Principle of wind-solar complementary discharge control

Q wind turbine

In the energy transition, I recognize the growing importance of wind and solar energy as clean and renewable energy sources. However, their intermittency and instability have always been challenges that limit their large-scale application. Fortunately, the wind-solar complementary system has emerged, providing an effective solution to this problem. The Wind solar hybrid system discharge control technology has become the key to ensuring the efficient and stable operation of the entire system. I will delve into the principles and implementation of this control technology to reveal how it can become the “intelligent brain” of the new energy system.

1. Overview of wind-solar complementary system

Before we delve into the principle of charge and discharge control, it is necessary to understand the basic composition of the wind-solar complementary system. A typical wind-solar complementary system usually includes the following main parts:

Wind power generation unit
Photovoltaic power generation unit
Battery pack
Charge and discharge controller
Inverter
Load
Among them, the wind power generation unit and the photovoltaic power generation unit are responsible for energy collection and conversion, the battery pack is used for energy storage, and the charge and discharge controller is the core of the entire system, responsible for coordinating the work of each unit to achieve efficient use of energy. The inverter converts DC power into AC power for use by the load.

2. Wind-solar hybrid charging principle: the art of energy collection and conversion

The wind-solar hybrid charging principle is the basis for the operation of the entire system. It involves how to efficiently collect and convert wind and solar energy. The core of this principle is to make full use of the complementary characteristics of wind and solar energy to achieve all-weather, high-efficiency power generation.

2.1 Wind power charging principle

The basic principle of wind power generation is to use wind energy to drive the wind wheel to rotate and drive the generator to generate electricity. During the charging process, the wind power generation system needs to consider the following key factors:

Wind speed and power curve: The output power of the wind turbine is different at different wind speeds. The charging controller needs to adjust the charging strategy according to the real-time wind speed.

Maximum power point tracking (MPPT): By adjusting the speed or load of the wind turbine, it always works at the optimal efficiency point.

Overspeed protection: When the wind speed is too high, timely measures need to be taken to protect the wind turbine, such as variable pitch control or braking.

2.2 Photovoltaic power charging principle

Photovoltaic power generation is to directly convert solar energy into electrical energy using the photoelectric effect. The key to the photovoltaic charging system is:

Light intensity and output power: The charging controller needs to adjust the charging current according to the change of light intensity.
Maximum power point tracking (MPPT): By adjusting the working voltage of the photovoltaic panel, it always works at the maximum power point to improve the power generation efficiency.

Temperature compensation: The efficiency of the photovoltaic panel will decrease with the increase of temperature, and the controller needs to perform temperature compensation to optimize the charging effect.

2.3 Advantages of wind-solar complementary

Wind energy and solar energy have good complementarity in time and space. When the solar energy is sufficient during the day, the photovoltaic system plays a major role; at night or on cloudy days, wind energy may be more abundant. Through reasonable design, the wind-solar complementary system can significantly improve the stability and reliability of power generation, reduce the capacity demand of the battery, and reduce the system cost.

3. Wind-solar complementary discharge control unit: the core brain of the system

The charge and discharge control unit is the core of the wind-solar complementary system. It is responsible for coordinating the energy flow between wind power generation, photovoltaic power generation and batteries to ensure the efficient and stable operation of the system. Let’s discuss the charge and discharge control units of wind power generation and photovoltaic power generation respectively.

3.1 Wind power generation charge and discharge control unit

The main functions of the wind power generation charge and discharge control unit include:

Wind speed detection and power prediction: Real-time monitoring of wind speed through wind speed sensor, combined with the power curve of wind turbine, predicting possible power generation.
MPPT control: According to wind speed and generator characteristics, adjust the speed or load of the generator to make it work at the optimal efficiency point.
Charging management: Reasonably distribute the output power of wind turbine according to the status of battery and system load.
Overload protection: When the wind speed is too high, start the protection mechanism, such as pitch control or mechanical braking, to protect the wind turbine.
Grid-connected control: In the grid-connected system, the control unit also needs to coordinate the power exchange between wind power generation and the grid.

