Wave energy independent power generation system storage coordination control method based on determination rule

Abstract

This invention relates to a rule-based coordinated control method for wave energy independent power generation, storage, and utilization in a wave energy independent power generation system. It is applicable to the fields of wave energy power generation and electrochemical energy storage. The technical solution adopted in this invention is: a rule-based coordinated control method for wave energy independent power generation, storage, and utilization in a wave energy independent power generation system, characterized in that: the wave energy independent power generation system includes a power generation unit, an energy storage unit, an energy consumption unit, and a system coordination controller; the power generation unit includes a power generation branch, a power consumption branch, and a power generation unit controller; the energy storage unit includes an energy storage branch and an energy storage unit controller; the energy consumption unit includes a non-self-consumption AC / DC load branch and a load controller; the power generation branch of the power generation unit is connected to the power consumption branch, the energy storage branch, and the non-self-consumption AC / DC load branch via a DC bus.

Description

Technical Field

[0001] This invention relates to a coordinated control method for wave energy generation, storage, and utilization in an independent wave energy power generation system based on deterministic rules. It is applicable to the fields of wave energy power generation and electrochemical energy storage. Background Technology

[0002] Providing electricity generated by wave energy power generation devices to local loads (such as marine observation and communication equipment, mariculture, and marine ranches) can help reduce the cost of offshore power transmission of wave energy power generation, improve economic efficiency, and at the same time realize "ocean power for marine use", thus accelerating the development of marine industries.

[0003] Small-scale power systems composed of wave energy generation devices and local loads are divided into two categories: independent wave energy generation systems and hybrid microgrids that combine wave energy generation with photovoltaic and wind power. This invention focuses on the relatively simple topological structure of independent wave energy generation systems. Since wave energy, like solar and wind energy, is an unstable renewable energy source, it requires energy storage technology to smooth the power output while performing maximum power point tracking (PTO) to provide stable power to the load. Similar to photovoltaic and wind power, energy storage units can be added to the DC bus at the output of the wave energy generation device. This smooths the power output and avoids the negative impact of adding energy storage elements to the PTO on the device's maximum power point tracking response speed. Therefore, an independent wave energy generation system generally consists of a generation unit (i.e., the wave energy generation device), a DC bus, an energy storage unit, a load, and a series of power electronic components.

[0004] Research on power control technology for independent wave energy generation systems is limited. The dissertation "Research on Stability and Control Strategy of Hydraulic Wave Energy Generation Device" (Jinan: Shandong University, 2018) focuses on a point-absorbing independent wave energy generation system based on a hydraulic PTO. It ensures the stability of power output by implementing adaptive droop control on the power generation unit, but does not implement effective power control for the energy storage unit. The dissertation "Design and test of a new droop control algorithm for a SMES / battery hybrid energy storage system" (Energy, 2017, Vol. 118, pp. 1110-1122) focuses on a direct-drive motor type independent wave energy generation system. It uses a hybrid energy storage system composed of a superconducting magnetic energy storage system and a battery to eliminate DC bus power fluctuations and achieves power distribution among the energy storage elements through droop control.

[0005] For independent wave energy generation systems, when sea conditions are moderate and the power generation of the generating unit is less than the sum of the load consumption power and the maximum charging power of the energy storage unit, maximum power point tracking (MPPT) control can be implemented to track the maximum power generation. When sea conditions are too strong and the power generation of the generating unit exceeds the load consumption power and the maximum charging power of the energy storage unit (or the energy storage unit is fully charged), power limiting operation is required to achieve power supply and demand balance while stabilizing the DC bus voltage. Furthermore, the generating unit has a rated power limit; when the instantaneous power generation exceeds the rated power, power limiting operation must be implemented at the rated power. Although combining MPPT control and power limiting operation to implement generating unit control and system coordinated control is necessary, there is currently no simple and feasible technical solution to achieve coordinated control of an independent wave energy generation system. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a coordinated control method for the generation, storage and utilization of wave energy independent power generation system based on deterministic rules, in order to address the above-mentioned problems.

[0007] The technical solution adopted in this invention is: a coordinated control method for wave energy independent power generation system based on deterministic rules, characterized in that: the wave energy independent power generation system includes a power generation unit, a power storage unit, a power consumption unit, and a system coordination controller;

[0008] The power generation unit includes a power generation branch, a power generation self-consumption branch, and a power generation unit controller; the energy storage unit includes an energy storage branch and an energy storage unit controller; the power consumption unit includes a non-self-consumption AC / DC load branch and a load controller; the power generation branch of the power generation unit is connected to the power generation self-consumption branch, the energy storage branch, and the non-self-consumption AC / DC load branch via a DC bus.

[0009] The system coordination controller is used for:

[0010] The generated current signal I is collected from the output of the power generation branch of the power generation unit. G Collect the self-consumption current signal I from the self-consumption branch of the power generation unit. MASS The non-self-use current signal I is collected from the output of the non-self-use AC / DC load branch. L The charging and discharging current signal I on the bus side is collected from the branch outlet of the energy storage unit. C The battery-side charging and discharging current signal I is collected from the energy storage unit branch. bat Acquire bus voltage signal U from DC bus bus The battery voltage signal U is collected from the energy storage unit branch. bat ;

[0011] Through the battery side charging and discharging current signal I batCalculate the battery's SOC; using the bus voltage signal U bus and battery voltage signal U bat Calculate the maximum charging current I on the bus side. C_max and the maximum discharge current I on the bus side C_min ;

[0012] Based on the SOC size, and I G -I MASS -I L with I C_max I C_min The magnitude relationship is used to determine the system's operating condition, and the given power generation signal P is determined based on the operating condition. Glimit , Switch signal RT, Given non-self-consumed electrical load signal P Llimit and the given load combination signal;

[0013] The power generation unit controller is used for:

[0014] Based on the given power generation signal P from the system coordination controller Glimit Adjusting the PTO damping of the system;

[0015] The power generation unit's self-use power branch is equipped with a switch K to control the power supply to and from the branch. SM Switch K SM On / off control is based on the switching signal RT from the system coordination controller;

[0016] The load controller is used for:

[0017] The given non-self-consumed power load signal P from the system coordination controller Llimit Given a load combination signal, the system controls the switching of each sub-branch on the non-self-consumed AC / DC load branch according to the given load combination signal, so that the real-time non-self-consumed load equals P. Llimit ;

[0018] The energy storage unit controller is used for:

[0019] Based on bus voltage signal U bus and battery-side charging and discharging current signal I bat Control the bidirectional DC / DC converter on the energy storage unit branch.

