The require­ments for modern refrig­er­a­tion and venti­lation systems have changed signif­i­cantly in recent years. In addi­tion to tradi­tional para­me­ters such as airflow and pres­sure, the focus today is increas­ingly on energy effi­ciency, control­la­bility, noise perfor­mance, and system inte­gra­tion. At the same time, regu­la­tory require­ments are increas­ingly shifting the eval­u­a­tion of fans to the system level.

Against this back­drop, EC tech­nology has estab­lished itself as the stan­dard for fan drives. Its advan­tage stems not from a single char­ac­ter­istic, but from the inter­play of effi­ciency, intel­li­gent control, and system inte­gra­tion.

Oper­ating Prin­ciple and Tech­nical Funda­men­tals of EC Tech­nology

EC motors are perma­nent magnet-excited synchro­nous machines with inte­grated power elec­tronics. Commu­ta­tion is performed elec­tron­i­cally, elim­i­nating mechan­ical wear parts and enabling precise control of the current flow.

The elec­tronics perform several func­tions simul­ta­ne­ously: they convert alter­nating current to direct current, generate a vari­able rotating field, and synchro­nize it with the rotor posi­tion. This results in oper­a­tion with mini­mized losses with uniform torque. Unlike AC systems, the control is directly inte­grated. The fan is thus designed as a complete mecha­tronic system in which the motor, elec­tronics, and control are opti­mally inte­grated.

This inte­gra­tion enables:

• step­less speed control
• stable oper­a­tion
• inte­gra­tion into higher-level systems

AC vs. EC Tech­nology: Tech­nical Compar­ison

Crite­rion	AC tech­nology	EC tech­nology
Motor prin­ciple	Asyn­chro­nous with slip	Synchro­nous with perma­nent magnet
Control	external control required	Inte­grated
Speed response	limited vari­ability	contin­u­ously vari­able
Effi­ciency	load-depen­dent	High across the entire range
System inte­gra­tion	Low	high

The key differ­ence lies in slip: In AC motors, system-related losses arise from the differ­ence between the rotating field and the rotor. EC motors avoid these losses through synchro­nous oper­a­tion.

Why EC Tech­nology Is More Effi­cient

The higher effi­ciency results from several factors: In an AC motor, torque is gener­ated via induced rotor currents—a loss mech­a­nism inherent to the design. EC motors, on the other hand, use perma­nent magnets and generate torque directly. This completely elim­i­nates rotor losses. At the same time, elec­tronic commu­ta­tion ensures precise current control and mini­mizes reac­tive power. Addi­tion­ally, EC fans are designed as direct-drive systems, thereby avoiding further losses caused by external compo­nents. The key point: Effi­ciency is achieved at the system level, not just within the motor.

Demand-Driven Oper­a­tion as a Key Effi­ciency Lever

In real-world appli­ca­tions, air demand fluc­tu­ates contin­u­ously. This is primarily due to vari­able usage and load condi­tions within the facility. For example, in office build­ings, the required fresh air flow rate drops signif­i­cantly when rooms are unoc­cu­pied, as less mois­ture, CO₂, and heat need to be removed.

Dynamic load profiles also occur in other appli­ca­tions: In data centers or indus­trial processes, waste heat varies depending on current utiliza­tion, causing the required airflow to change contin­u­ously as well. Addi­tion­ally, factors such as outdoor temper­a­ture, system condi­tion, or instal­la­tion envi­ron­ment influ­ence the fan’s actual oper­ating point.

Conven­tional systems often respond by throt­tling, which restricts airflow without reducing energy consump­tion propor­tion­ally but does not utilize energy effi­ciently. EC fans use speed control as the central control vari­able. This is based on the fan laws, according to which power consump­tion increases approx­i­mately with the cube of the speed (P ~ n³). This char­ac­ter­istic makes partial-load oper­a­tion the greatest lever for energy savings. This means that even a moderate reduc­tion in speed leads to dispro­por­tion­ately large energy savings.

A concrete example illus­trates this rela­tion­ship:
If a fan’s speed is reduced from 100% to 80%, the power consump­tion is calcu­lated as follows:

The fan thus requires only about 51% of the orig­inal elec­trical power. Despite a rela­tively small speed reduc­tion of 20%, energy consump­tion is reduced by nearly half.

The effect becomes even more pronounced during heavy partial-load oper­a­tion:
At 50% speed, the result is:

This means the fan now requires only 12.5% of its orig­inal power.

