Validation of direct current control in LED lamp with non-inverting buck-boost converter

The given paper deals with equipment for smart lighting systems. A hypothesis, that current fed dimmable electrical ballasts with amplitude modulation of light could improve the controllability of such systems, is brought forward. Since there are very few natural current sources it is proposed to use a combination of a voltage source, switch mode voltage-to-current converter and current regulator. The first part can be built as a buck converter, while the regulator is similar to a boost converter. Together this gives a topology known as non-inverting buck-boost converter which, however, in the given case has to be controlled as two modules of “current source” nature. The control rules suitable for such strategy are discussed in the paper. In order to verify the idea a laboratory prototype of such converter has been built and tested. The features of the converter are given in the paper below. The obtained results show that the idea works in general, but certain instability and efficiency problems have to be solved. That is why it was concluded that a more accurate control method for the voltage-to-current source part has to be developed.