Fire and energy storage combined frequency modulation control method based on cooperation of super capacitor and energy storage battery

Abstract

A fire and energy storage combined frequency modulation control method based on cooperation of a super capacitor and an energy storage battery comprises the steps that 1, a power grid AGC frequency modulation instruction is received, and the instruction type, the target power change absolute value Pref and the instruction duration T are analyzed; 2, collecting the state of charge (SOC) of the super capacitor and the energy storage battery; 3, dividing into three power change rate regions according to the instruction, and constraining the output cooperative control of the super capacitor and the energy storage battery in different power change rate regions; and 4, executing frequency modulation work and feeding back the SOC state of the energy storage system. Through staged cooperative control of the super capacitor and the energy storage battery, the frequency modulation response speed and the capacity precision are considered, compared with a traditional super capacitor-energy storage battery combined frequency modulation strategy, a frequency modulation instruction analysis and SOC constraint judgment mechanism is introduced, power and output cooperation between the super capacitor and the energy storage battery in the frequency modulation process is dynamically adjusted, and the frequency modulation efficiency is improved. And the frequency modulation implementation effect is ensured.

Description

Technical Field

[0001] This invention relates to a combined frequency regulation control method for thermal power generation and energy storage based on the collaboration of supercapacitors and energy storage batteries. Background Technology

[0002] In combined thermal power and energy storage frequency regulation systems, thermal power units exhibit slow response times (typically several seconds to minutes), making it difficult to cope with frequency fluctuations caused by the integration of a high proportion of renewable energy. Traditional energy storage systems mostly employ single-cell technologies (such as lithium batteries), which suffer from the following problems:

[0003] 1. Insufficient response speed: Due to the limited chemical reaction rate, the battery has a significant initial frequency tuning delay, which can easily lead to frequency degradation.

[0004] 2. Poor frequency modulation accuracy: Although supercapacitors have a fast response, their low energy density makes them unable to maintain frequency modulation for long periods of time; batteries can provide steady-state support, but their dynamic response is slow.

[0005] 3. Lack of coordinated control: Existing strategies mostly use fixed power allocation, which cannot be dynamically adjusted according to instructions, resulting in poor frequency modulation effect.

[0006] Therefore, improved technologies have led to the synergistic control of supercapacitors (high power density, millisecond-level response, long cycle life) and energy storage batteries (high energy density, high regulation accuracy, large capacity). The core principle is to resolve the contradiction between "response speed, regulation accuracy, and equipment lifespan" in combined thermal and energy storage frequency regulation through complementary characteristics. Early static priority strategies focused on using supercapacitors to handle low-power / high-frequency fluctuations and lithium batteries to handle high-power / long-term fluctuations. For example:

[0007] When the AGC command power is less than or equal to the supercapacitor's rated power, the supercapacitor provides the full response (avoiding frequent charging and discharging of the lithium battery); when the command power exceeds the supercapacitor's rated power, the excess is compensated by the lithium battery. This strategy is simple to implement and can reduce lithium battery cycle losses, but it does not consider the dynamic effects of power change rate and energy storage SOC state. Summary of the Invention

[0008] This invention provides a combined thermal and energy storage frequency regulation control strategy based on the collaboration of supercapacitors and energy storage batteries to solve the problems of slow response speed and insufficient accuracy of traditional frequency regulation systems.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A combined frequency regulation control method for thermal power generation and energy storage based on the synergy of supercapacitors and energy storage batteries includes the following steps:

[0011] Step 1: First, receive the AGC frequency regulation command from the power grid, and parse the command type and the absolute value of the target power change P. refand the duration T of the instruction; the instruction type here is charging, discharging, or power maintenance;

[0012] Step 2: Collect the State of Charge (SOC) of the supercapacitor and energy storage battery;

[0013] Step 3: Divide the system into three power change rate zones according to the instructions, and constrain the coordinated output control of the supercapacitor and energy storage battery under different power change rate zones:

[0014] Step 4: Perform frequency modulation and feedback the SOC status of the energy storage system; after determining the target charge and discharge power of the supercapacitor and the energy storage battery, convert the target values ​​of the two into the format of "charge / discharge indicator + absolute value": discharge is positive (+) and charging is negative (-), clarifying the direction of equipment action; then send the instruction to the controller of the energy storage system to coordinate the supercapacitor controller and the battery management system to control the supercapacitor and the energy storage body to complete the charge and discharge.