[0020] The charging and discharging current signal I on the battery side bat Calculating the battery's SOC includes:

[0021]

[0022] Where SOC0 is the initial state of charge of the battery, C N For the rated capacity of the battery, ηC For Coulomb efficiency.

[0023] The bus voltage signal U bus and battery voltage signal U bat Calculate the maximum charging current I on the bus side. C_max and the maximum discharge current I on the bus side C_min ,include:

[0024]

[0025] Among them, I bat_max This is the maximum charging current on the battery side; I bat_min This is the maximum discharge current on the battery side.

[0026] The statement is based on the SOC size and I G -I MASS -I L with I C_max I C_min The magnitude relationship is used to determine the system's operating condition, and the given power generation signal P is determined based on the operating condition. Glimit , Switch signal RT, Given non-self-consumed electrical load signal P Llimit And a given load combination signal, including:

[0027] Under the constraint of maximum charge and discharge current, set the upper limit of SOC. max SOC median SOC mid and SOC lower limit SOC min ;

[0028] I. When SOC ≥ SOC max At this time, the battery is in full charge mode, the generator unit is in power-limited operation mode, supplying power only to the load, and the load is in set load operation mode, but the total power consumption must not exceed the battery's maximum discharge power, i.e.

[0029]

[0030] Among them, P L_set To set up non-self-use electrical loads;

[0031] II. When SOC mid ≤SOC<SOC max And I G -I MASS -I L ≥I C_max At this time, the battery is in fully charged mode, the generator unit is in power-limited operation mode, supplying power to the load and the battery, and the load is in set load operation mode, i.e.

[0032]

[0033] III. When SOC mid ≤SOC<SOC max And I G -I MASS -I L <I C_min At this time, the battery is in full-charge mode, the generator unit is in MPPT mode, the power generation is limited to the rated power, and the load is in reduced-load operation mode until the base load is reached.

[0034]

[0035] Among them, P G_max P is the rated power of the power generation unit. L,i-1 For the non-self-consumed electrical load at the previous moment, ΔP L P represents the power consumption of any non-critical load. L_min For important non-self-use electrical loads;

[0036] IV. When SOC mid ≤SOC<SOC max And I C_min ≤I G -I MASS -I L <I C_max At this time, the battery is in fully charged mode, the generator unit is in MPPT mode, the power generation is limited to the rated power, and the load is in increasing load operation mode until the set load is reached.

[0037]

[0038] V. When SOC min ≤SOC<SOC mid And I G -I MASS -I L ≥I C_max At this time, the battery is in undercharge mode, the generator unit is in power-limited operation mode, supplying power to the base load and the battery, and the load is in base load operation mode, i.e.

[0039]

[0040] VI. When SOC min ≤SOC<SOC mid And I G -I MASS -I L <I C_max At this time, the battery is in undercharge mode, the generator unit is in MPPT mode, the power generation is limited to the rated power, and the load is in basic load operation mode, i.e.

[0041]

[0042] VII. When SOC < SOC min At this time, the battery is in full discharge mode, the generator unit is in MPPT mode, the power generation is limited to the rated power, and it is fully charging the battery, but the power generation must not exceed the battery's maximum charging power. The load is in no-load operation mode, i.e.

[0043]

[0044] The given power generation signal P from the system coordination controller Glimit The PTO damping of the regulating system includes:

[0045] Compare the given power generation signal P from the system coordinator controller. Glimit and the power generation P measured at the outlet of the power generation branch of the power generation unit G The magnitude of the value is used to determine whether power-limited operation is required, and the optimal PTO damping correction value R is calculated. PTOmax1 The PTO damping is adjusted to the optimal PTO damping correction value R via the vector control module. PTOmax1 .

[0046] The calculation of the optimal PTO damping correction value R PTOmax1 ,include:

[0047] Power generation P G and a given power generation signal P Glimit The difference is sampled and held at zero order. If it is greater than 0, the median value R of damping #1 is taken. PTO1 If the value is less than 0, then take the median value R of damping #2. PTO2 After limiting the amplitude using the saturated element, the optimal PTO damping correction value R is obtained. PTOmax1 ;

[0048] 1# Damping Intermediate Value R PTO1 The calculation formula is:

[0049] R PTO1,i =R PTOmax1,i-1 -ΔR PTO

[0050] Here, the variables with subscripts i and i-1 represent the values ​​at time i and i-1, respectively, ΔR PTO The damping increment of PTO, ΔR PTO Greater than 0;

[0051] 2# Damping Intermediate Value R PTO2 The calculation formula is:

[0052]

[0053] Optimal PTO damping correction value R PTOmax1 The calculation formula is:

[0054]

[0055] Among them, R MAX R is the upper limit of PTO damping. MIN This is the lower limit of PTO damping.

[0056] The energy storage unit controller adopts a voltage outer loop and current inner loop to realize constant bus voltage charging and discharging control.

[0057] The voltage loop PI regulator acquires the bus voltage signal U in real time. bus and the reference bus voltage signal U bus_ref Same bus voltage signal U bus The difference, after being limited by the saturation cell, is used as the reference battery-side charge / discharge current signal I. bat_ref Input current loop PI regulator;

[0058] The current loop PI regulator acquires the battery-side charging and discharging current signal I at the inductor of the bidirectional DC / DC converter in real time. bat And reference battery side charge / discharge current signal I bat_ref and battery-side charging and discharging current signal I bat The difference is calculated, and after passing through two parallel PI stages and a saturation unit, it is compared with the same sawtooth wave to generate two PWM signals. After charge / discharge judgment, they are sent to IGBT1 and IGBT2 in the bidirectional DC / DC converter for Boost discharge and Buck charging, respectively.

[0059] The beneficial effects of this invention are as follows: Based on a set of deterministic rules covering all operating conditions and the working modes of each unit, this invention enables coordinated control, achieving stable DC bus voltage and balanced power generation and consumption across all operating conditions of the independent wave energy power generation system. It is simple and reliable. This invention comprehensively examines the operating modes of the power generation unit, energy storage unit, and load. By designing a first-layer power generation unit controller, energy storage unit controller, and load controller, as well as a second-layer system coordination controller, it achieves hierarchical system control, reducing the control difficulty associated with single-layer control and improving control efficiency. The power generation unit controller of this invention achieves rapid power-limited operation through the optimal value variable distance deviation method, which is simple, reliable, and free from overshoot. The energy storage unit controller of this invention directly determines charging and discharging by referencing the positive or negative charge and discharge current on the battery side, improving the accuracy of charge and discharge switching, rapidly stabilizing the bus voltage, and preventing control divergence. Attached Figure Description

[0060] Figure 1 Mechanical structure diagram of an active resonant buoyancy pendulum wave energy power generation device

[0061] Figure 2 Electrical topology diagram of an independent wave energy power generation system based on an active resonant buoyancy pendulum wave energy power generation device.

