How to design a diode network in a multi energy coupling system?

1, Functional positioning: The core role of diode networks
Multi energy coupling systems typically integrate various forms of energy such as photovoltaics, wind power, energy storage, and gas turbines, and their energy flow exhibits multidirectionality and dynamism. The diode network assumes three core functions in this scenario:

Reverse current blocking: When a branch experiences a voltage drop due to a fault or shadow obstruction, parallel diodes can block the reverse power supply from other branches to the faulty branch, avoiding hot spot effects or equipment damage. For example, in photovoltaic arrays, bypass diodes can short-circuit faulty branches when a single solar panel is obstructed, protecting normal solar panels from reverse current surges.
Voltage clamping and stabilization: A graded voltage clamping circuit is constructed by connecting diodes in series, which can limit the range of system voltage fluctuations. For example, in a lithium battery energy storage system, multiple silicon diodes are connected in series to form a fixed voltage drop of 1.8V. When the voltage of the battery pack exceeds this value, the diodes conduct and discharge the excess voltage to ground, protecting the backend load.
Energy Conversion Assistance: In the electric hot cold cogeneration system, diodes can assist cogeneration (CHP) units in achieving energy cascade utilization. For example, when the waste heat generated by CHP units is converted into cooling capacity through absorption refrigeration, diodes can prevent the cooling capacity from flowing back to the heat source side, ensuring system efficiency.
2, Topology structure: flexible design that adapts to multiple scenarios
The topology structure of a diode network needs to be dynamically adjusted according to the energy type, system size, and operating mode. Common structures include:

Parallel network: suitable for distributed photovoltaic, wind power and other scenarios, by connecting blocking diodes in series at the entrance of each branch, it prevents low-voltage branches from becoming "energy black holes". For example, a photovoltaic project in an industrial park adopts a parallel diode network. When a branch voltage drops due to shading, the blocking diode is cut off to prevent the normal branch from supplying power in reverse to the faulty branch, reducing power loss from 75% to within 10%.
Series network: suitable for high voltage direct current transmission (HVDC) or energy storage systems, voltage superposition and direction control are achieved through series diodes. For example, in lithium battery energy storage systems, a series diode network is used to construct a battery pack balancing circuit. When a certain battery is overcharged, the corresponding diode conducts, transferring excess energy to other batteries and extending battery life.
Hybrid network: combining parallel and series structures, suitable for complex multi energy coupling scenarios. For example, in a combined cooling, heating, and power system, a hybrid diode network is used to coordinate the three energy flows of electricity, heat, and cold: parallel diodes are used to isolate faulty branches, and series diodes are used for voltage clamping and energy conversion direction control, achieving overall system efficiency improvement.
3, Device selection: Balancing performance and cost
The selection of diodes requires comprehensive consideration of parameters such as voltage, current, frequency, power consumption, and cost. Common types include:

Silicon diode: suitable for low voltage and high current scenarios, such as photovoltaic bypass diodes. Its voltage drop is about 0.6V, with low cost but high power consumption. For example, a certain photovoltaic project uses 1N4007 silicon diodes as bypass protection components to meet the requirements of reverse voltage of 1000V and forward current of 1A, while controlling the cost of a single board within 0.5 yuan.
Schottky diode: suitable for high-frequency and low-voltage scenarios, such as switching power supplies, motor drives, etc. Its voltage drop is only 0.4V, and the reverse recovery time is short, but its voltage resistance is weak. For example, a certain electric vehicle charging station project uses Schottky diodes as freewheeling components to reduce the reverse recovery time from microseconds to nanoseconds, effectively suppressing voltage surges during motor start stop.
Silicon carbide (SiC) diodes: suitable for high voltage, high temperature, and high frequency scenarios, such as smart grids, new energy vehicles, etc. Its pressure drops to 0.2V, the reverse recovery time is extremely short, and its temperature resistance reaches over 200 ℃. For example, a high-voltage direct current transmission project uses SiC diodes to construct converter valves, reducing conduction losses by 40% and improving system efficiency by 5%.
4, Optimization strategy: Improve system reliability and energy efficiency
To further enhance the performance of diode networks in multi energy coupling systems, the following optimization strategies can be adopted:

Intelligent control integration: Combining sensors and control algorithms to achieve dynamic adjustment of diode networks. For example, in microgrids, by monitoring the voltage and current parameters of each branch in real-time, dynamically adjusting the diode conduction threshold, and optimizing energy allocation. The comprehensive energy system project in a certain region adopts an intelligent diode controller, which improves the system response speed to the millisecond level and shortens the fault isolation time by 80%.
Thermal management optimization: For high-power scenarios, reduce diode junction temperature through heat dissipation design. For example, when multiple diodes are connected in parallel, a common heat sink design is used to ensure temperature balance. A data center UPS project optimized the heat dissipation path, reducing the diode junction temperature from 150 ℃ to 120 ℃ and extending its lifespan by three times.
Modular design: Encapsulate the diode network into standard modules for quick deployment and maintenance. For example, a multi energy coupling project in an industrial park adopts a modular diode array, which increases the power support of a single module to 100kW and supports hot plugging, reducing the system expansion time from days to hours.
5, Case study: Practical application of diode network
Taking a microgrid project on an island as an example, the system integrates photovoltaic, wind power, diesel generators, and energy storage devices, and optimizes energy flow through a diode network

Photovoltaic branch protection: Connect blocking diodes in series at the entrance of each photovoltaic branch to prevent reverse current caused by shadow obstruction. Project operation data shows that the diode network has reduced the failure rate of photovoltaic arrays from 5% to 0.2%, and increased annual power generation by 8%.
Energy storage system balancing: A series diode network is used to construct a battery pack balancing circuit. When a certain battery is overcharged, the corresponding diode conducts, transferring excess energy to other batteries. Project testing shows that this design extends the lifespan of the battery pack by 40% and reduces maintenance costs by 30%.
Multi energy complementary coordination: By coordinating the flow of electricity, heat, and cold through a hybrid diode network, demand side response and dynamic scheduling are achieved. After one year of project operation, the comprehensive energy efficiency of the system increased from 65% to 78%, and carbon emissions decreased by 25%.