Heat pumps are energy efficient heating and cooling solutions for both homes and light commercial buildings. The core of a heat pump is the scroll compressor that ensures that low pressure refrigerant is compressed to a high temperature and pressure. A major issue with such compressors, especially in single-phase installations, is the large starting current required – typically around 5 to 7 times the compressor rated current.
This may cause the electricity supply network to suffer from large voltages drop disturbances leading to light flickering and in some cases also nuisance tripping of protection devices such as moulded cases circuit breakers (MCCBs). For loads driven by generator sets or inverters, such high starting currents will require considerable over sizing of such equipment resulting in high capital investment for the end user. Many homes with heat pump installations are only provided with single-phase electricity supply.
This may cause the electricity supply network to suffer from large voltages drop disturbances leading to light flickering and in some cases also nuisance tripping of protection devices such as moulded cases circuit breakers (MCCBs). For loads driven by generator sets or inverters, such high starting currents will require considerable over sizing of such equipment resulting in high capital investment for the end user. Many homes with heat pump installations are only provided with single-phase electricity supply.
During the past 10 years Carlo Gavazzi Malta has developed a complete family of soft starters for both single-phase and three phase heat pumps. As a result of this experience, Carlo Gavazzi is engaged with world leading heat pumps manufacturers who have always expressed the need for more reliable single-phase solutions to overcome the challenges they face with their customers.
Faced with these requirements, Carlo Gavazzi embarked on a research project, in collaboration with the Department of Industrial Electrical Power Conversion at the University of Malta, for next-generation single-phase soft starters, called 'High Dynamic Motor Starter' (HDMS). This collaborative project is funded by the MCST R&I Fusion Technology Development Project.
The innovative soft starter technology will use the latest state-of-the-art IGBT switching devices in a novel circuit topology.
A dedicated control algorithm is used to achieve an excellent current reduction and stability. The research at the University of Malta focuses on the verification and improvement of the current control algorithm and the dynamic performance of IGBT switching devices in the soft starter circuit. The industrial partner is preparing the final product development for the commercial market. Prototypes of this soft starter have already been built and trial tested in heat pump installations in UK, France, Ireland and USA. Further single-phase induction motor applications are currently being studied to investigate additional potential application for this novel solution. The results so far show a very good operation which will make way for a very successful innovative product, to be developed and manufactured in Malta.