[0062] Figure 3 The overall structural block diagram of the power generation unit's power generation branch, the power generation unit's self-use power branch, and the power generation unit's controller.

[0063] Figure 4 Internal structure block diagram of the power limiting module

[0064] Figure 5 This is a block diagram of the overall structure of the energy storage unit branch and the energy storage unit controller.

[0065] Figure 6 Internal structure block diagram of the energy storage unit controller

[0066] Figure 7 Schematic diagram of battery operating modes

[0067] Figure 8 Overall structural block diagram of non-self-use AC / DC load branches and load controllers

[0068] Figure 9 Data flow diagram for the system coordinator controller

[0069] Figure 10 Flowchart of coordinated control for wave energy generation, storage, and utilization in a rule-based independent wave energy power generation system

[0070] Figure 11 A schematic diagram showing the external dimensions of an active resonant buoyancy pendulum wave energy generator used for irregular wave simulation testing.

[0071] Figure 12 Coordinated control voltage curves for operating conditions 1 to 4

[0072] Figure 13 Coordinated control current curves for operating conditions 1 to 4

[0073] Figure 14 The coordinated control counterweight position curves for working conditions 1 to 4

[0074] Figure 15 Coordinated control power curves for operating conditions 1 to 4

[0075] Figure 16 The state-of-charge curves of the battery for coordinated control from operating conditions 1 to 4.

[0076] In the diagram, 1-three-phase AC servo motor; 2-lead screw; 3-guide rod; 4-buoyancy pendulum body; 5-internal counterweight; 6-base; 7-main shaft; 8-generator support plate; 9-three-phase AC permanent magnet synchronous generator; 10-gearbox; 11-internal gear ring-gear transmission mechanism. Detailed Implementation

[0077] This embodiment is a coordinated control method for wave energy independent power generation, storage and utilization based on deterministic rules, which is applicable to different types of wave energy power generation devices based on generator vector control.

[0078] Taking an active resonant buoyancy pendulum wave energy power generation device as an example, the mechanical structure is as follows: Figure 1 As shown, the system includes a three-phase AC servo motor 1, a lead screw 2, a guide rod 3, a buoyancy pendulum body 4, an internal counterweight 5, a base 6, a main shaft 7, a generator support plate 8, a three-phase AC permanent magnet synchronous generator 9, a gearbox 10, and an internal gear ring-gear transmission mechanism 11. The three-phase AC servo motor 1, lead screw 2, guide rod 3, and base 6 constitute the counterweight position adjustment mechanism. The lower surface of the base 6 is fixed to the inner wall of the bottom of the buoyancy pendulum body 4; the lower end of the guide rod 3 is fixed to the upper surface of the base 6; the upper end of the guide rod 3 is fixed to the housing of the three-phase AC servo motor 1; the guide rod 3 passes through the internal counterweight 5 and is assembled through a linear bearing; the lower end of the lead screw 2 is equipped with a bearing, the outer wall of which is embedded in the base 6 with an interference fit; the upper end of the lead screw 2 is fixed to the shaft of the three-phase AC servo motor 1; and the nut of the lead screw 2 is fixed to the internal counterweight 5. The three-phase AC servo motor 1 has a built-in brake device to maintain the position of the internal counterweight 5 when the three-phase AC servo motor 1 is powered off. The buoyancy pendulum 4 is V-shaped. The buoyancy pendulum 4 and the main shaft 7 are assembled by bearings. The main shaft 7 passes through the base 6 without contact. The generator support plate 8 is fixed below the main shaft 7. The internal gear ring of the internal gear ring-gear transmission mechanism 11 is fixed to the inner wall of the bottom of the buoyancy pendulum 4. The gear of the internal gear ring-gear transmission mechanism 11 and the input shaft of the gearbox 10 are connected by a key. The output shaft of the gearbox 10 and the rotating shaft of the three-phase AC permanent magnet synchronous generator 9 are connected by a coupling. The housing of the three-phase AC permanent magnet synchronous generator 9 is fixed to the generator support plate 8.

[0079] The working principle of the active resonant buoyancy pendulum wave energy power generation device is as follows: the buoyancy pendulum body 4 and the internal counterweight 5 are completely submerged in water and stand above the main shaft under the action of large buoyancy torque and small gravitational torque. When the waves act, the buoyancy pendulum body 4, the internal counterweight 5, the counterweight position adjustment mechanism and the internal gear ring of the internal gear ring-gear transmission mechanism 11 swing around the main shaft 7 under the action of the waves. The internal gear ring-gear transmission mechanism 11 further drives the three-phase AC permanent magnet synchronous generator 9 to rotate and generate electricity after being accelerated by the gearbox 10. The three-phase AC servo motor 1 drives the internal counterweight 5 to move up and down along the guide rod 3 through the lead screw 2, thereby changing the natural vibration period of the active resonant buoyancy pendulum wave energy power generation device to be equal to the characteristic period of the irregular wave spectrum, thus achieving resonance.

[0080] The electrical topology of an independent wave energy generation system based on an active resonant buoyancy pendulum wave energy generator is as follows: Figure 2 As shown, it includes a power generation unit, an energy storage unit, an energy consumption unit, and a system coordination controller. The power generation unit includes a power generation branch, a power consumption branch, and a power generation controller. The energy storage unit includes an energy storage branch and an energy storage controller. The energy consumption unit includes a non-self-consumption AC / DC load branch and a load controller. The power generation branch of the power generation unit is connected to the power consumption branch, the energy storage branch, and the non-self-consumption AC / DC load branch via a DC bus.