3.2 Photovoltaic array charge and discharge control unit

The main functions of the photovoltaic array charge and discharge control unit include:

Light intensity detection: Real-time monitoring of light intensity through light sensor, predicting the power generation capacity of photovoltaic array.
MPPT control: By adjusting the working voltage of photovoltaic array, it always works at the maximum power point.
Charging management: Reasonably distribute photovoltaic power according to battery status and system load.
Temperature compensation: monitor the temperature of the photovoltaic panel and perform temperature compensation to optimize the charging effect.
Anti-reverse charging: prevent the battery from discharging to the photovoltaic panel when the light is insufficient.

4. Dual-standard three-stage charging principle and implementation: the wisdom of battery management

The battery is a key component in the wind-solar hybrid system, and its charge and discharge management directly affects the performance and life of the system. Dual-standard three-stage charging is an advanced charging strategy that can effectively extend the battery life and improve the charging efficiency.

4.1 Dual-standard three-stage charging principle

Dual-standard three-stage charging includes the following three stages:

Constant current charging stage (Bulk Charging):
In this stage, the controller charges the battery with the maximum available current until the battery voltage reaches the preset absorption voltage point. This stage can quickly charge the battery to about 80% of its capacity.

Absorption charging stage (Absorption Charging):
When the battery voltage reaches the absorption voltage point, the controller will maintain this voltage while gradually reducing the charging current. This stage can charge the battery to about 95% of its capacity while avoiding overcharging.
Float Charging:
When the charging current drops to the preset value (usually 1%-3% of the rated capacity), the controller reduces the voltage to the floating charging voltage and maintains low current charging to compensate for the self-discharge of the battery.
“Dual standard” refers to two voltage standards: absorption voltage and floating charging voltage. The setting of these two voltage values ​​is crucial to the life and performance of the battery.

4.2 Implementation of dual standard three-stage charging

To achieve dual standard three-stage charging, the charge and discharge controller needs to have the following functions:

Voltage and current monitoring: real-time monitoring of the battery voltage and charging current.
Temperature compensation: adjust the charging voltage according to the ambient temperature, because the optimal charging voltage of the battery will change with temperature.
Intelligent switching: automatically switch the charging stage according to the battery status.
Adjustable parameters: allow users to adjust the charging parameters according to different types of batteries.
Balanced charging: for systems with multiple batteries in series, balanced charging function needs to be implemented to extend the life of the battery pack.

4.3 Advantages of dual-standard three-stage charging

Compared with traditional constant voltage charging or single-stage charging, dual-standard three-stage charging has the following advantages:

High charging efficiency: The constant current stage can charge quickly, and the battery can be fully charged in the absorption stage.

Extend battery life: Avoid overcharging and undercharging, and reduce battery loss.

Strong adaptability: Parameters can be adjusted according to different types of batteries, and the application range is wide.

High safety: Multiple protection mechanisms avoid dangerous situations such as overcharging and over-discharging.

5. Power control: The art of energy balance

In the wind-solar complementary system, power control is the key to ensure the stable operation of the system. It needs to coordinate the power balance between wind power generation, photovoltaic power generation, batteries and loads to achieve efficient use of energy.

5.1 Power balance strategy

The core of power control is to achieve the power balance of the system, which mainly includes the following aspects:

Power generation power control: Control the output power of wind turbines and photovoltaic arrays according to wind speed and light intensity.

Charging power control: Adjust the charging power according to the state of the battery and the system load.
Discharge power control: Control the discharge power according to the load demand and battery status.
Load management: Load shedding is performed when necessary to protect the system.

5.2 Application of MPPT technology in power control

Maximum power point tracking (MPPT) technology is an important means of power control, which can ensure that wind turbines and photovoltaic arrays always work at the best efficiency point. The MPPT controller maximizes the output power of the power generation unit by continuously adjusting the working point.

5.3 Intelligent power distribution

In the wind-solar hybrid system, the intelligent power distribution algorithm can dynamically adjust the power output of each unit according to the real-time power generation situation, load demand and battery status. For example:

When wind and solar energy are sufficient, these renewable energy sources are used to supply the load first, and the excess power is used for charging.

When renewable energy is not enough to meet the load demand, the controller will instruct the battery to discharge and supplement.

When the load demand is low and renewable energy is sufficient, the controller will limit the power generation or store the excess power in the battery.

In extreme cases, such as when the battery power is too low and the renewable energy is insufficient, the controller will execute the load shedding strategy to protect the system.