[0015] Step 3 specifically involves:

[0016] (1) In the high power change rate region, |dP / dt|>k1

[0017] Coordination principle: Supercapacitors respond first, and energy storage batteries gradually rise and fall to compensate;

[0018] Supercapacitor output: P SC =min[P ref ×λ SC ,P SCmax ];

[0019] Wherein, the rate of change of reaction power, |dP / dt|, is specifically:

[0020]

[0021] k1 is the threshold for high / medium power change rate. The core of k1 is to distinguish between scenarios where supercapacitors prioritize shock absorption and scenarios where dual devices dynamically share the load.

[0022] k1=min[k SCmax ×0.8, k SBmax ×2.5];

[0023] k SCmax The maximum safe power change rate of the supercapacitor is multiplied by 0.8 to leave a safety margin.

[0024] k SBmax The maximum safe power change rate of the energy storage battery is multiplied by 2.5 to ensure that k1 is much greater than the battery's safe power change rate.

[0025] λ SC The output weight of the supercapacitor must be determined, and the SOC constraint must be met:

[0026] If SOC SC ≤SOC SC.low (Supercapacitor nearing over-discharge), forced reduction of λ SC Keep the level between 0.5 and 0.6 to avoid deep discharge;

[0027] If SOC SC SOC SC.high (The supercapacitor is close to overcharge), forcibly reducing λ. SC It ranges from 0.3 to 0.4, only subject to minor fluctuations;

[0028] Energy storage battery output: P SB = P ref -P SC ;

[0029] (2) In the region of medium power change rate, k1≥|dP / dt|>k2

[0030] A bivariate adaptive weight model is constructed based on the power change rate and SOC, with the core formula as follows:

[0031] Supercapacitor output weight λ SC :

[0032] Energy storage battery output weight λ SB =1−λ SC ;

[0033] Where k2 is the threshold for the medium / low power change rate;

[0034] K2=max[k SCidle ×1.2, k SBstable ×1.2, k AGClow ];

[0035] k SCidle The minimum power change rate to avoid ineffective cycles for supercapacitors; when the change rate is below this value, frequent operation of the supercapacitor will cause ineffective losses.

[0036] k SBstable The optimal power change rate for smooth adjustment of the energy storage battery;

[0037] k AGClow The maximum rate of change of steady-state fluctuations in AGC commands;

[0038] λ SOC,SC This is the SOC correction factor, reflecting the current output capacity of the supercapacitor;

[0039] If SOC SC ∈[30%, 70%], this is the optimal interval, and λ is at this point.SOC,SC =1;

[0040] If SOC SC ∈[10%,30%]∪[70%,90%], this is the suboptimal interval, and λ is... SOC,SC =0.7;

[0041] If SOC SC <10% or >90%, this is the critical interval, at which point λ SOC,SC =0.3;

[0042] Supercapacitor output: P SC =min[P ref ×λ SC ,P SCmax ];

[0043] Energy storage battery output: P SB =min[P ref ×λ SB ,P SBmax ];

[0044] If, under this condition, the total output is insufficient, i.e., P... SC +P SB < P ref Prioritize the output of devices with the highest SOC range, and supplement the remaining power from other sources.

[0045] (3) Low power change rate region |dP / dt|<k2

[0046] Energy storage batteries handle 90% to 100% of the total power demand, utilizing their high energy density to provide continuous power, reducing unnecessary charge and discharge cycles of supercapacitors, and extending their lifespan.

[0047] Energy storage battery output: P SB =min[P ref ×0.95, λ SOC,SB ×P SBmax ];

[0048] Where, λ SOC,SB This is the SOC correction factor, reflecting the current output capacity of the energy storage battery;

[0049] If SOC SB ∈[SOC SB.low SOC SB.high ], λ SOC,SB =1;

[0050] If SOC SB <SOC SB.low or > SOC SB.high ,λ SOC,SB=0.7, avoid deep charging and discharging;

[0051] Supercapacitor output: P SC = P ref -P SB .

