The decoupling of AC motor type test bench is mainly used for DC motors, which can be regarded as a DC motor used for decoupling.

1、 Let's take a look at the control mode of a DC motor. This DC motor consists of two components. The stator winding adopts direct current to form a gap magnetic field; The rotor winding is connected to the electric brush, and is powered by direct current through the electric brush. The magnetic field in the air gap generates an ampere force in the current in the rotor coil, causing the motor to rotate.

2、 By adjusting the DC voltage at both ends of the coil without considering saturation, the strength of the magnetic field can be linearly changed. Meanwhile, by adjusting the DC voltage at both ends of the rotor, the coil current can be linearly changed. By utilizing the Ampere force principle, the output power of an electric motor can be linearly varied. Why emphasize linearity? In this way, you can control the excitation voltage, armature current, and output power of the motor according to the required force.

3、 Why decouple AC motors? Let's take permanent magnet synchronous motors as an example. Using permanent magnet excitation to form a gap magnetic field. The force in the magnetic field formed by the magnet after the stator winding is powered on. However, in the stator winding, current has two functions: 1. Generating torque. 2. Generate a magnetic field (only used for manufacturing DC motors with magnetic fields).

So, how much current is used to produce torque and how much is used to produce current? If we can master this ratio, can we control it like we control a DC motor?

Therefore, after several generations of continuous attempts, Clark conversion and Park conversion finally emerged. These two methods can divide the ABC three-phase current of an AC motor into two types: axial current that directly generates a magnetic field, and quadrature axis current, that is, dq axis current. Converting an AC motor to a DC motor is easy to operate.

In short, the decoupling of the AC motor type test bench is achieved based on the control principle of DC motors, which can generate both magnetic and torque fields.