Maximum power control system and method for oscillating water column type wave power generation device

Abstract

The invention relates to a maximum power control system and method for an oscillating water column type wave energy power generation device. The maximum power control system for the oscillating water column type wave energy power generation device comprises a turbine-permanent magnet generator, a battery charger, a battery pack, an inverter, an adjustable load box and a main controller. The maximum power control method for the oscillating water column type wave energy power generation device comprises the specific steps that a wave energy power generation device power curve is established, a battery charger outputs electric energy to charge a battery pack according to the wave energy power generation device power curve, and a battery pack voltage state machine control algorithm is designed to adjust the resistance value of an adjustable load box. Therefore, the maximum power output of the wave power generation device is ensured.

Description

Technical Field

[0001] The present invention relates to the field of wave energy power generation systems, and particularly to a maximum power control system and method for an oscillating water column type wave energy power generation device. Background Art

[0002] Wave energy is a clean new energy with high power density, wide distribution and great potential. Wave energy power generation devices convert wave energy into mechanical energy. Currently, there are mainly types such as oscillating water column type, direct drive type, pendulum type and oscillating float type. The oscillating water column type wave energy power generation device takes a turbine - permanent magnet synchronous motor as the core. The air turbine is rigidly coupled with the generator rotor. The air turbine is acted on by wave forces to push air to generate pneumatic energy. Its structure is simple and the wave energy extraction efficiency is high.

[0003] In order to maximize the extraction of wave energy by the power generation device, a correct control strategy needs to be adopted to enable the wave energy power generation device to work in the optimal working range and output the maximum power. This is crucial for improving the utilization efficiency of ocean wave energy and the energy conversion efficiency of wave energy power generation devices, and is also a problem that needs to be solved by those skilled in the art at present. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the purpose of the present invention is to propose a maximum power control system and method for an oscillating water column type wave energy power generation device, which can enable the wave energy power generation device to work in the optimal working range and output the maximum power to solve the above problems.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A maximum power control system and method for an oscillating water column type wave energy power generation device. The oscillating water column type wave energy power generation device system includes a turbine - permanent magnet generator, a battery charger, a battery pack, an inverter, an adjustable load box, and a main controller. The turbine - permanent magnet generator is connected to the battery charger to convert the pneumatic energy in the wave energy power generation device into AC electric energy. The battery charger is connected to the battery pack to convert the AC electric energy into DC electric energy and charge it into the battery pack. The battery pack is connected to the battery charger and the inverter, and is used for storing and outputting electric energy. The inverter is connected to the battery pack to convert the DC electric energy of the battery pack into AC electric energy for supplying power to the adjustable load box. The adjustable load box is connected to the inverter, is used for consuming electric energy, and can adjust the resistance value. The main controller is used for collecting voltage and current signals in the system and controlling the resistance value of the adjustable load box.

[0007] Further, the maximum power control method for the oscillating water column type wave energy power generation device specifically includes the following steps:

[0008] Step S1: Establish a power curve of a wave energy power generation device, wherein the power curve describes the output voltage U of the turbine-permanent magnet generator in the wave energy power generation device. mo and battery charger output power P co Relationship between

[0009] Step S2: the battery charger outputs electric energy to charge the battery pack according to the power curve of the wave energy power generation device;

[0010] Step S3: Design the battery pack voltage U bat The state machine control algorithm adjusts the resistance of the adjustable load box to keep the battery pack charge in an appropriate range, ensuring the maximum power output of the wave energy power generation device.

[0011] Furthermore, the drawing of the power curve in step S1 specifically includes the following steps:

[0012] Step S11: determining three working points of the starting voltage, the rated voltage and the cut-out voltage in the power curve according to the starting voltage and the rated power of the turbine-permanent magnet generator in the oscillating water column wave energy power generation device and the maximum charging voltage of the battery pack;

[0013] Step S12: Through the motor drag test and the turbine wind tunnel test, the maximum output power value corresponding to each voltage point in the power curve from the starting voltage to the rated voltage section is measured, thereby completing the drawing of the power curve.