In prac­tice, this means: Espe­cially in appli­ca­tions with vari­able load profiles — such as in building services or refrig­er­a­tion tech­nology — the greatest savings poten­tial lies not in full-load oper­a­tion, but in the partial-load range.

Grid Behavior and Elec­tro­mag­netic Compat­i­bility (EMC) in EC Fans

The use of power elec­tronics is a key prereq­ui­site for the high effi­ciency and control­la­bility of EC fans. At the same time, it entails specific require­ments regarding elec­trical grid behavior. Since EC drives operate inter­nally with a recti­fier, DC link, and inverter, they are nonlinear loads. The current drawn there­fore devi­ates from the ideal sinu­soidal wave­form and contains harmonics. These distor­tions can be described as Total Harmonic Distor­tion (THD) and can affect both power quality and the behavior of other connected loads.

For inte­gra­tion into indus­trial and HVAC systems, a dedi­cated EMC design approach is there­fore required. Modern EC fans already take these aspects into account during devel­op­ment: Through coor­di­nated filter concepts, opti­mized switching strate­gies, and careful design of the power elec­tronics, both conducted and radi­ated inter­fer­ence emis­sions are mini­mized. In addi­tion, immu­nity to external influ­ences is tested to ensure stable oper­a­tion even in complex systems. To this end, ebm-papst utilizes exten­sive EMC labo­ra­tory infra­struc­ture with various measure­ment envi­ron­ments and testing capa­bil­i­ties for a wide range of appli­ca­tions. This allows both emis­sions and immu­nity to be system­at­i­cally vali­dated and opti­mized. The central chal­lenge here is: How can the fan be made as grid-friendly as possible despite its power elec­tronic connec­tion?

Active PFC: Power Factor Correc­tion to Reduce Grid Inter­fer­ence

A key tech­no­log­ical solu­tion to this chal­lenge is Active Power Factor Correc­tion (Active PFC). Without appro­priate measures, the nonlinear current consump­tion of EC drives leads to an poor power factor: current and voltage are out of phase, and the current wave­form contains addi­tional harmonics. This reduces the usable active power while simul­ta­ne­ously increasing the load on the power grid. Active PFC circuits specif­i­cally address this behavior. They actively shape the drawn current so that it is as sinu­soidal as possible and in phase with the mains voltage. This signif­i­cantly improves the power factor and reduces the impact on the elec­trical grid.

In prac­tice, this results in several key advan­tages: harmonic distor­tion is reduced, energy is trans­mitted more effi­ciently, and grid stability increases—especially in systems with many fans oper­ating in parallel, such as in data centers or large venti­lation systems. Thus, Active PFC does not func­tion in isola­tion as a feature of power elec­tronics, but rather as an inte­gral part of a compre­hen­sively opti­mized overall system that oper­ates both effi­ciently and in a grid-friendly manner.

Tech­nology Lead­er­ship and Expe­ri­ence

EC tech­nology was first used by ebm-papst in fans over 50 years ago and has been contin­u­ously refined.

This expe­ri­ence is partic­u­larly evident in:

• robust system solu­tions
• high reli­a­bility
• opti­mized system inte­gra­tion

The combi­na­tion of expe­ri­ence and inno­va­tion forms the foun­da­tion for today’s state-of-the-art tech­nology.

FAQ – Frequently Asked Ques­tions About EC Tech­nology

Conclu­sion on EC Tech­nology in Venti­lation Tech­nology

EC tech­nology repre­sents the state of the art in fan tech­nology today. Its strength lies partic­u­larly in the combi­na­tion of high energy effi­ciency, precise control­la­bility, and inte­grated system func­tion­ality. Unlike tradi­tional drive concepts, the fan is no longer viewed in isola­tion but as part of a networked system whose oper­ating point can be contin­u­ously adjusted to real-world require­ments. This helps prevent energy losses while simul­ta­ne­ously opti­mizing stability, noise perfor­mance, and service life.

EC tech­nology shows its full poten­tial partic­u­larly with vari­able load profiles: The combi­na­tion of vari­able-speed oper­a­tion, inte­grated elec­tronics, and systemic opti­miza­tion leads to signif­i­cant effi­ciency gains in real-world plant oper­a­tion. With increasing digitalization—such as through networked solu­tions and data-driven analysis—the fan is also evolving into an intel­li­gent system compo­nent that actively contributes to increased effi­ciency and oper­a­tional reli­a­bility. With NEXAIRA, ebm-papst has intro­duced the first digital ecosystem for intel­li­gent venti­lation appli­ca­tions. As a result, EC tech­nology is no longer just an option, but the preferred solu­tion in most appli­ca­tions.