PSIM User Manual phần 5 pot

Chapter 2: Power Circuit Components

2-52 PSIM User Manual

The system consists of one machine, 2 torque sensors, and 2 mechanical loads. The

torques and moment of inertia for the machine and the loads are as labelled in the diagram.

The reference direction of this mechanical system is from left to right. The equation for

this system can be written as:

The equivalent electrical circuit of the equation is shown below:

The node voltage in the circuit represents the mechanical speed ωm. The current probe on

the left represents the reading of the torque sensor No. 1. Similarly, the current probe on

the right represents the reading of the torque sensor No. 2. Note that the second current

probe is from right to left since Sensor 2 is opposite to the reference direction of the

mechanical system.

The equivalent circuit also illustrates how mechanical power is transferred. The multipli￾cation of the current to the voltage, which is the same as the torque times the mechanical

speed, represents the mechanical power. If the power is positive, it is transferred in the

direction of the speed ωm.

Load 1 Load 2

Sensor 1 Sensor 2

TL1 TL2

J JL1 JL2

Tem

J JL1 JL2 ( ) + +

dωm

dt ⋅ ---------- Tem TL1 – TL2 = –

Load 1 Load 2

Sensor 1 Sensor 2

J TL1 TL2 JL1 J Tem L2

ωm

Machine