[0014] Furthermore, the battery charger in step S2 operates according to the power curve of the wave energy power generation device and specifically includes the following steps:

[0015] Step S21: Collecting the actual output voltage U of the turbine-permanent magnet generator mo,real The actual output power P of the battery charger co,real ,

[0016] Step S22: Compare P co,real The actual output voltage U of the turbine-permanent magnet generator in the power curve mo,real The corresponding maximum output power P of the battery charger co,max , when the actual output power of the battery charger is P co,real Less than the maximum output power P of the battery charger co,max When the turbine-PMG output current is increased, the increase is ΔI mo , if the actual output power P co,real Increase, then continue to increase by ΔI mo Increase the turbine-permanent magnet generator output current until the actual output power of the battery charger reaches P co,real Not less than the maximum output power P of the battery charger co,max ; If the actual output power P co,realIf it decreases, the decrease amount is ΔI mo Reduce the output current of the turbine - permanent magnet generator until the actual output power P of the battery charger co,real is not less than the maximum output power P of the battery charger co,max .

[0017] Furthermore, the battery pack voltage U described in step S3 bat The state - machine control algorithm specifically includes the following steps:

[0018] Step S31: Divide the battery pack voltage into n (n > 0 and is an integer) battery pack voltage intervals, which are [U bat,0 , U bat,1 , …, [U bat,k-1 , U bat,k , …, [U bat,n-1 , U bat,n (U bat,0 = U bat,min , U bat,n = U bat,max ), corresponding to n adjustable load box resistance positions;

[0019] Step S32: The main controller collects the actual voltage U of the battery pack bat,real , and determines that it is in the interval [U bat,k-1 , U bat,k (0 < k ≤ n), then adjust the adjustable load box resistance position to the k - th position.

[0020] In summary, the present invention controls the output current of the turbine - permanent magnet generator to adjust the output power of the battery charger, makes the wave energy power generation device work at the maximum power output point by tracking the power curve, and then adjusts the battery pack capacity to be in a suitable interval by controlling the adjustable load box resistance position to ensure the maximum power output of the wave energy power generation device.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention controls the output current of the turbine - permanent magnet generator to adjust the output power of the battery charger, uses the power curve of the wave energy power generation device as the tracking target value, which can ensure the stability of control; and this method is simple, has strong stability and high robustness;

[0023] 2. The present invention uses an adjustable load box to adjust the battery pack capacity, judges the battery power and power generation amount, adjusts the load resistance, avoids reducing the output power of the wave energy power generation device due to too high battery pack voltage, and always ensures that the wave energy power generation device works at the maximum power output point. Brief Description of the Drawings

[0024] Figure 1It is a schematic diagram of equipment connection for the maximum power control system of an oscillating water column type wave energy power generation device.

[0025] Figure 2 It is a principle block diagram of the maximum power control method for an oscillating water column type wave energy power generation device.

[0026] Figure 3 It is a schematic diagram of the power curve of a wave energy power generation device.

[0027] Figure 4 It is a corresponding relationship diagram between different voltage ranges of the battery pack and the resistance positions of the adjustable load box. Specific implementation mode

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0029] Embodiment

[0030] As Figure 1 shown, this embodiment provides a schematic diagram of equipment connection for the maximum power control system of an oscillating water column type wave energy power generation device. The oscillating water column type wave energy power generation device system includes a turbine - permanent magnet generator, a battery charger, a battery pack, an inverter, an adjustable load box, and a main controller; the turbine - permanent magnet generator is connected to the battery charger to convert the pneumatic energy in the wave energy power generation device into AC electric energy; the battery charger is connected to the battery pack to convert the AC electric energy into DC electric energy and charge it into the battery pack; the battery pack is connected to the battery charger and the inverter, and is used for storing and outputting electric energy; the inverter is connected to the battery pack to convert the DC electric energy of the battery pack into AC electric energy for supplying power to the adjustable load box; the adjustable load box is connected to the inverter, is used for consuming electric energy, and can adjust the resistance value; the main controller is used for collecting voltage and current signals in the system and controlling the resistance value of the adjustable load box.