[0081] In this example, the three-phase AC permanent magnet synchronous generator 9 is connected to the DC bus via a three-phase PWM rectifier, forming the power generation branch of the power generation unit. The three-phase AC servo motor 1 is connected to the DC bus via a three-phase PWM inverter, forming the self-consumption power branch of the power generation unit. The battery is connected to the DC bus via a bidirectional DC / DC converter, forming the energy storage unit branch. A non-self-consumption AC / DC load branch is also connected in parallel to the DC bus. The non-self-consumption AC / DC load branch includes sub-branches 1# to (M+N)#, where sub-branches 1# to M# connect to important loads 1# to M#, and sub-branches (M+1)# to (M+N)# connect to non-important loads 1# to N#. All sub-branches are combined and connected to the DC bus. A switch K is installed on the self-consumption power branch of the power generation unit. SM Switches are also installed on all sub-branches of the non-self-use AC / DC load branch, with switch K on sub-branches 1# to M# respectively. 01 To K 0M There are switches K on sub-branches (M+1)# to (M+N)# respectively. 11 To K 1N It is used to control the total number of loads connected to the bus, thereby regulating the power consumption.

[0082] In independent wave energy generation systems, the active resonant buoyancy pendulum wave energy generator operates in two modes: Maximum Power Point Tracking (MPPT) mode and power-limited operation mode. When sea conditions are moderate, the power generation does not exceed the battery's maximum charging power, and the battery is not fully charged, the RIPWEC operates in MPPT mode. When sea conditions are too rough, the RIPWEC's power generation exceeds the battery's maximum charging power, or the battery is fully charged, power-limited operation is adopted. Additionally, the RIPWEC itself has a rated power limit; when the RIPWEC's instantaneous power generation exceeds its rated power, it operates at its rated power.

[0083] like Figure 3 As shown, the power generation unit controller in this example includes a multi-timescale integrated query module, a power limiting module, a vector control module, and a servo control module. The multi-timescale integrated query module is a maximum power point tracking (PTO) algorithm module suitable for active resonant buoyancy pendulum wave energy power generation devices. It includes a resonance position table query unit based on Fast Fourier Transform (FFT) and filtering, and an optimal damping table query unit based on single-wave or multi-wave characteristics. The control process of the power generation unit controller is divided into two independent control flows. Flow 1 adaptively and dynamically adjusts the counterweight position to the resonance position corresponding to the characteristic period of the irregular wave spectrum based on the wave height signal and by querying the resonance position table, achieving resonance. Flow 2 adaptively and dynamically adjusts the PTO damping to the optimal PTO damping corresponding to the wave period and wave height of a single wave or the statistical period and statistical wave height of multiple waves based on the wave height and by querying the optimal PTO damping table, achieving maximum power point tracking while simultaneously using the power limiting module to limit the power generation to a given value.

[0084] In this embodiment, the resonance position X of a certain incident wave period max "X" refers to the position of the internal counterweight 5 when the natural oscillation period of the active resonant buoyancy pendulum wave energy generator is equal to the period of a certain incident wave, i.e., under resonant conditions. The incident wave period can refer to the period of a regular wave or the characteristic period of an irregular wave spectrum. The counterweight position X refers to the vertical distance of the internal counterweight 5 relative to its lowest position. The characteristic period can be taken as the energy period.

[0085] In this example, the resonance position table refers to the incident wave period and corresponding resonance position X that can be covered within the adjustable range of the counterweight position X of the internal counterweight 5. max The resulting relationship table can be obtained through free decaying oscillation tests in still water or forced oscillation tests in regular waves. In practical applications, the resonance position table should cover the characteristic period range of irregular wave sea states with an occurrence frequency of more than 90% in the sea area where the active resonant buoyancy pendulum wave energy power generation device is deployed.

[0086] In this embodiment, a single wave refers to the time-domain waveform formed by the wave height signals between two adjacent zero-crossing points. A multi-wave refers to the time-domain waveform formed by a sequence of adjacent single waves, that is, the time-domain waveform formed by the wave height signals between two non-adjacent zero-crossing points.

[0087] In this example, the optimal PTO damping R PTOmax This refers to resonance and PTO torque M PTO Under the condition of linear damping torque, the power PTO is P PTO When the PTO damping reaches its maximum value, the power generation P G The maximum value can also be obtained. For the same active resonant buoyancy pendulum wave energy generation device, the optimal PTO damping R under different wave periods and wave heights... PTOmax Different. PTO torque M PTO The generator torque M of the three-phase AC permanent magnet synchronous generator 9 g The resistance torque generated by the buoyancy pendulum body 4 is transmitted in the opposite direction through the gearbox 10 and the internal gear ring-gear mechanism 11.

[0088] In this embodiment, the optimal damping table is based on the wave period and wave height of different combinations of regular wave fingers and their corresponding optimal PTO damping R. PTOmax The resulting relationship table can be obtained through regular wave power testing. In practical applications, the optimal damping table should cover the range of wave periods and wave heights of single waves that occur more than 90% of the time in the sea area where the active resonant buoyancy pendulum wave energy power generation device is deployed.

[0089] In this embodiment, the specific implementation process of process 1 is as follows: the resonance position table query unit based on FFT and filtering performs FFT transformation on the wave height signal from the real-time wave height data acquisition module to obtain the irregular wave spectrum of the incident wave, filters the irregular wave spectrum, calculates the characteristic period of the filtered irregular wave spectrum, and queries the resonance position table to obtain the resonance position X corresponding to the characteristic period. max And input it into the servo control module. The servo control module will input the resonance position X. max The signal is converted into a reference position signal (i.e., a reference motor angular displacement signal) and input into the position loop PID controller inside the servo control module. The servo control module acquires the position signal (i.e., the motor angular displacement signal), speed signal (i.e., the motor angular velocity signal), and current signal of the three-phase AC servo motor 1. From the outside in, it uses a position loop PID controller, a speed loop PID controller, and a current loop PI controller to achieve closed-loop control of position, speed, and current, thereby adjusting the motor angular displacement and indirectly adjusting the counterweight position X of the internal counterweight 5 to the resonant position X. max In addition, the switching signal RT from the system coordination controller acts on switch K. SMThe power supply to the three-phase AC servo motor 1 is controlled. When RT=0, the power is cut off, the brake device is activated, the servo control module is disabled, and the counterweight position remains unchanged. When RT=1, the power is turned on, the brake device is released, and the servo control module operates normally.