[0052] The present invention, which adopts the above technical solution, balances frequency regulation response speed and capacity accuracy by implementing phased coordinated control of supercapacitors and energy storage batteries. Compared with the traditional supercapacitor-energy storage battery joint frequency regulation strategy, it introduces frequency regulation command analysis and SOC constraint judgment mechanism to dynamically adjust the power and output coordination between the two during the frequency regulation process, so as to ensure the frequency regulation implementation effect. Attached Figure Description

[0053] Figure 1 This is a flowchart of the present invention;

[0054] Figure 2 This is the electrical main wiring diagram of the present invention. Detailed Implementation

[0055] To facilitate understanding of the purpose, technical solution, and advantages of this invention by those skilled in the art, the invention will be further described in detail below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments.

[0056] A combined frequency regulation control method for thermal power generation and energy storage based on the synergy of supercapacitors and energy storage batteries includes the following steps:

[0057] Step 1: First, receive the AGC frequency regulation command from the power grid, and parse the command type and the absolute value of the target power change P. ref and the duration T of the instruction; the instruction type here is charging, discharging, or power maintenance;

[0058] Step 2: Collect the State of Charge (SOC) of the supercapacitor and energy storage battery;

[0059] Step 3: Divide the system into three power change rate zones according to the instructions, and constrain the coordinated output control of the supercapacitor and energy storage battery under different power change rate zones:

[0060] (1) In the high power change rate region, |dP / dt|>k1

[0061] Coordination principle: Supercapacitors respond first, and energy storage batteries gradually rise and fall to compensate;

[0062] Supercapacitor output: P SC =min[P ref ×λ SC ,P SCmax ];

[0063] Wherein, the rate of change of reaction power, |dP / dt|, is specifically:

[0064]

[0065] k1 is the threshold for high / medium power change rate. The core of k1 is to distinguish between scenarios where supercapacitors prioritize shock absorption and scenarios where dual devices dynamically share the load.

[0066] k1=min[k SCmax ×0.8, k SBmax ×2.5];

[0067] k SCmax The maximum safe power change rate of the supercapacitor is multiplied by 0.8 to leave a safety margin.

[0068] k SBmax The maximum safe power change rate of the energy storage battery is multiplied by 2.5 to ensure that k1 is much greater than the battery's safe power change rate.

[0069] λ SC Weighting of supercapacitor output (default λ in high fluctuation region) SC =0.9~1.0), and must satisfy the SOC constraint:

[0070] If SOC SC ≤SOC SC.low (Supercapacitor nearing over-discharge), forced reduction of λ SC Keep the level between 0.5 and 0.6 to avoid deep discharge;

[0071] If SOC SC SOC SC.high (The supercapacitor is close to overcharge), forcibly reducing λ. SC It ranges from 0.3 to 0.4, only subject to minor fluctuations;

[0072] Energy storage battery output: P SB = P ref -P SC ;

[0073] (2) In the region of medium power change rate, k1≥|dP / dt|>k2

[0074] A bivariate adaptive weight model is constructed based on the power change rate and SOC, with the core formula as follows:

[0075] Supercapacitor output weight λ SC :

[0076] Energy storage battery output weight λ SB =1−λ SC ;

[0077] Where k2 is the threshold for the medium / low power change rate;

[0078] K2=max[k SCidle ×1.2, k SBstable ×1.2, k AGClow ];

[0079] k SCidle The minimum power change rate to avoid ineffective cycles for supercapacitors; when the change rate is below this value, frequent operation of the supercapacitor will cause ineffective losses.