5.4 Power prediction and dispatch

Advanced wind-solar hybrid systems can also combine weather forecast data to predict power generation in the future, thereby achieving more intelligent power dispatch. This predictive dispatch can:

Plan the battery charging and discharging strategy in advance.

Optimize the load usage time and arrange high-power loads during the peak power generation period.

In the grid-connected system, reasonably arrange the power exchange with the grid.

6. Monitoring unit: the “eyes” and “ears” of the system

The monitoring unit is the “eyes” and “ears” of the wind-solar hybrid system. It monitors the operating status of the system in real time through various sensors and communication equipment, providing a basis for control decisions.

6.1 Monitoring parameters

A complete monitoring unit usually monitors the following parameters:

Wind speed and direction
Light intensity
Ambient temperature and humidity
Wind turbine speed, output voltage and current
PV array output voltage and current
Battery voltage, current, temperature and state of charge (SOC)
Load power consumption
Inverter working status

6.2 Data acquisition and processing

The monitoring unit collects the above parameters through various sensors, and then processes and analyzes the data. This usually includes:

Data filtering: remove noise and improve data reliability.

Data calibration: calibrate according to sensor characteristics to ensure data accuracy.

Data fusion: combine data from multiple sensors to obtain a more accurate estimate of the system state.

Trend analysis: analyze the trend of parameter changes and predict possible problems.

6.3 Remote monitoring and management

Real-time monitoring: managers can check the system operation status at any time.

Remote control: remote adjustment and control when necessary.

Fault alarm: when the system is abnormal, an alarm is issued in time.

Data recording: long-term recording of system operation data for performance analysis and optimization.

Software upgrade: remotely update the controller software to improve system performance.

6.4 Application of artificial intelligence in monitoring

With the development of artificial intelligence technology, more and more wind-solar complementary systems have begun to introduce AI technology to improve the intelligence level of monitoring and management. AI can play a role in the following aspects:

Fault prediction: through machine learning algorithms, analyze historical data and current operating parameters to predict possible faults.

Performance optimization: automatically adjust system parameters to achieve optimal operating efficiency.

Load prediction: predict future load demand based on historical power consumption patterns and external factors (such as weather, holidays, etc.).

Intelligent scheduling: combine power generation forecasts and load forecasts to formulate the optimal energy scheduling strategy.

Abnormal detection: use deep learning algorithms to identify abnormal patterns in system operation and discover potential problems in time.

Q wind turbine
Q wind turbine

7. Future development trends of wind-solar complementary discharge control

With the continuous advancement of technology and the expansion of application scenarios, wind-solar complementary discharge control technology is also evolving. The following are several development trends worth paying attention to:

7.1 Multi-energy complementarity

In addition to wind and solar energy, future complementary systems may integrate more energy forms, such as biomass energy, geothermal energy, etc. This will further improve the stability and flexibility of the system.

7.2 Smart Microgrid

The wind-solar hybrid system will become an important part of the smart microgrid. Through advanced control algorithms, energy exchange and coordinated operation between multiple microgrids can be realized.

7.3 Big Data and Cloud Computing

Using cloud platforms and big data technologies, centralized monitoring and management of multiple wind-solar hybrid systems can be achieved, improving overall operating efficiency.

7.4 Blockchain Technology

Blockchain technology may be used for energy trading and management, realizing point-to-point energy trading, and improving the flexibility and economy of the system.

7.5 New Energy Storage Technology

With the development of new energy storage technologies (such as solid-state batteries, liquid flow batteries, etc.), the energy storage solutions of wind-solar hybrid systems will be more diversified, and the system performance will be further improved.

7.6 Artificial Intelligence and Deep Learning

AI technology will play an increasingly important role in all aspects of wind-solar hybrid systems, from power generation prediction to load management, to system optimization, all will benefit from the powerful capabilities of AI.

Conclusion

Wind-solar hybrid discharge control technology is the “intelligent brain” of the new energy system. It achieves efficient use of renewable energy by coordinating wind energy, solar energy, energy storage and load. As practitioners and observers in the field of new energy, we are full of expectations for the future of wind-solar hybrid technology. It not only represents technological progress, but also symbolizes the determination and efforts of human society to transform to a sustainable development model. Let us look forward to the greater role of wind-solar hybrid technology in the future energy revolution.

learn more:Wind-Solar Hybrid Systems: What Are They and Are They the Future?

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