[0090] In this embodiment, the specific implementation process of process 2 is as follows: the optimal damping table query unit based on single wave or multiple waves queries the optimal damping table based on the wave height signal from the real-time wave height data acquisition module, using the wave period and wave height of the previous single wave or the statistical period and statistical wave height of the previous multiple waves, to obtain the optimal PTO damping R acting on the current single wave or current multiple waves. PTOmax The input is then fed into the power limiting module. The power limiting module compares the given generator power signal P from the system coordinator with the input signal P. Glimit and the power generation P measured at the outlet of the power generation branch of the power generation unit G The magnitude of the value is used to determine whether power-limited operation is required, and the optimal PTO damping correction value R is calculated. PTOmax1 The vector control module will then assign the optimal PTO damping correction value R. PTOmax1 Converted to reference q-axis current signal The current loop PI regulator inside the vector control module is input, and the current loop PI regulator uses zero d-axis current control. The vector control module acquires the speed signal (i.e., generator angular velocity ω) of the three-phase AC permanent magnet synchronous generator 9. m1 The generator uses both signal (current signal) and current signal to achieve closed-loop current control through a current loop PI regulator, thereby regulating the generator torque M. g This indirectly changes the PTO torque M acting on the buoyancy pendulum 4. PTO To achieve PTO damping R PTO To the optimal PTO damping correction value R PTOmax1 Adjustment. Optimal PTO damping correction value R PTOmax1 and reference q-axis current signal The conversion formula is:

[0091]

[0092] Among them, K R This is the proportionality coefficient between the change in q-axis current and the change in PTO damping. ω m1 n is the generator angular velocity. p1 φ is the number of pole pairs of the generator. f1 For the magnetic flux of the permanent magnet in the generator, k g This is the transmission ratio from the buoyancy pendulum to the generator shaft.

[0093] The structure of the power limiting module in this example is as follows: Figure 4 As shown. Power generation P Gand a given power generation signal P Glimit The difference is sampled and held at zero order. If it is greater than 0, the median value R of damping #1 is taken. PTO1 If the value is less than 0, then take the median value R of damping #2. PTO2 After limiting the amplitude using the saturated element, the optimal PTO damping correction value R is obtained. PTOmax1 #1 Damping Intermediate Value R PTO1 The calculation formula is:

[0094] R PTO1,i =R PTOmax1,i-1 -ΔR PTO (2)

[0095] Here, the variables with subscripts i and i-1 represent the values ​​at time i and i-1, respectively, ΔR PTO The damping increment of PTO, ΔR PTO Greater than 0.2# Damping median value R PTO2 The calculation formula is:

[0096]

[0097] Optimal PTO damping correction value R PTOmax1 The calculation formula is:

[0098]

[0099] Among them, R MAX R is the upper limit of PTO damping. MIN This is the lower limit of PTO damping.

[0100] The structure of the energy storage unit branch and the energy storage unit controller is as follows: Figure 5 and Figure 6 As shown, constant bus voltage charging and discharging control is achieved using an outer voltage loop and an inner current loop. The voltage loop PI regulator acquires the bus voltage signal U in real time. bus and the reference bus voltage signal U bus_ref Same bus voltage signal U bus The difference, after being limited by the saturation cell, is used as the reference battery-side charge / discharge current signal I. bat_ref Input current loop PI regulator. The current loop PI regulator acquires the battery-side charging and discharging current signal I at the inductor of the bidirectional DC / DC converter in real time. bat And reference battery side charge / discharge current signal I bat_ref and battery-side charging and discharging current signal I batThe signal is differentially processed, passing through two parallel PI stages and a saturation unit, and then compared with the same sawtooth wave to generate two PWM signals. After charge / discharge determination, these signals are sent to IGBT1 and IGBT2 respectively for Boost discharge and Buck charging. The charge / discharge determination is based on the battery-side charge / discharge current signal I0. bat_ref The positive and negative properties of I bat_ref Positive values ​​trigger Buck charging, while negative values ​​trigger Boost discharging. The maximum charge / discharge current limit on the battery side is set in the saturation unit of the voltage loop PI regulator, with the maximum battery-side charging current I... bat_max Set as the maximum value of the saturated cell, the maximum discharge current I on the battery side. bat_min This is the minimum value of the saturated unit.

[0101] Batteries need to have their operating modes rationally planned based on changes in State of Charge (SOC) to prevent overcharging and over-discharging, thereby extending their lifespan. Figure 7 As shown, under the constraint of maximum charge and discharge current, the upper limit of SOC is set. max SOC median SOC mid and SOC lower limit SOC min It is divided into four operating modes: fully charged, fully charged, undercharged, and fully discharged. The maximum charging current I on the bus side... C_max and the maximum discharge current I on the bus side C_min The expression is:

[0102]

[0103] Among them, U bat This refers to the battery voltage.

[0104] When SOC is greater than the upper limit SOC max When the battery is in full charge mode, it can only discharge and will not recharge. This applies when the State of Charge (SOC) is below the lower limit. min At this time, the battery is in a fully discharged mode, meaning it can only be charged and not discharged. Simultaneously, considering that the primary function of the battery is to supply power to the base load, it can only supply power to other loads when there is a surplus of charge. Therefore, an intermediate SOC value is set between the upper and lower limits. mid When SOC is in SOC mid and SOC max During this period, the battery is in full-charge mode, with sufficient charge to supply power to the set load. When the SOC is at its maximum, the battery is in full-charge mode. min and SOC mid During this period, the battery is in undercharge mode, with insufficient power, and can only supply power to the basic load.

[0105] In this embodiment, load refers to the power consumption of the load. Load includes self-consumed load and non-self-consumed load. Self-consumed load refers to the power consumption of the three-phase AC servo motor 1, and non-self-consumed load refers to the power consumption of the non-self-consumed AC / DC load branches. In this example, the basic load refers to the total power consumption of the important loads 1# to M# and the three-phase AC servo motor 1. The basic load includes self-consumed load and important non-self-consumed load. Important non-self-consumed load refers to the power consumption of the important loads 1# to M#. The set load refers to the total power consumption of any combination of non-important loads 1# to N# added as needed, based on the important loads 1# to M# and the three-phase AC servo motor 1. The set load includes self-consumed load and set non-self-consumed load. Set non-self-consumed load refers to the total power consumption of any combination of important loads 1# to M# and the required non-important loads 1# to N#.

[0106] The structure of the non-self-use AC / DC load branch and load controller is as follows: Figure 8 As shown, the load controller receives a given non-self-consumed power load signal P from the system coordination controller. Llimit Given a load combination signal, the system controls the switching of each sub-branch on the non-self-consumed AC / DC load branch according to the given load combination signal, so that the real-time non-self-consumed load equals P. Llimit .

[0107] A given load combination signal refers to a signal that satisfies the condition that the total power consumption equals P. Llimit A group of non-self-use AC / DC load combinations, for example, combination 1: {1# to M# critical loads}, where P Llimit It should equal the important non-self-use electrical loads, combination 2: {important loads from 1# to M#, non-important load 1#, non-important load 3#}, at this time P Llimit It should be equal to the set non-self-use electrical load corresponding to combination 2.

