Power electronics for new requirements affecting grid harmonics

Challenge

The global shift to a more CO2-neutral technology-based energy paradigm has increased the introduction of mains-powered electronic power supplies / converters, which are expected to grow in number by a factor of 3 from 2009 to 2035.

Electronic power converters are a key component for flexibly and reliably converting electrical energy from renewable energy sources, such as solar energy, for charging electric vehicles, charging mobile phones and computers, powering LED lamps, and much more. The process of converting the energy involves generating electrical impulse signals in the converter. This leads to unwanted electrical noise emissions from the conversion process, which could cause unintended reactions in the power grid and other users on it.

While there are limit values for electrical noise from 150 kHz and upwards applicable to all types of mains-powered devices, the frequency range 9 kHz to 150 kHz is only regulated in a select few standards. There are currently no international standards for the range between 2 kHz and 9 kHz. IEC Technical Committee 77A is only now in the process of developing emission requirements for the entire frequency range from 2kHz to 150 kHz.

Interference between devices on the grid has been observed at frequencies where both current converters and (e.g.) remotely read equipment, like certain electricity meters, operate simultaneously. When the number of current converters increases (and the expected increase in the number of renewable energy products is 100% by 2030), the probability of interference between converters and devices, as well as between multiple converters, is expected to increase. It is estimated that the number of smart meters in Europe will reach approximately 240 million within the next two years (2.7 million of which will be in Denmark alone). This highlights the importance of electrical noise on the power grid in the 9 kHz to 150 kHz frequency range. The AAU-ET has identified noise contributions from various functional parts of a power converter. With knowledge of the propagation of noise, it is possible to build usable models and design circuit components and filter circuits to minimize interference.

Solution idea

The aim of the project is to develop and describe a method and guidance for the selection and design of a current converter that can meet or exceed emission requirements in the 9 kHz to 150 kHz frequency range, and which can coexist with a large number of other converters in (e.g.) an office area, a household, or mains power from the same safety group / supply board.

Project goals and target group: The project’s target group(s) can be summarized as follows:

• Target group 1: Danish companies that provide consulting assistance to, or themselves develop, designs for power supply solutions or motor controls.
• Target group 2: Danish companies that manufacture or are end users of products supplied with power from the low-voltage grid (230 VAC / 400 VAC), such as industrial motor controls, heating, ventilation, pumps, and general electronics.
• Target group 3: Danish manufacturers of maritime and defence/military products, where it can already be difficult today to identify suitable current converters. These target groups will also benefit from updates on developments in the field of standardization and EU requirements specifically for the 9kHz to 150kHz frequency range.

Partnere

• FORCE Technology
• Aalborg Universitet
• Grundfos
• NPC Tech
• Dansk Energi
• Kamstrup A/S
• BITZER Electronics A/S
• OJ Electronics A/S
• Pascal A/S
• Vestas Wind Systems A/S
• PowerCon A/S