Future trends and innovations in motor excitation methods

The motor excitation method is the method and means adopted to create the magnetic field required by the motor. In the excitation mode, the magnetic field of the motor can be excited, so that it can generate torque and be used to drive various loads. Different types of motors and application scenarios require various excitation methods.

The main task of the motor excitation method is to generate the magnetic field required by the motor to ensure the normal operation of the motor. The choice of excitation method will directly affect the performance, efficiency and stability of the motor. Different excitation methods have different effects on the starting characteristics, speed adjustment range and response speed of the motor.

Motor excitation methods can be divided into the following types:

一. Constant magnet excitation method

The constant magnet excitation method is a common motor excitation method. It generates a stable magnetic field by connecting the field winding directly to the DC power supply. This method is suitable for situations where the load changes are small and the magnetic field needs to be stable. In the constant magnet excitation method, it can be further divided into two types: series excitation and shunt excitation.

1 . Series excitation

Series excitation refers to connecting the excitation winding in series in the main circuit of the motor and sharing a power supply with the main circuit of the motor. The series excitation method has the characteristics of simple structure and fast response speed, and can achieve a wide range of speed adjustment. However, if the field winding breaks or loses excitation, the motor will lose its magnetic field and stop running.

2. Parallel excitation

Shunt excitation refers to supplying power to the excitation winding and the main circuit of the motor separately, and connecting them to different power supplies. This method has better stability and reliability. Even if the field winding loses excitation or is disconnected, the motor can still continue to work. However, the parallel excitation method has certain requirements on the excitation power supply, and the speed adjustment range is relatively small.

3. Variable magnet excitation method

The variable magnet excitation method is a method to achieve excitation by adjusting the magnetic field intensity. It can adjust the size of the magnetic field according to load requirements to achieve appropriate speed and torque. Variable magnet excitation methods mainly include reluctance excitation, magnetic field excitation and hybrid excitation methods.

4. Magnetic resistance excitation

Reluctance excitation adjusts the excitation magnetic field of the motor by changing the reluctance in the excitation winding. By adjusting the length or cross-sectional area of the magnetic circuit in the excitation winding, the size of the reluctance can be changed, thereby controlling the strength of the magnetic field. This method has the characteristics of simple structure and stable effect, and is suitable for some situations where the speed adjustment range is not high.

5. Magnetic field excitation

Magnetic field excitation adjusts the field field of the motor by controlling the current in the field winding. By adjusting the size and direction of the excitation current, the strength of the magnetic field can be adjusted. The magnetic field excitation method has the characteristics of fast response speed and wide speed adjustment range, and is suitable for situations where high dynamic performance requirements are required.

6. Mixed excitation

Hybrid excitation is an excitation method that combines constant magnet excitation and variable magnet excitation. During the operation of the motor, the strength of the magnetic field can be controlled by adjusting the excitation current and reluctance according to changes in load to achieve adjustment of speed and torque. The hybrid excitation method can take into account both efficiency and dynamic performance, and is suitable for situations that require high stability and flexibility.

Advantages and disadvantages of motor excitation methods:

advantage:

The constant magnet excitation method has a simple structure and fast response speed, and is suitable for situations where the speed adjustment range is not high.

The variable magnet excitation method can adjust the magnetic field size according to the load demand, and has a good speed adjustment range and dynamic performance.

The hybrid excitation method combines the advantages of the constant magnet excitation method and the variable magnet excitation method, and can achieve a balance between efficiency and dynamic performance.

shortcoming:

The constant magnet excitation method will cause the motor to stop working when the excitation winding is disconnected or loses excitation.

The variable magnet excitation method has certain requirements on the excitation power supply, and the speed adjustment range is relatively small.

The hybrid excitation method may require more complex control strategies and equipment in practical applications.