[0108] To ensure the reliability of the power supply to the base load, the base load is only powered off in the fully discharged battery mode; power is maintained in all other situations. Considering the balance between the load's power consumption and the power supplied by the independent wave energy generation system, the load's power consumption process can be divided into five operating modes: set load operation, load reduction operation, load increase operation, base load operation, and no-load operation. When the battery has sufficient charge (i.e., the battery is fully charged or in full-charge mode) and the load is less than the sum of the battery's maximum discharge power and power generation, load increase operation is implemented until the load reaches the set load, at which point it operates at the set load. When the battery has sufficient charge but the load exceeds the sum of the battery's maximum discharge power and power generation, load reduction operation is implemented until the load drops to the base load, at which point it operates at the base load. When the battery is in undercharge mode, it operates according to the base load, and non-critical loads 1 through N are powered off. When the battery is in fully discharged mode, it operates without load, and all loads are powered off.

[0109] Data flow of the system coordinator controller, such as Figure 9 As shown, since the bus voltage can be considered constant, the power of each branch can be determined by substituting the current magnitude at the outlet of each branch on the DC bus. Therefore, the system coordinating controller collects the generator current signal I from the outlet of the generator branch of the generator unit. G Collect the self-consumption current signal I from the self-consumption branch of the power generation unit. MASS The non-self-use current signal I is collected from the output of the non-self-use AC / DC load branch. L The charging and discharging current signal I on the bus side is collected from the branch outlet of the energy storage unit. C The battery-side charging and discharging current signal I is acquired from the inductor of the bidirectional DC / DC converter. bat Acquire bus voltage signal U from DC bus bus The battery voltage signal U is collected from the battery outlet. bat Through internal calculations, a given power generation signal P is sent out. Glimit The power limiting module of the power generation unit controller sends a switching signal RT to switch K. SM Send out the given non-self-use electrical load signal P Llimit The system coordinate controller sends a combined signal with the given load to the load controller. The system coordinate controller is used to: firstly, receive the battery-side charge / discharge current signal I... bat Calculate the battery's SOC; secondly, through U... bus and U bat The maximum charging current I on the bus side is calculated based on equation (5). C_max and the maximum discharge current I on the bus side C_min Then, seven possible operating conditions for an independent wave energy power generation system are identified, based on the SOC magnitude and I. G -I MASS -I L Is it greater than I? C_max or less than I C_min Determine the current operating condition; finally, implement coordinated control of generation, storage, and utilization under all operating conditions through a set of defined rules, calculate and send out P. Glimit RT, P Llimit Combined with a given load signal.

[0110] In this embodiment, SOC can be calculated using the following formula:

[0111]

[0112] Where SOC0 is the initial state of charge of the battery, C N For the rated capacity of the battery, η C For Coulomb efficiency, it is usually 1.

[0113] The specific process for coordinated control of wave energy generation, storage, and utilization in a rule-based independent power generation system is as follows: Figure 10 As shown, the operation process is divided into 7 operating conditions, based on the SOC size and I... G -I MASS -I L Is it greater than I? C_max or less than I C_min Determine the operating condition and use an appropriate calculation formula to calculate P under that condition. Glimit RT, P Llimit The signal is combined with the given load and sent out. The judgment criteria and calculation formulas for each operating condition are as follows:

[0114] 1. When SOC ≥ SOC max At this time, the system is in operating condition 1. The battery is in full charging mode, the generator unit is in power-limited operation mode, supplying power only to the load, and the load is in set load operation mode. However, the total power consumption must not exceed the battery's maximum discharge power.

[0115]

[0116] Among them, P L_set To set up non-self-use electrical loads.

[0117] 2. When SOC mid ≤SOC<SOC max And I G -I MASS -I L ≥I C_max At this time, the system is in operating condition 2. The battery is in fully charged mode, the generator unit is in power-limited operation mode, supplying power to the load and battery. The load is in set load operation mode, i.e.

[0118]

[0119] 3. When SOC mid ≤SOC<SOC max And I G -I MASS -I L <I C_min At this time, the system is in operating condition 3. The battery is in fully charged mode, the generator unit is in MPPT mode, the generator power is limited to the rated power, and the load is in reduced load operation mode until the base load is reached.

[0120]

[0121] Among them, P G_max P is the rated power of the power generation unit. L,i-1 For the non-self-consumed electrical load at the previous moment, ΔPL P represents the power consumption of any non-critical load. L_min It is an important non-self-use electrical load.

[0122] 4. When SOC mid ≤SOC<SOC max And I C_min ≤I G -I MASS -I L <I C_max At this time, the system is in operating condition 4. The battery is in fully charged mode, the generator unit is in MPPT mode, the generator power is limited to the rated power, and the load is in increasing load operation mode until the set load is reached.

[0123]

[0124] 5. When SOC min ≤SOC<SOC mid And I G -I MASS -I L ≥I C_max At this time, the system is in operating condition 5. The battery is in undercharge mode, the generator unit is in power-limited operation mode, supplying power to the base load and battery, and the load is in base load operation mode.

[0125]

[0126] 6. When SOC min ≤SOC<SOC mid And I G -I MASS -I L <I C_max At this time, the system is in operating condition 6. Under this condition, the battery is in undercharge mode, the generator unit is in MPPT mode, the generator power is limited to the rated power, and the load is in basic load operation mode.

[0127]

[0128] 7. When SOC < SOC min At this time, the system is in operating condition 7. Under this condition, the battery is in full discharge mode, the generator unit is in MPPT mode, and the power generation is limited to the rated power, fully charging the battery, but the power generation must not exceed the battery's maximum charging power. The load is in no-load operation mode.

[0129]

[0130] It should be noted that by reasonably setting the maximum charging and discharging current of the battery, so that the maximum discharge power of the battery is greater than the maximum set load and the maximum charging power is greater than the rated power of the generator unit, the occurrence of operating conditions 2, 3 and 5 can be effectively avoided, the complexity of system coordination and control can be reduced, and the reliability of load power consumption can be improved.