[0031] As Figure 2 shown, this embodiment gives a principle block diagram of the maximum power control method for an oscillating water column type wave energy power generation device, which specifically includes the following steps:

[0032] Step S1: Establish a power curve of the wave energy power generation device, and the power curve describes the relationship between the output voltage U mo of the turbine - permanent magnet generator in the wave energy power generation device and the output power P co of the battery charger.

[0033] Step S2: the battery charger outputs electric energy to charge the battery pack according to the power curve of the wave energy power generation device;

[0034] Step S3: Design the battery pack voltage U bat The state machine control algorithm adjusts the resistance of the adjustable load box to keep the battery pack charge in an appropriate range, ensuring the maximum power output of the wave energy power generation device.

[0035] In this embodiment, drawing the power curve in step S1 specifically includes the following steps:

[0036] Step S11: determining three working points of the starting voltage, the rated voltage and the cut-out voltage in the power curve according to the starting voltage and the rated power of the turbine-permanent magnet generator in the oscillating water column wave energy power generation device and the maximum charging voltage of the battery pack;

[0037] Step S12: Through the motor drag test and the turbine wind tunnel test, the maximum output power value corresponding to each voltage point in the power curve from the starting voltage to the rated voltage section is measured, so as to complete the drawing of the power curve, such as Figure 3 As shown, this embodiment provides a schematic diagram of the power curve of the wave energy power generation device;

[0038] In this embodiment, the battery charger described in step S2 operates according to the power curve of the wave energy power generation device and specifically includes the following steps:

[0039] Step S21: Collecting the actual output voltage U of the turbine-permanent magnet generator mo,real The actual output power P of the battery charger co,real ,

[0040] Step S22: Compare the actual output power P of the battery charger co,real U in the power curve mo Equal to the actual output voltage U of the turbine-permanent magnet generator mo,real The corresponding maximum output power P of the battery charger co,max , when the actual output power of the battery charger is P co,real Less than the maximum output power P of the battery charger co,max When the turbine-PMG output current is increased, the increase is ΔI mo , if the actual output power P co,real Increase, then continue to increase by ΔI mo Increase the turbine-permanent magnet generator output current until the actual output power of the battery charger reaches P co,real Not less than the maximum output power P of the battery charger co,max ; If the actual output power P co,real If it decreases, the decrease is ΔI moReduce the output current of the turbine-permanent magnet generator until the actual output power P of the battery charger co,real is not less than the maximum output power P of the battery charger co,max .

[0041] In this embodiment, the battery pack voltage U described in step S3 bat The state machine control algorithm specifically includes the following steps:

[0042] Step S31: Divide the battery pack voltage into 10 battery pack voltage intervals, namely [U bat,0 , U bat,1 , …, [U bat,k-1 , U bat,k , …, [U bat,9 , U bat,10 (U bat,0 = U bat,min , U bat,10 = U bat,max ), corresponding to 10 adjustable load box resistance value positions. As shown in Figure 4 , this embodiment gives the corresponding relationship diagram between different voltage intervals of the battery pack and the adjustable load box resistance value positions;

[0043] Step S32: The main controller collects the actual voltage U of the battery pack bat,real , and determines that it is in the interval [U bat,k-1 , U bat,k (0 < k ≤ n), then adjust the adjustable load box resistance value position to the kth position.

[0044] The above uses the control of the output current of the turbine-permanent magnet generator to adjust the output power of the battery charger, and makes the wave energy power generation device work at the maximum power output point by tracking the power curve. Then, by controlling the adjustable load box resistance value position, the battery pack capacity is adjusted to be in a suitable interval to ensure the maximum power output of the wave energy power generation device.

[0045] Preferably, this embodiment uses the control of the output current of the turbine-permanent magnet generator to adjust the output power of the battery charger, which is simple, stable, and has high robustness; this embodiment uses an adjustable load box to adjust the battery pack capacity, avoiding the reduction of the output power of the wave energy power generation device due to too high battery pack voltage, and ensuring that the device always works at the maximum power output point.

