site.btaProf. Encho Popov - The Bulgarian Guru of Electric Machines

Prof. Encho Popov was an erudite scientist working in the field of electric machines, a man who did not use reference books and special software, and all the formulas were in his head. A true guru of electrical machines, on which he worked at all hours to realize his new ideas to perfection. This is how Atanas Hristozov, owner of the Almott Ltd. company of Stara Zagora (Southern Bulgaria), described Popov - a prominent Bulgarian inventor in the field of electrical engineering. The scientist worked at Almott from 2013.

Prof. Encho Popov was born on December 15, 1935 in the town of Tsar Kaloyan (Northeastern Bulgaria) and died there on January 5, 2023. He graduated from the Technical University of Sofia with a degree in Electrical Engineering.

He filed applications for 154 inventions with the Bulgarian Patent Office and holds dozens of patents in force in Bulgaria and abroad. He received the Inventor of the Year Award three times. He was listed in the Golden Book of the Bulgarian Patent Office in 1999. In 2011, his brushless alternator with claw poles was granted a patent by the US Patent and Trademark Office, under which an American company bought from Bulgaria the most powerful alternators in the world. Among his patents in force are a stator with ventilation channels for an electric machine, a brushless electric machine with excitation by permanent magnets, etc. (Almott Ltd.)

It all began in the late 1960s, when the scientist was involved in the development of the drives of all Bulgarian machine tools made in the factories in Sliven, Troyan, Nova Zagora and Pazardzhik, said Hristozov. The drives were developed by a team led by the Bulgarian scientist. At that time, Prof. Popov visited Japan to get acquainted with the work of the world leader in the production of Fanuc electric drives. With Popov's help, Bulgaria became a world leader in the production of CNC machine tools in the 1980s.

In 2006, the first project that directly connected Atanas Hristozov with Prof. Popov was the development of a high-power alternator for the US automotive industry. It went into production for the needs of a large US company in the summer of 2007, and the invention was registered at the Bulgarian Patent Office on April 16, 2007.

With its unique design, the alternator is applicable to public transport buses with low-carbon internal combustion engines. It powers the vehicle's onboard electric water pump and fans. Those buses need a more powerful alternator, Hristozov explained, adding that none was available in the US market.

After starting work at Almott in the spring of 2013, the scientist registered more than ten Bulgarian patents in the US, Canada, Britain, Germany, France and China. The company manufactures brushless electric machines for vehicles, for drives of individual units in self-propelled platforms, construction machinery and small vessels.

In recent years, under the leadership of Prof. Popov, an Almott team has put into production some of those patents with support from the National Innovation Fund.

"Prof. Encho Popov was a special person. He lived for and through electrical engineering. He would call you at midnight and ask you about the diameter of the generator we were making for Lucas. To him, tasks and technical issues mattered most, it will be some time before someone like him is born," Assoc. Prof. Eng. Georgi Georgiev said.

Popov was a reviewer of Georgiev's thesis in the late 1960s and invited him to join the enthusiastic young team at the Research and Design Institute of Electrical Engineering Industry that developed all direct current motors for the electric trucks which were developed and produced in Bulgaria at the time, generators and starters for cars, motors for feed and main drives of CNC machine tools. "Bulgaria was number one among the socialist countries, as well as in the world, in terms of those electric drives. They were used in Bulgaria and exported to Russia, China and other countries. Thanks to innovative solutions, feed drive motors earned the description 'non-magnetizing'," said Georgiev.

There are more than 50 inventions from this period and most of them were made under the guidance of Prof. Encho Popov. They were registered in the US, Britain and Russia, to name a few.

Over the years, Popov directed developments in the field of automotive alternators and starters, spindle and high-frequency permanent magnet motors for CNC machine tools, electric motors for computing equipment, and lift truck motors. He worked in close cooperation with the Institute of Metal Science, Technology and Equipment with the Bulgarian Academy of Sciences, as well as with the Technical University of Sofia. Based on these developments, large-scale electrical engineering plants were developed, in which more than 30% of his inventions were implemented. Bulgaria was the global leader, ahead of the US, Germany and Japan, in the production of spindle and high-frequency motors.

He holds over 100 patents in the field of electrical engineering, with more than 20 recognized in the US, Britain, Canada, France, Germany and Russia. He is the inventor of over 80 inventions with a tremendous contribution in the field of electrical machinery. His developments have exceeded the world standard of 3% industrial invention applicability.

In March 2015, Prof. Popov was honoured with the 2014 Grand Prize of the Electric Vehicle Industry Cluster, the industry organization of manufacturers of components, parts and services for the conversion or production of electric vehicles. The Khan Kubrat's Sword Award was conferred on Popov for the development and production of a basic model of a permanent magnet, liquid cooled 75 kW, 400V synchronous electric motor patented in Bulgaria, the EU and the US.

Electric motors for electric vehicles and electric boats developed by Prof. Popov were granted a patent from the Patent Office of China in 2020 and were patented in the US. 

In 2016, Encho Popov was awarded the Order of the Balkan Range, First Class, for his outstanding services in the field of science and the development of electrical engineering. 

In recent years, he was active in the field of motor alternators for a mini-hybrid system for electric cars and electric motors for electric cars and hybrid cars. 

This story is based on information gathered by the Bulgarian Patent Office (BPO) and BTA's Archives and References Directorate.

The story about Prof. Encho Popov is published within the framework of a partnership initiative between BTA and BPO, which envisages the presentation of Bulgarians listed in BPO's Golden Book and the activities of the Patent Office in a joint weekly column entitled "Created in Bulgaria".