[0131] Irregular wave simulation tests were conducted on an independent wave energy power generation system based on an active resonant buoyancy pendulum wave energy power generation device. The external dimensions are as follows: Figure 11 As shown, its wave-facing width is 5m. Its side profile consists of two circular arcs (upper and lower) and two transition curves (left and right), exhibiting left-right symmetry. The upper arc has a radius of 4m and an arc length of π / 3, while the lower arc has a radius of 1m and an arc length of π / 3. The centers of both arcs are the rotation center R of the buoyancy pendulum 4, i.e., the center of the main axis 7, which is 6m above the water surface. The resonance position table and the optimal damping table are shown in Table 1 and Table 2, respectively.

[0132] Table 1 Resonance Location Table

[0133] Wave cycle (s) 3 3.5 4 4.5 5 5.5 6 6.5 7 <![CDATA[X max (m)]]> 0.009 0.318 0.524 0.682 0.809 0.913 1 1.071 1.131 Wave cycle (s) 7.5 8 8.5 9 9.5 10 10.5 11 <![CDATA[X max (m)]]> 1.181 1.225 1.261 1.293 1.32 1.344 1.365 1.383

[0134] Table 2 Optimal Damping Table

[0135]

[0136] The test environment consisted of three irregular waves, namely SS1 to SS3, and the wave environment parameters are shown in Table 3. The total simulation duration was set to 1500s, and the sea state change process was SS1-SS3-SS2, with each sea state lasting 500s.

[0137] Table 3 Wave Environment Parameters

[0138]

[0139] Rated power P of the power generation unit G_max Set the power to 100kW. The initial position of the counterweight is set to 1m, with the adjustment starting at 200s and continuing every 500s thereafter. The power loss during the counterweight adjustment process is set to 500W. Then, the self-consumption power P required for the internal counterweight lifting process is... MASS Approximately 5kW (lifted at a speed of 0.005m / s), the self-consumption power P required for the descent of the internal counterweight. MASS It is 500W. The ΔR of the power limiting module. PTO Set to 500 Nms. The battery uses a lithium-ion battery with a rated voltage of 240V and a rated capacity of C. N The reference bus voltage U of the energy storage unit controller is 2500Ah. bus_ref Set to 400V, maximum charging current I on the battery side bat_max Set to 500A, the maximum discharge current I on the battery side bat_minSet to -500A, meaning a maximum current of 0.2C. N Charge and discharge, SOC max Set to 90%, SOC mid Set to 40%, SOC min Set to 10%. Significant non-self-consumed electrical load P L_min Set to 5kW, ΔP L Set to 1kW, set non-self-consumed electrical load P Lset It changes every 300 seconds, with the following progression: 20kW to 80kW to 50kW to 10kW to 40kW.

[0140] At this time, the maximum discharge power of the battery is 120kW, which is greater than the maximum set load (80kW), and the maximum charging power is 120kW, which is greater than the rated power of the generator unit (100kW). Therefore, operating conditions 2, 3 and 5 will not occur during the simulation.

[0141] Taking an initial state of charge (SOC0) of 91% for the battery as an example, the voltage, current, counterweight position, power, and battery SOC curves of the wave energy independent power generation system are as follows: Figures 12 to 16 As shown in the figure, P G For power generation, P L For non-self-consumed electrical loads, P C The charging and discharging power of the battery was measured. The results showed that:

[0142] 1) With the help of the battery, the bus voltage can be maintained at 400V, and the voltage fluctuation rate is less than or equal to ±5%.

[0143] 2) For the first 550 seconds, the system is in operating condition 1. At this time, the battery SOC is greater than 90%, and it is in full charging mode. Therefore, it can only discharge and no longer recharges. The load operates according to the set load, the counterweight position is adjusted, and the generator operates according to the power limit, with the amplitude limited to the set load. The insufficient power is supplemented by the battery (see time period 250-300 seconds). After 550 seconds, the system is in operating condition 4. At this time, the battery SOC is less than 90% but greater than 40%, and it is in full-charge mode. The generator operates according to MPPT. When the power generation reaches the rated value, it is limited to the rated value. The load increases until the set load is reached, and then it operates according to the set load. The counterweight position is adjusted. When the power generation is sufficient, the generator unit not only supplies power to the set load, but also sends the excess power to the battery. When the power generation unit is insufficient, the battery discharges to make up the difference between the power generation and the power consumption.

[0144] 3) Since the total power generation is lower than the total power consumption, the battery is in a discharging state most of the time, and its SOC drops from 91% to about 89.1%. The battery continues to discharge for the first 550 seconds, so the SOC decreases monotonically. After 550 seconds, the battery is in a charging process, so the change in SOC is no longer monotonous.

[0145] In summary, the wave energy independent power generation system based on deterministic rules can achieve smooth switching between system operating conditions, and realize DC bus voltage stability and power generation and consumption balance under all operating conditions.

Claims

1. A coordinated control method for wave energy independent power generation, storage, and utilization based on deterministic rules, characterized in that: The wave energy independent power generation system includes a power generation unit, an energy storage unit, an energy consumption unit, and a system coordination controller; The power generation unit includes a power generation branch, a power generation self-consumption branch, and a power generation unit controller; the energy storage unit includes an energy storage branch and an energy storage unit controller; the power consumption unit includes a non-self-consumption AC / DC load branch and a load controller; the power generation branch of the power generation unit is connected to the power generation self-consumption branch, the energy storage branch, and the non-self-consumption AC / DC load branch via a DC bus. The system coordination controller is used for: The generated current signal I is collected from the output of the power generation branch of the power generation unit. G Collect the self-consumption current signal I from the self-consumption branch of the power generation unit. MASS The non-self-use current signal I is collected from the output of the non-self-use AC / DC load branch. L The charging and discharging current signal I on the bus side is collected from the branch outlet of the energy storage unit. C The battery-side charging and discharging current signal I is collected from the energy storage unit branch. bat Acquire bus voltage signal U from DC bus bus The battery voltage signal U is collected from the energy storage unit branch. bat ; by the battery-side charge-discharge current signal I bat calculating the SOC of the battery; by the bus voltage signal U bus and the battery voltage signal U bat calculating the bus-side maximum charging current I C_max and the bus-side maximum discharging current I C_min ; Based on the SOC size, and I G -I MASS -I L with I C_max I C_min The magnitude relationship is used to determine the system's operating condition, and the given power generation signal P is determined based on the operating condition. Glimit , Switch signal RT, Given non-self-consumed electrical load signal P Llimit and the given load combination signal; The power generation unit controller is used for: Based on the given power generation signal P from the system coordination controller Glimit Adjusting the PTO damping of the system; The power generation unit's self-use power branch is equipped with a switch K to control the power supply to and from the branch. SM Switch K SM On / off control is based on the switching signal RT from the system coordination controller; The load controller is used for: The given non-self-consumed power load signal P from the system coordination controller Llimit Given a load combination signal, the system controls the switching of each sub-branch on the non-self-consumed AC / DC load branch according to the given load combination signal, so that the real-time non-self-consumed load equals P. Llimit ; The energy storage unit controller is used for: based on the bus voltage signal U bus and the battery-side charge-discharge current signal I bat control the bidirectional DC / DC converter on the energy storage unit branch.

