Cuk Converter with PMBLDC Motor

Hello, I am using the Cuk converter along with PMBLDC motor with following rating - Rated power: 0.816 kW; rated speed: 1500 r/min; rated torque: 5.2 N · m; poles: 6; stator resistance (R): 3.57 Ω/ph; inductance (L +M): 9.165 mH/ph; back EMF constant (Kb):1.3 V · s/rad; inertia (J): 0.068 kg · m2;

Coverter design values Vdc =298 volts ,Vs=220v and Is(source current) rated = 4.5 A The design values are obtained as Li = 6.61 mH, C1 = 0.3 μF,Lo = 0.82 mH, and Cd = 1590 μF. duty ratio =60%

the block i am using for BLDC motor is the PMSM from simpower block.

1. Do i need to put the additional load resistance also with this motor? if yes how to calculate that. In my model the dc link voltage is not boosting up to required 298 volts?. What may be the reasons.Suggest what may be wrong.. 2. How to calculate the voltage constant for this motor? Currently my value is 136.1. Is it correct?

Answer 1

[Joel Van Sickel]

There are 2 seperate issues here. First, the Cuk converter may not be getting you to the required voltage. As this required a closed loop controller, it is impossible to know why this is happening without an example model of the system. The issue could be in the modelling of the converter, or the implementation of the control aglorithm, or model settings. There is also the possiblitity the converter is not designed correctly to handle this load, although I don't think that is the issue here.

2. the next iss is determining if you have the correct motor paramters. The help file for the model explains how to calculate the Voltage constant, but you can also choose a different constant to calculate if you find that easier.