[0080] k SBstable The optimal power change rate for smooth adjustment of the energy storage battery;

[0081] k AGClow The maximum rate of change of steady-state fluctuations in AGC commands;

[0082] λ SOC,SC This is the SOC correction factor, reflecting the current output capacity of the supercapacitor;

[0083] If SOC SC ∈[30%, 70%], this is the optimal interval, and λ is at this point. SOC,SC =1;

[0084] If SOC SC ∈[10%,30%]∪[70%,90%], this is the suboptimal interval, and λ is... SOC,SC =0.7;

[0085] If SOC SC <10% or >90%, this is the critical interval, at which point λ SOC,SC =0.3;

[0086] Supercapacitor output: P SC =min[P ref ×λ SC ,P SCmax ];

[0087] Energy storage battery output: P SB =min[P ref ×λ SB ,P SBmax ];

[0088] If, under this condition, the total output is insufficient, i.e., P... SC +P SB < P ref Prioritize the output of devices with the highest SOC range, and supplement the remaining power from other sources.

[0089] (3) Low power change rate region |dP / dt|<k2

[0090] Energy storage batteries handle 90% to 100% of the total power demand, utilizing their high energy density to provide continuous power, reducing unnecessary charge and discharge cycles of supercapacitors, and extending their lifespan.

[0091] Energy storage battery output: P SB =min[P ref ×0.95, λ SOC,SB ×P SBmax ];

[0092] Where, λ SOC,SB This is the SOC correction factor, reflecting the current output capacity of the energy storage battery;

[0093] If SOC SB ∈[SOC SB.low SOC SB.high ], λ SOC,SB =1;

[0094] If SOC SB <SOC SB.low or > SOC SB.high ,λ SOC,SB =0.7, avoid deep charging and discharging;

[0095] Supercapacitor output: P SC = P ref -P SB ;

[0096] Step 4: Perform frequency modulation and feedback the SOC status of the energy storage system; after determining the target charge and discharge power of the supercapacitor and the energy storage battery, convert the target values ​​of the two into the format of "charge / discharge indicator + absolute value", that is: discharge is positive (+) and charging is negative (-), clarifying the direction of equipment action; then send the instruction to the controller of the energy storage system to coordinate the supercapacitor controller and the battery management system to control the supercapacitor and the energy storage body to complete the charge and discharge.

[0097] The specific connection structure is as follows: Figure 2 As shown, the power plant has two high-voltage transformers, #1 and #2. The #1 transformer is connected to the 10kV B section 71 of the energy storage system via a 10kV common busbar 3. The low-voltage side of the #2 transformer is connected to the 10kV A section 72 of the energy storage system via a 10kV common busbar 3. Both the 10kV B section 71 and the 10kV A section 72 are connected to at least one supercapacitor 8 and at least one energy storage battery 9. Each supercapacitor 8 and energy storage battery 9 is connected to the 10kV energy storage section via a zero-sequence protection circuit 4, a current transformer 5, and a vacuum circuit breaker 6, respectively.

[0098] It should be noted that during operation, the state of charge (SOC) of the supercapacitor and energy storage battery is collected through the current transformer 5.

[0099] The beneficial effects of this invention are as follows:

[0100] No hysteresis response: The supercapacitor has a millisecond-level response under high power change rate, which solves the power gap caused by the "response delay" of the energy storage battery;

[0101] (2) Long lifespan: Overcharging and over-discharging are avoided by SOC constraint, and the supercapacitors bear high-frequency fluctuations, reducing the number of cycles of the energy storage battery;

[0102] (3) Strong adaptability: The power change rate and SOC are dynamically adjusted to adapt to the full range of working conditions from "fluctuation-steady state-abrupt change", and have good prospects for promotion and application;

[0103] (4) Higher adjustment precision, solving the problem of "deviation caused by static allocation";

[0104] (5) The SOC has more safety redundancy to avoid "critical state overload".

Claims

1. A method for joint frequency regulation control of thermal power generation and energy storage based on the synergy of supercapacitors and energy storage batteries, characterized in that: It includes the following steps: Step 1: First, receive the AGC frequency regulation command from the power grid, and parse the command type and the absolute value of the target power change P. ref and the duration T of the instruction; the instruction type here is charging, discharging, or power maintenance; Step 2: Collect the State of Charge (SOC) of the supercapacitor and energy storage battery; Step 3: Divide the system into three power change rate zones according to the instructions, and constrain the coordinated output control of the supercapacitor and energy storage battery under different power change rate zones: Step 4: Perform frequency modulation and feedback the SOC status of the energy storage system; after determining the target charge and discharge power of the supercapacitor and the energy storage battery, convert the target values ​​of the two into the format of "charge / discharge indicator + absolute value": discharge is positive (+) and charging is negative (-), clarifying the direction of equipment action; then send the instruction to the controller of the energy storage system to coordinate the supercapacitor controller and the battery management system to control the supercapacitor and the energy storage body to complete the charge and discharge.

