1. Resistive load bank:

• Principle: The resistive load bank is based on the electrical characteristics of the resistor and is usually composed of multiple adjustable resistors. By adjusting the size and connection method of the resistor, the simulation of different loads can be achieved. When the power supply voltage is applied to the load bank, the resistive load will absorb the power output of the power supply and convert it into heat energy to dissipate. 

• Features: Simple structure, low cost, easy to operate and maintain. It can simulate pure resistive loads and meet some occasions where the load characteristics are not required.

  
  

2. Inductive load bank:

• Principle: The inductive load bank uses the inductive effect of the inductive element in the AC circuit. It usually contains one or more adjustable inductance elements. By adjusting the size and connection method of the inductance, the simulation of different loads can be achieved.

•  Features: It can accurately simulate the load characteristics of inductive loads such as motors, transformers and other equipment. It is of great significance to study the influence of inductive load on power supply in power system, but inductive components are large in size, heavy in weight and poor in portability.

  
  

3. Capacitive load bank:

Principle: Capacitive load bank can accurately simulate the load characteristics of capacitive load, such as capacitor bank, reactive compensation device, etc. It usually simulates the load by switching capacitors of different capacities.

o Features: Capacitive load bank can be used to test the performance of power supply under capacitive load, which is very effective for the research and testing of capacitive load in power system. However, the withstand voltage of capacitor components is limited, and multiple capacitors need to be connected in series in high voltage test scenarios.

4. Combination load bank:

• Principle: Combination load bank can simulate multiple load characteristics at the same time, such as the combination of resistive, inductive and capacitive loads. It usually contains multiple components, and simulates complex loads through different combinations23.

• Features: It can more realistically reflect the actual load situation and conduct a comprehensive test on the performance of power supply equipment under complex loads. However, the internal structure is complex, the equipment cost is high, and the maintenance is difficult.

5. Intelligent electronic load bank:

• Principle: The intelligent electronic load bank has multiple working modes, such as constant current, constant voltage, constant resistance, constant power, etc. It can automatically adjust the load according to the test requirements, and connect with a computer or other equipment to achieve remote control and automated testing.

• Features: convenient and flexible operation, high test efficiency and accuracy. But the price is usually high, and the requirements for the use environment are high.

In summary, the principle differences of different types of load banks are mainly reflected in their simulated load characteristics, internal structure and application scenarios. When choosing a load bank, you need to choose the appropriate type according to the specific test requirements and scenarios.