time is located.

5. The method according to claim 4, characterized in that, When any moment within the delay time is the moment where the internal delay time is located, the value of the differential of the response current of the combined step excitation voltage at any moment within the delay time is calculated by the following calculation formula: Where, l2 represents the value of the differential of the response current of the combined step excitation voltage at the internal delay time, and i 1ref (t) represents the reference current of the energy storage converter, K1 represents the first parameter of the differential controller, L represents the filter inductance and parasitic resistance on the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, and ΔT represents the internal delay time.

6. The method according to claim 5, characterized in that, The first parameter and the second parameter are calculated by the following calculation formula: In the formula, K1 represents the first parameter of the differential controller, K2 represents the second parameter of the differential controller, ΔT represents the internal delay time, L represents the filter inductor and parasitic resistance on the AC side of the energy storage converter, and R represents the parasitic resistance of the energy storage converter.

7. The method according to claim 1, characterized in that, The amplitude of the response current of the forward step excitation voltage is calculated by the following calculation formula: where, i 1ref (t) represents the reference current of the energy storage converter, K1 represents the first parameter of the differential controller, L represents the filtering inductance and parasitic resistance on the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, and i L1 (t) represents the amplitude of the response current of the positive step excitation voltage at time t.

8. The method according to claim 1, characterized in that, The amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time is calculated by the following calculation formula: Where, i L2 (t - ΔT) represents the amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time, ΔT represents the internal delay time, K2 represents the second parameter of the differential controller, L represents the filter inductance and parasitic resistance on the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, and i 1ref (t - ΔT) represents the reference current of the energy storage converter after delaying the internal delay time.

9. A parameter design system for a high-dynamic-performance differential controller, characterized in that, Including: An internal delay determination module, configured to determine the internal delay time of the differential controller based on the switching frequency of the energy storage converter and in combination with the difficulty level of the delay magnitude; A parameter determination module, configured to apply step excitation voltages in different directions to the AC-side filter inductor and parasitic resistance of the energy storage converter, and obtain a first parameter and a second parameter of the differential controller based on the internal delay time of the differential controller; Wherein, the first parameter and the forward step excitation voltage are used to obtain the amplitude of the response current of the forward step excitation voltage; the second parameter and the reverse step excitation voltage are used to obtain the amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time; The sum of the amplitude of the response current of the forward step excitation voltage and the amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time is equal to the product of the value of the differential of the response current of the combined step excitation voltage at any moment within the delay time and the internal delay time.

10. The system according to claim 9, wherein, The parameter determination module obtains the first parameter and the second parameter of the differential controller based on the internal delay time of the differential controller, including: Based on the internal delay time of the differential controller, a first constraint condition for the response currents of step excitation voltages in different directions to be equal under the internal delay time is constructed; Based on the first constraint condition and in combination with the differential of the response current of the combined step excitation voltage, a second constraint condition is constructed; Based on the first constraint condition and the second constraint condition, the first parameter and the second parameter of the differential controller are obtained; The first constraint condition is: the difference between the final amplitude of the response current of the forward excitation voltage and the amplitude of the response current of the combined step excitation voltage after delaying the internal delay time is equal to the final amplitude of the response current of the reverse excitation voltage; the second constraint condition is: the product of the value of the differential of the response current of the combined step excitation voltage at any moment within the delay time and the internal delay time is equal to the sum of the amplitude of the response current of the forward step excitation voltage and the amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time.

11. The system according to claim 10, wherein, The parameter determination module obtains the first parameter and the second parameter of the differential controller based on the first constraint condition and the second constraint condition, including: Based on the second constraint condition, the first parameter is obtained; Based on the first constraint condition, the proportional relationship between the first parameter and the second parameter is obtained; Based on the proportional relationship between the first parameter and the second parameter and the first parameter, the second parameter is obtained.

12. The system according to claim 10, wherein, Any moment within the delay time is the moment where the internal delay time is located.

13. The system according to claim 12, wherein, When any moment within the delay time is the moment where the internal delay time is located, the value of the differential of the response current of the combined step excitation voltage at any moment within the delay time is calculated by the following calculation formula: Wherein, l2 represents the value of the differential of the response current of the combined step excitation voltage at the internal delay time of the delay, and i 1ref (t) represents the reference current of the energy storage converter, K1 represents the first parameter of the differential controller, L represents the filter inductance and parasitic resistance on the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, and ΔT represents the internal delay time.

14. The system according to claim 13, wherein, The first parameter and the second parameter are calculated by the following calculation formula: Wherein, K1 represents the first parameter of the differential controller, K2 represents the second parameter of the differential controller, ΔT represents the internal delay time, L represents the filter inductance and parasitic resistance on the AC side of the energy storage converter, and R represents the parasitic resistance of the energy storage converter.

15. The system according to claim 9, wherein, The amplitude of the response current of the forward step excitation voltage is calculated by the following calculation formula: where, i 1ref (t) represents the reference current of the energy storage converter, K1 represents the first parameter of the differential controller, L represents the filter inductance and parasitic resistance on the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, i L1 (t) represents the amplitude of the response current of the positive step excitation voltage at time t.

16. The system according to claim 9, wherein, The amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time is calculated by the following calculation formula: Where, i L2 (t - ΔT) represents the amplitude of the response current of the reverse step excitation voltage after delaying the internal delay time, ΔT represents the internal delay time, K2 represents the second parameter of the differential controller, L represents the filter inductance and parasitic resistance on the AC side of the energy storage converter, R represents the parasitic resistance of the energy storage converter, and i 1ref (t - ΔT) represents the reference current of the energy storage converter after delaying the internal delay time.

17. A computer device, wherein, Including: One or more processors; The processor is used to store one or more programs; When the one or more programs are executed by the one or more processors, a parameter design method for a high-dynamic-performance differential controller as described in any one of claims 1 to 8 is implemented.

18. A computer-readable storage medium, wherein, A computer program is stored thereon, and when the computer program is executed, a parameter design method for a high-dynamic-performance differential controller as described in any one of claims 1 to 8 is implemented.

Images