Charged EVs | “Sensible” auxiliary management options that add worth


Sponsored by KEB

Effectivity is the secret in electrical automobile design and might have an effect on automobile vary and vitality prices. For a given gadget expertise, there received’t be a lot effectivity benefit from one producer versus one other in apples-to-apples product comparability. Nonetheless, there’s one other approach to think about effectivity, and that’s when it comes to operational and useful effectivity. That’s, trying past a tool’s inherent effectivity and contemplating how and when it’s operated. That is the place “good” management options come into play and is especially relevant to electrified auxiliaries, which depend on the management of impartial electrical motors to drive auxiliaries similar to pumps and compressors reasonably than being mechanically pushed by a combustion engine.   

Sensible options function gadgets “on-demand,” which matches the output vitality provided with the precise vitality demand primarily based on the loading situations or desired operation. This strategy reduces vitality consumption and audible noise by shutting the gadget off when not in operation or working at a diminished or extra environment friendly working level. 

This moreover reduces gear put on and tear, thus extending operational lifetime or decreasing upkeep necessities. General, good options can affect day-to-day contributions to elevated automobile vary, operator consolation, and whole price of possession.

 Power-efficient and on-demand good management options may be achieved in a number of methods. This text will concentrate on good answer methods for effectively controlling auxiliaries similar to pumps and compressors and among the options of the KEB T6 Auxiliary Inverter system. The T6 is a high-voltage inverter system that helps as much as 6 impartial AC motor management outputs with modular energy choices (7.5kW, 15kW, or 30kW) for every output.              

Charged EVs Smart auxiliary control solutions that add value
KEB T6 Auxiliary Inverter (3-in-1 system)

Superior Motor Controls

Motor management strategies decide how a motor is operated and depend on an inverter’s management algorithms to manage the output energy to the motor. Thus, totally different management strategies can affect a motor’s operational effectivity. There are two major management strategies for AC motors, scalar, and vector management.   

Scalar Management

Scalar management is also referred to as volts-per-hertz management and is an open-loop management sort. Right here, the inverter outputs a hard and fast voltage output for a given frequency equivalent to a command pace primarily based on a Volts/Hertz curve from a motor’s rated working level. Because the output voltage is set by the pace command reasonably than the precise energy necessities of the load, scalar management operation may be much less environment friendly beneath partial hundreds. Scalar management additionally tends to have comparatively poor efficiency since there isn’t a pace or torque management and restricted torque accessible at low speeds. Scalar management may be very fundamental and solely applies to asynchronous induction motors. It’s outlined right here to offer context to the advantages of vector management options. 

Vector Management

A extra superior answer is vector management, also referred to as field-oriented management. This sort of management is a closed loop that makes use of suggestions from the motor. With vector management, there’s impartial management of each torque and pace. Moreover, the voltage output is optimized primarily based on a vector calculation and operates extra effectively in accordance with the precise load necessities. 

Closed-loop techniques additionally present much better pace regulation and torque management, permitting for a high-performance response. That is significantly relevant when implementing on-demand auxiliary controls options that preserve vitality by dynamically adjusting motor pace or switching techniques off/on in response to an auxiliary gadget’s instantaneous or conditional energy necessities.  

Vector management can be utilized with asynchronous induction motors for elevated operational effectivity and efficiency. In distinction, synchronous motors similar to everlasting magnet servo motors require closed-loop suggestions of the rotor place to modulate the stator electromagnetic area angle. Encoder suggestions and sensorless management algorithms have two varieties of strategies for closing the loop.  

Encoder vs. Sensorless Suggestions

The normal methodology used an encoder mounted on the motor shaft for pace and/or place suggestions. The downsides are that the encoder and the cabling are extra system parts that add price, take up house, and are potential factors of failure or inclined to electrical interference.  

As a substitute of encoder suggestions, sensorless management algorithms make the most of an observer motor mannequin primarily based on the motor traits and the precise measured motor present and voltage as suggestions to shut the loop. This eliminates the necessity for encoder {hardware} whereas offering comparable efficiency beneath most circumstances. Sensorless fashions have limitations at very low steady working speeds (<1% motor-rated pace) and wouldn’t be really helpful for traction or holding functions however are in any other case ideally fitted to use with pumps and compressors. 

When contemplating sensorless management, it needs to be famous that just some producers’ sensorless algorithms are equal. Though a comparability could also be troublesome to quantify, the important traits embrace the pace management response and the torque management accuracy. 

Moreover, the simplicity of setup needs to be thought of. KEB has been a frontrunner in sensorless management improvement and efficiency for over 15 years, with in depth expertise in pump and compressor functions throughout numerous energy ranges and industries. Moreover, the setup of sensorless management has been simplified with an automatic motor study process to characterize motors (solely fundamental motor nameplate knowledge is required). 

1667318122 552 Charged EVs Smart auxiliary control solutions that add value
Scalar vs. Sensorless Vector (plus equal circuit mannequin)

Embedded Management Options

Electrifying auxiliaries present new alternatives for a way these techniques may be managed. Past the motor management itself, good options can even make the most of modern embedded management options.  

Such options are sometimes energy on-demand management packages. These are used to manage the motor primarily based on the specified operation of the auxiliary and can even bear in mind a number of different elements throughout the automobile to find out the optimum setpoint from an energy-efficiency or efficiency standpoint. This is able to be in distinction to a combustion engine-driven auxiliary, which might depend upon engine pace. As a substitute, electrified auxiliaries may be managed independently and intelligently exactly HOW and WHEN they’re wanted.  

Energy on-demand management packages can vary from fundamental on/off management to dynamic efficiency and much more superior algorithms which use refined fashions of the auxiliary system and inputs from the automobile to calculate the motor management setpoints. 

As a use case instance, an influence steering pump can be an utility that might readily profit from good energy on-demand management options. 

Historically, an influence steering pump pushed by an engine would always produce stress and circulate. The stress is dissipated via aid valves as wasted vitality when not absolutely utilized. An electrified auxiliary can as an alternative use condition-based management packages to scale back vitality consumption. 

  • A fundamental implementation can be to function the pump motor at a diminished idle pace when the steering isn’t in-use, primarily based on the steering angle sensor pace. 
  • A extra superior implementation might calculate baseline working factors for various pace ranges because the circulate and stress necessities differ drastically primarily based on automobile pace. 
  • Much more superior options may use a hydraulic stress sensor and (sensorless) motor pace suggestions in PI management loops to extra dynamically and exactly management the required motor pace and torque primarily based on the precise demand necessities. 
Charged EVs Smart auxiliary control solutions that add value
Instance of a Sensible Hydraulic Management Mannequin

The T6 Auxiliary Inverter incorporates an embedded controller for straightforward integration of good management packages. This enables system integration builders and auxiliary techniques suppliers to implement their product know-how into customized, value-added performance with ready-to-use good software program management options for his or her clients.

Sponsored by KEB


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