VONSCH
VONSCH is a Slovak developer and manufacturer of custom power electronics, including traction inverters and drives, headquartered in Brezno in central Slovakia.
VONSCH spol. s r.o. dates its origins to 1990 and was entered in the Slovak commercial register on 22 July 1992 at the District Court of Banská Bystrica. It remains privately held and passed to second-generation family owners in 2022.
It is headquartered at Budovateľská 13 in Brezno, in the Banská Bystrica region. Filed accounts put turnover at EUR 2.4 million for 2024, against a self-reported EUR 3.9 million for 2023, with staff numbers in the low twenties. The company develops, manufactures and services its products in-house.
Traction inverters and drives
VONSCH builds its traction inverters and converters as customised drives around vector control of AC motors, powered from traction batteries or DC overhead trolley lines. A control package for mining locomotives followed in 2009 under the LOCO Control designation; the current portfolio is marketed simply as customised traction drives. Each drive is engineered to the customer’s specific technical and operational parameters rather than sold as a standard product, with auxiliary circuits such as control of sanders, hydraulics and battery charging.
By the company’s own account, mining locomotives are its most frequent traction application; its drives include units certified under the EU directives for equipment in explosive atmospheres (ATEX); and its reference projects run from the 1996 drive for LEA, the first Slovak electric car, through MVA electric trucks to the control system for the Desim EE90 mining locomotive shown in Poland in 2009. The traction work is concentrated in mine haulage and road electric vehicles rather than main-line rolling stock.
Wider portfolio and markets
Traction and propulsion is one line within a broader power electronics programme. VONSCH also produces frequency converters spanning 370 W to 1400 kW, including the UNIFREM family, alongside softstarters, photovoltaic inverters, converters for small hydropower plants, and artificial AC mains with customer-defined frequency and amplitude.
The UNIFREM 690 generation covers motors rated from 315 kW to 1400 kW at 690 V supply voltage, with vector control of both induction and synchronous motors. These converters are built to order and delivered as enclosed units.
Published reference projects cover Slovakia, the Czech Republic, Poland, Turkey and Iraq. Deliveries reached Cuba in 2004 and Ethiopia in 2005, and a Serbian representation dates from the same period. Core customer segments are industrial drives, mining and energy.
Current activity
In 2024, VONSCH produced power electronics for hybrid trolley-battery locomotives delivered to Australia. In February 2026 it documented a hardware-in-the-loop testing room built for TL30 locomotives in South Australia, and an overhaul of an AE60Pb battery locomotive in which the traction system moved from lead-acid batteries to the company’s own Li-ion LV01 modules.
On the development side, work on the NEXIBOOST family of bidirectional DC-DC converters — rated up to 140 A DC and 1000 V DC — began in 2023 for mining locomotive applications, and development of the next NEXIFREM generation of frequency converters started in 2024. In June 2026 the NEXICONTROL range of solar and battery-storage inverters, up to 200 kVA, was certified for connection to the Czech distribution network by the testing laboratory of the energy group ČEZ.
