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HomeElectric VehicleCharged EVs | “Good” electrical auxiliary management options that add worth

Charged EVs | “Good” electrical auxiliary management options that add worth


Sponsored by KEB

Effectivity is the secret in electrical car design and may have an effect on car vary and power prices. For a given machine know-how, there gained’t be a lot effectivity benefit from one producer versus one other in apples-to-apples product comparability. Nevertheless, there may be one other means to think about effectivity, and that’s by way of operational and purposeful effectivity. That’s, wanting 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 unbiased electrical motors to drive auxiliaries corresponding to pumps and compressors relatively than being mechanically pushed by a combustion engine.   

Good options function units “on-demand,” which matches the output power equipped with the precise power demand based mostly on the loading situations or desired operation. This method reduces power consumption and audible noise by shutting the machine off when not in operation or working at a decreased or extra environment friendly working level. 

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

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

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 control 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 called volts-per-hertz management and is an open-loop management sort. Right here, the inverter outputs a set voltage output for a given frequency comparable to a command velocity based mostly on a Volts/Hertz curve from a motor’s rated working level. For the reason that output voltage is decided by the velocity command relatively than the precise energy necessities of the load, scalar management operation could be much less environment friendly below partial hundreds. Scalar management additionally tends to have comparatively poor efficiency since there isn’t any velocity or torque management and restricted torque obtainable 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 called field-oriented management. This kind of management is a closed loop that makes use of suggestions from the motor. With vector management, there may be unbiased management of each torque and velocity. Moreover, the voltage output is optimized based mostly on a vector calculation and operates extra effectively in line with the precise load necessities. 

Closed-loop methods additionally present much better velocity regulation and torque management, permitting for a high-performance response. That is notably relevant when implementing on-demand auxiliary controls options that preserve power by dynamically adjusting motor velocity or switching methods off/on in response to an auxiliary machine’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 corresponding to everlasting magnet servo motors require closed-loop suggestions of the rotor place to modulate the stator electromagnetic discipline angle. Encoder suggestions and sensorless management algorithms have two sorts of strategies for closing the loop.  

Encoder vs. Sensorless Suggestions

The standard technique used an encoder mounted on the motor shaft for velocity and/or place suggestions. The downsides are that the encoder and the cabling are further system elements that add price, take up area, and are potential factors of failure or vulnerable to electrical interference.  

As a substitute of encoder suggestions, sensorless management algorithms make the most of an observer motor mannequin based mostly 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 below most circumstances. Sensorless fashions have limitations at very low steady working speeds (<1% motor-rated velocity) and wouldn’t be advisable for traction or holding functions however are in any other case ideally suited to use with pumps and compressors. 

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

Moreover, the simplicity of setup ought to be thought-about. KEB has been a frontrunner in sensorless management growth and efficiency for over 15 years, with intensive expertise in pump and compressor functions throughout varied 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). 

Scalar vs. Sensorless Vector (plus equal circuit mannequin)

Embedded Management Options

Electrifying auxiliaries present new alternatives for a way these methods could be managed. Past the motor management itself, good options may make the most of revolutionary embedded management options.  

Such options are sometimes energy on-demand management applications. These are used to regulate the motor based mostly on the specified operation of the auxiliary and may keep in mind a number of different elements throughout the car to find out the optimum setpoint from an energy-efficiency or efficiency standpoint. This may be in distinction to a combustion engine-driven auxiliary, which might rely on engine velocity. As a substitute, electrified auxiliaries could be managed independently and intelligently exactly HOW and WHEN they’re wanted.  

Energy on-demand management applications 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 car 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 by reduction valves as wasted power when not absolutely utilized. An electrified auxiliary can as an alternative use condition-based management applications to cut back power consumption. 

  • A fundamental implementation can be to function the pump motor at a decreased idle velocity when the steering isn’t in-use, based mostly on the steering angle sensor velocity. 
  • A extra superior implementation might calculate baseline working factors for various velocity ranges for the reason that circulate and stress necessities fluctuate drastically based mostly on car velocity. 
  • Much more superior options may use a hydraulic stress sensor and (sensorless) motor velocity suggestions in PI management loops to extra dynamically and exactly management the required motor velocity and torque based mostly on the precise demand necessities. 
Instance of a Good Hydraulic Management Mannequin

The T6 Auxiliary Inverter incorporates an embedded controller for simple integration of good management applications. This permits system integration builders and auxiliary methods 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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