Cows in barns require proper ventilation to support their well-being and avoid illness. Large fans hung from the roof help to dry the floor and lower humidity while also removing odors and gases produced by the livestock’s urine, manure, and breathing. This reduces hoof and udder hygiene issues, even in the winter months. During summer, excessive heat can result in cow discomfort, leading to lower reproduction efficiency and reduced milk quality and production. Ventilation systems increase airflow over the cows, reducing the risk of heat stress.

The established supplier Bioret-Agri has been supplying farmers with innovative animal comfort products since 1983, with a particular focus on dairy cows. When mounted in the barn’s rafters, their ventilation system is unique in delivering 360° of airflow, reducing the heat stress on cows (Figure 1). To further improve the product and reduce power consumption, they were looking to move from an induction motor (IM) to a permanent magnet (PM) type. This required a suitable motor inverter.

The original IM-based solution only offered a simple on/off control. The move to a PM motor provided a chance to add variable speed control that responded to the temperature in the barn. This would ensure that energy consumption was kept to a minimum and ventilation noise would be held at the lowest possible volume. With barns reaching up to one hundred meters in length, multiple ventilators can be installed along the roof’s length. Therefore, the motor inverter solution selected would need to be capable of communicating with the other ventilators to ensure a uniform airflow throughout the building.

Having reviewed the application requirements, Delta’s team of engineers proposed the ME300 Series from its broad portfolio of motor inverters. It was ideally suited to the 2.2 kW electrically commutated PM motor selected, supporting the maximum target speed of 1,800 RPM. This compact vector control drive has been reduced by 60% in volume over previous generation drives, enabling it to be easily integrated into the Bioret- Agri Cyclone 360 ventilator. The screwless design of the terminal blocks simplifies manufacturing, while its built-in Class A (C2/C3) EMC filter saves both space and the procurement of additional parts. Thanks to its optimized hardware layout and anti-pollution design, it was also ideal for resisting the dust and fibers prevalent in barns.

Like many recent projects, Bioret-Agri and Delta faced challenges during the development of the Cyclone 360 due to restrictions imposed by Covid. The ME300 can be parameterized to match the motor being driven. However, without direct access to the motor on-site, the Delta team was forced to remotely undertake the required system optimization. User control is implemented with a simple on/off signal, while a single output indicates any system errors. Ventilator speed across multiple Cyclone 360s is synchronized via an analog output that links to each subsequent ME300 motor inverter.

The Cyclone 360 operates at 20% of its maximum speed when the temperature lies between 3°C and 18°C.

As the temperature rises beyond this upper limit, the motor speed increases. In operation, the new ventilator has been shown to consume up to 32% less energy than the previous IM-based model. To further improve system functionality, it is planned to integrate the ME300’s flying catch capability in the next firmware upgrade. This allows the inverter to search for the correct drive speed, should the fan already be rotating, without first having to bring the rotor to a standstill.

"This has been an exciting project, much different from the typical industrial applications we usually address," said Jean-Charles Cuzin, Field Application Engineer at Delta Electronics. "Covid added to the development challenges, but resourcefulness and dedication by the team ensured we overcame them." Yannick Daubelcour, R&D Manager at Bioret-Agri said, "The professional support provided by Delta Electronics and the local partner, allowed us to meet our design goals. The Cyclone 360 remains an innovation leader in barn ventilation systems, and this latest design improves animal welfare by being quieter in operation and lower in energy cost."