2. The coordinated control method for wave energy independent power generation, storage, and utilization based on deterministic rules as described in claim 1, characterized in that, The battery-side charge-discharge current signal I bat calculating the SOC of the battery, comprising: where SOC0 is the initial state of charge of the battery, C N is the rated capacity of the battery, and η C is the coulombic efficiency.

3. The method for coordinated control of wave energy generation, storage, and utilization in an independent wave energy power generation system based on deterministic rules as described in claim 1, characterized in that, The bus voltage signal U bus and battery voltage signal U bat Calculate the maximum charging current I on the bus side. C_max and the maximum discharge current I on the bus side C_min , include: Among them, I bat_max This is the maximum charging current on the battery side; I bat_min This is the maximum discharge current on the battery side.

4. The method for coordinated control of wave energy generation, storage, and utilization in an independent wave energy power generation system based on deterministic rules as described in claim 1, characterized in that, The statement is based on the SOC size and I G -I MASS -I L with I C_max I C_min The magnitude relationship is used to determine the system's operating condition, and the given power generation signal P is determined based on the operating condition. Glimit , Switch signal RT, Given non-self-consumed electrical load signal P Llimit And a given load combination signal, including: Under the maximum charge-discharge current constraint, set the upper limit of SOC SOC max , the middle value of SOC SOC mid , and the lower limit of SOC SOC min ; Ⅰ. When SOC ≥ SOC max At this time, the battery is in full charge mode, the generator unit is in power-limited operation mode, supplying power only to the load, and the load is in set load operation mode, but the total power consumption must not exceed the battery's maximum discharge power, i.e. P L_set for setting non-self-use electric load; II. When SOC mid ≤SOC<SOC max And I G -I MASS -I L ≥I C_max At this time, the battery is in fully charged mode, the generator unit is in power-limited operation mode, supplying power to the load and the battery, and the load is in set load operation mode, i.e. III. When SOC mid ≤SOC<SOC max And I G -I MASS -I L <I C_min At this time, the battery is in full-charge mode, the generator unit is in MPPT mode, the power generation is limited to the rated power, and the load is in reduced-load operation mode until the base load is reached. Among them, P G_max P is the rated power of the power generation unit. L,i-1 For the non-self-consumed electrical load at the previous moment, ΔP L P represents the power consumption of any non-critical load. L_min For important non-self-use electrical loads; IV. When SOC mid ≤SOC<SOC max And I C_min ≤I G -I MASS -I L <I C_max At this time, the battery is in fully charged mode, the generator unit is in MPPT mode, the power generation is limited to the rated power, and the load is in increasing load operation mode until the set load is reached. V. When SOC min ≤SOC<SOC mid And I G -I MASS -I L ≥I C_max At this time, the battery is in undercharge mode, the generator unit is in power-limited operation mode, supplying power to the base load and the battery, and the load is in base load operation mode, i.e. VI. When SOC min ≤SOC<SOC mid And I G -I MASS -I L <I C_max At this time, the battery is in undercharge mode, the generator unit is in MPPT mode, the power generation is limited to the rated power, and the load is in basic load operation mode, i.e. VII. When SOC < SOC min At this time, the battery is in full discharge mode, the generator unit is in MPPT mode, the power generation is limited to the rated power, and it is fully charging the battery, but the power generation must not exceed the battery's maximum charging power. The load is in no-load operation mode, i.e.

5. The method for coordinated control of wave energy generation, storage, and utilization in an independent wave energy power generation system based on deterministic rules as described in claim 1, characterized in that, The given power generation signal P Glimit Adjusting the PTO damping of a system, comprising: Compare the given power generation signal P from the system coordinator controller. Glimit and the power generation P measured at the outlet of the power generation branch of the power generation unit G The magnitude of the value is used to determine whether power-limited operation is required, and the optimal PTO damping correction value R is calculated. PTOmax1 The PTO damping is adjusted to the optimal PTO damping correction value R via the vector control module. PTOmax1 .

6. The method for coordinated control of wave energy independent power generation, storage, and utilization based on deterministic rules as described in claim 5, characterized in that, The computing the optimal PTO damping correction value R PTOmax1 comprises: Power P G And the difference of given power signal P Glimit After sampling and zero-order hold, judge whether it is greater than 0, greater than 0, take 1# damping intermediate value R PTO1 Less than 0, take 2# damping intermediate value R PTO2 After limiting by saturation unit, the optimal PTO damping correction value R PTOmax1 is obtained 1# damping intermediate value R PTO1 The calculation formula is: R PTO1,i = R PTOmax1,i-1 - ΔR PTO where the variables with subscripts i and i-1 represent the values at the i and i-1 instants, respectively, ΔR PTO denotes the PTO damping increment, ΔR PTO is greater than 0; 2# damping intermediate value R PTO2 The calculation formula is: optimal PTO damping correction value R PTOmax1 The calculation formula is: where R MAX is the PTO damping upper limit, R MIN is the PTO damping lower limit.

7. The method for coordinated control of wave energy generation, storage, and utilization in an independent wave energy power generation system based on deterministic rules as described in claim 1, characterized in that: The energy storage unit controller adopts a voltage outer loop and current inner loop to realize constant bus voltage charging and discharging control. The voltage loop PI regulator acquires the bus voltage signal U in real time. bus and the reference bus voltage signal U bus_ref Same bus voltage signal U bus The difference, after being limited by the saturation cell, is used as the reference battery-side charge / discharge current signal I. bat_ref Input current loop PI regulator; The current loop PI regulator acquires the battery-side charging and discharging current signal I at the inductor of the bidirectional DC / DC converter in real time. bat And reference battery side charge / discharge current signal I bat_ref and battery-side charging and discharging current signal I bat The difference is calculated, and after passing through two parallel PI stages and a saturation unit, it is compared with the same sawtooth wave to generate two PWM signals. After charge / discharge judgment, they are sent to IGBT1 and IGBT2 in the bidirectional DC / DC converter for Boost discharge and Buck charging, respectively.

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