[0046] The above-described embodiments only represent the specific embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A maximum power control method for an oscillating water column type wave energy power generation device, characterized in that, Specifically, it includes the following steps: Step S1: Establish a power curve of the wave energy power generation device, where the power curve describes the relationship between the output voltage U of the turbine-permanent magnet generator in the wave energy power generation device mo and the output power P of the battery charger co therebetween; Step S2: The battery charger outputs electric energy to charge the battery pack according to the power curve of the wave energy power generation device; Step S3: Design the battery pack voltage U bat The state machine control algorithm adjusts the resistance value of the adjustable load box to keep the battery pack power within a suitable range and ensure the maximum power output of the wave energy power generation device.

2. The maximum power control method of the oscillating water column type wave energy power generation device according to claim 1, characterized in that, The drawing of the power curve in Step S1 specifically includes the following steps: Step S11: Determine three working points of the start-up voltage, rated voltage, and cut-out voltage in the power curve according to the start-up voltage, rated power of the turbine-permanent magnet generator in the oscillating water column wave energy power generation device, and the maximum charging voltage of the battery pack; Step S12: Through the motor back-to-back test and the turbine wind tunnel test, measure the maximum output power values corresponding to each voltage point between the start-up voltage and the rated voltage in the power curve, thereby completing the drawing of the power curve.

3. The maximum power control method of the oscillating water column type wave energy power generation device according to claim 1, characterized in that The battery charger in Step S2 works according to the power curve of the wave energy power generation device, specifically including the following steps: Step S21: Collect the actual output voltage U of the turbine-permanent magnet generator mo,real and the actual output power P of the battery charger co,real ; Step S22: Compare the actual output power P of the battery charger co,real The actual output voltage U of the turbine-permanent magnet generator in the power curve mo,real The corresponding maximum output power P of the battery charger co,max , when the actual output power of the battery charger is P co,real Less than the maximum output power P of the battery charger co,max When the turbine-PMG output current is increased, the increase is ΔI mo , if the actual output power P co,real Increase, then continue to increase by ΔI mo Increase the turbine-PMG output current until the actual output power P co,real Not less than the maximum output power P of the battery charger co,max ; If the actual output power P co,real If it decreases, the decrease is ΔI mo Reduce the turbine-PMG output current until the actual output power P co,real Not less than the maximum output power P of the battery charger co,max .

4. The maximum power control method of the oscillating water column type wave energy power generation device according to claim 1, characterized in that The battery pack voltage U described in step S3 bat The state machine control algorithm specifically includes the following steps: Step S31: Divide the battery pack voltage into n battery pack voltage intervals, where n is a positive integer, namely [U bat,0 , U bat,1 , …, [U bat,k-1 , U bat,k , …, [U bat,n-1 , U bat,n , where U bat,0 = U bat,min , U bat,n = U bat,max , corresponding to n adjustable load box resistance positions; Step S32: The main controller collects the actual voltage U of the battery pack bat,real , and determines that it is within the interval [U bat,k-1 , U bat,k , then adjusts the resistance gear of the adjustable load box to the k-th gear, where 0 < k ≤ n.

5. A maximum power control system for an oscillating water column type wave energy power generation device, characterized in that, For implementing the maximum power control method of the oscillating water column wave energy power generation device according to any one of claims 1-4, the maximum power control system of the oscillating water column wave energy power generation device includes a turbine-permanent magnet generator, a battery charger, a battery pack, an inverter, an adjustable load box, and a main controller; the turbine-permanent magnet generator is connected to the battery charger to convert the pneumatic energy in the wave energy power generation device into AC electric energy; the battery charger is connected to the battery pack to convert the AC electric energy into DC electric energy and charge it into the battery pack; The battery pack is connected to the battery charger and the inverter, and is used for storing and outputting electric energy; the inverter is connected to the battery pack to convert the DC electric energy of the battery pack into AC electric energy for supplying power to the adjustable load box; the adjustable load box is connected to the inverter, and is used for consuming electric energy and can adjust the resistance value; the main controller is used for collecting voltage and current signals in the system and controlling the resistance value of the adjustable load box.

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