2. The method for joint frequency regulation control of thermal power generation and energy storage based on the synergy of supercapacitors and energy storage batteries according to claim 1, characterized in that: Step 3 specifically involves: (1) In the high power change rate region, |dP / dt|>k1 Coordination principle: Supercapacitors respond first, and energy storage batteries gradually rise and fall to compensate; Supercapacitor output: P SC =min[P ref ×λ SC ,P SCmax ]; Wherein, the rate of change of reaction power, |dP / dt|, is specifically: ； k1 is the threshold for high / medium power change rate. The core of k1 is to distinguish between scenarios where supercapacitors prioritize shock absorption and scenarios where dual devices dynamically share the load. k1=min[k SCmax ×0.8,k SBmax ×2.5]; k SCmax The maximum safe power change rate of the supercapacitor is multiplied by 0.8 to leave a safety margin. k SBmax The maximum safe power change rate of the energy storage battery is multiplied by 2.5 to ensure that k1 is much greater than the battery's safe power change rate. λ SC The output weight of the supercapacitor must be determined, and the SOC constraint must be met: If SOC SC ≤SOC SC.low (Supercapacitor nearing over-discharge), forced reduction of λ SC To avoid deep discharge, maintain a pH of 0.5-0.

6. If SOC SC SOC SC.high (The supercapacitor is close to overcharge), forcibly reducing λ. SC It ranges from 0.3 to 0.4, only subject to minor fluctuations; Energy storage battery output: P SB = P ref -P SC ; (2) In the region of medium power change rate, k1≥|dP / dt|>k2 A bivariate adaptive weight model is constructed based on the power change rate and SOC, with the core formula as follows: Supercapacitor output weight λ SC : ; Energy storage battery output weight λ SB =1−λ SC ; Where k2 is the threshold for the medium / low power change rate; K2=max[k SCidle ×1.2,k SBstable ×1.2,k AGClow ]; k SCidle The minimum power change rate to avoid ineffective cycles for supercapacitors; when the change rate is below this value, frequent operation of the supercapacitor will cause ineffective losses. k SBstable The optimal power change rate for smooth adjustment of the energy storage battery; k AGClow The maximum rate of change of steady-state fluctuations in AGC commands; λ SOC,SC This is the SOC correction factor, reflecting the current output capacity of the supercapacitor; If SOC SC ∈[30%, 70%], this is the optimal interval, and λ is at this point. SOC,SC =1; If SOC SC ∈[10%,30%]∪[70%,90%], this is the suboptimal interval, and λ is... SOC,SC =0.7; If SOC SC <10% or >90%, this is the critical interval, at which point λ SOC,SC =0.3; Supercapacitor output: P SC =min[P ref ×λ SC ,P SCmax ]; Energy storage battery output: P SB =min[P ref ×λ SB ,P SBmax ]; If, under this condition, the total output is insufficient, i.e., P... SC +P SB < P ref Prioritize the output of devices with the highest SOC range, and supplement the remaining power from other sources. (3) Low power change rate region |dP / dt|<k2 Energy storage batteries handle 90% to 100% of the total power demand, utilizing their high energy density to provide continuous power, reducing unnecessary charge and discharge cycles of supercapacitors, and extending their lifespan. Energy storage battery output: P SB =min[P ref ×0.95, λ SOC,SB ×P SBmax ]; Where, λ SOC,SB This is the SOC correction factor, reflecting the current output capacity of the energy storage battery; if SOC SB ∈[SOC SB.low , SOC SB.high ],λ SOC,SB =1; If SOC SB <SOC SB.low or > SOC SB.high ,λ SOC,SB =0.7, avoid deep charging and discharging; Supercapacitor output: P SC = P ref -P SB。

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