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Gas cell powered autos have gotten a vital a part of the electromobility transformation. The core element of the powertrain is the electrochemical reactor, often known as the gas cell stack. Commissioning is carried out on take a look at benches the place all important features are examined. Afterwards, the necessities for all the gas cell-electric drive are checked with a system validation. All fundamental knowledge of all the system should be measured with excessive precision for the efficiency parameters may be verified.
Background
The gas cell stack is a collection of particular person gas cells, the place the vitality from the chemical response of constantly provided hydrogen and atmospheric oxygen is transformed into electrical vitality in “chilly combustion”. This requires a exact working system that feeds hydrogen, atmospheric oxygen and moisture to the stack. The stack is temperature managed by a cooling system. The gas cell present is a measure of the present density occurring within the stack. Relying on the traits of the gas cell, the output present results in an precise gas cell stack voltage. The present and voltage should be measured synchronously. This stack voltage consists of the variety of gas cells within the stack. With out energy output, the gas cell stack has a sure open circuit voltage which can also be managed in all take a look at runs.
The gas cell-electric drive is often an entire subsystem of the car supplied by a provider. The general car efficiency and dynamics is the results of the electrical drive mixed with the opposite powertrain subsystems. The traits, features and properties of the gas cell-electric drive are verified on take a look at benches as much as manufacturing launch by way of numerous exams. The vitality from the gas cell stack is delivered to the DC/DC converter, which serves all different high-voltage parts of the car. They’re interconnected by way of the high-voltage car electrical system. The ability electronics of the DC/DC converter additionally include vital features, reminiscent of setting the stack setpoint present for the respective working mode. The DC/DC converter additionally comprises a lift converter, for instance to 700 V for the drivetrain (inverter and e-motor) and the traction battery.
Gas cell electrical autos often have various working modes, relying on the chosen working technique and desired driving dynamics. The gas cell stack supplies the required electrical vitality for each the traction drive and battery charging.
SEE ALSO: CSM’s free webinar on the Charged Digital Convention:
Purposeful Check And Measurement Of Gas Cell Electrical Drive System
Problem
The practical exams cowl all working features such because the cooling circuit, cooling management, heating, hydrogen (anode) paths, air (cathode) paths, high-voltage electrical circuits, sensor expertise and gas cell management unit. Due to this fact, high-precision measurement of all kinds of bodily parameters is required for the practical testing and validation of gas cell drive programs. Along with temperatures, volumetric flows, humidity and pressures, measurements of currents and voltages within the high-voltage circuits are crucial. From these, the delivered vitality, energy and effectivity are calculated.
The person sub-systems for hydrogen, air and cooling circuits are individually utilized and commissioned. An outlined start-up course of is carried out to begin the gas cell system. After that, the precise system features are examined: Chilly begin habits, warm-up section period, working factors, thermal administration or the cooling circuits. A practical take a look at proves whether or not the system behaves because it ought to, for instance whether or not all management parameters are set appropriately.
With validation, the system necessities reminiscent of efficiency parameters, response velocity to load modifications or service life are confirmed with car exams and endurance runs.
Present, voltage and energy measurements are used to test right operation in these numerous working phases. For instance, the attribute curve of the facility through the warm-up section, for start-up, load modifications, partial load and peak load in addition to numerous different distinctive working factors.
The voltage ripple occurring within the Excessive Voltage DC circuit should be checked, as a result of limits are outlined for magnitude and slope. The allowed ripple present load, for instance, at peak load should even be verified.
With the measurement of currents, voltages and powers within the high-voltage paths, all transient processes are additionally checked. For instance, when the gas cell stack is switched on or when subsystems such because the air compressor or the cooling system are switched on. Right here, the present and voltage curves should be measured at a excessive sampling price of 1 MS/s to be able to caputre voltage dips, amplitude slopes, ripple magnitudes and interfering subharmonic frequency parts.
In the end, the required effectivity curves of the gas cell-electric drive are decided. The effectivity is the vitality delivered in relation to the hydrogen consumed. It will depend on the load level and the optimum provide of the totally different media: hydrogen, atmospheric oxygen, humidity and cooling. A non-optimal provide, for instance of stack humidification, results in a drop in stack voltage.
Correct measurement and evaluation of present, voltage, energy and effectivity confirm and show all system-relevant efficiency parameters of the gas cell electrical drive.
Measurement answer
The Vector CSM E-Mobility Measurement System (www.csm.de/ev-ems) consists of all crucial {hardware} and software program to carry out these required measurements and analyses.
For direct present, voltage, and energy measurement, a Excessive-voltage Breakout Module 1.2 (www.csm.de/ev-bm) is inserted within the HV+ and HV- cables between the DC/DC converter and the battery. Extra Breakout Modules (HV BM 1.1) measure the currents of the air compressor and the cooling system. Easy present measurement may be carried out by way of CAN at pattern charges of, 1 kHz, for instance. For quick measurements of present, voltage and energy as much as sampling charges of 1000 kHz can be utilized, by way of EtherCAT® (ECAT) bus. For present measurements inside auxiliaries, CSM LEM sensor packages can be utilized, to be related by way of analog-to-digital modules (AD4 MiniModules) additionally on the ECAT bus.
The AD4 ECAT MiniModules are used to time-synchronize the measurement of all different voltages required for verification.
The measured values from CSM’s ECAT modules (HV BM’s and AD4’s) are despatched to the XCP-Gateway, which converts the information into the XCP-on-Ethernet protocol and transmitted to the information acquisition pc.
On the stack provide, all vital bodily parameters are measured with extra CSM high and low voltage modules with decrease sampling charges on a CAN bus. The sensors for measuring quantity flows, strain and humidity are related to standard and high-voltage secure CAN MiniModules (www.csm.de/ev-hvmm). Temperatures are measured at high-voltage important factors by way of HV TH8 evo modules. THMM 16 MiniModules are used at different measurement factors.
Advantages
With the standard and high-voltage measurement modules from CSM, the take a look at bench and car may be outfitted to fulfill the precise measurement necessities. Excessive-voltage secure modules are used the place measurements factors are in high-voltage surroundings. EtherCAT measurement modules enable a excessive sampling price to guarantee that high-speed transient knowledge isn’t missed.
Excessive voltage breakout modules enable direct measurement of excessive currents and voltages with calculation of instantaneous energy within the HV cables. Measurement knowledge are despatched by way of conventional CAN, or by way of EtherCAT for quick measurements with a sampling price as much as 1 MS/s.
CSM LEM sensor packages are used for present measurements at installations with house constraints. These present transformers are related by way of a CSM ADMM4 measuring module, which additionally performs the simultaneous voltage measurement.
The combination right into a take a look at bench software program like ETAS INCA for quick measurement could be very straightforward: The software program add-ons “CSM INCA AddOn ETH” permits a simple integration of the CSM measurement modules into the INCA measurement and evaluation software program from ETAS. The configuration is well accomplished by way of a custom-made consumer interface.
For correct energy evaluation, the Vector software program vMeasure exp with the eMobility Analyzer is right.
To be taught extra, register for CSM’s free webinar on the Charged Digital Convention:
Purposeful Check And Measurement Of Gas Cell Electrical Drive System
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