OVERVIEW
An industry-leading open Hybrid Electric Vehicle Battery Pack Test Cell Control and Data Acquisition platform that provides the ultimate in modularity, flexibility and integration with hardware, models, and custom sensors:
- Quick and easy to deploy, configure and replicate.
- Reduce cost and complexity with a future-proof platform
- Achieve complete test coverage with a flexible platform
- Enable accurate and innovative battery tests.
- Achieve faster development times with automation and collaboration
- Adaptable to rapidly accommodate changing project requirements.
- Integration with existing systems.
- Supports multiple models including MATLAB/Simulink, AVL Boost and Cruise, Technalia DynaCar, IPG CarMaker, LabVIEW, C.
- Intuitive test sequencing and scripting via Python scripting engine.
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Challenge
As a free system integrator and turnkey supplier, Proventia provides modular test laboratories and centres for electric vehicles, engines, powertrains, hybrid systems and battery packs. Based in Oulu, Finland, Proventia wished to build a facility for climatic EV battery testing designed for both module and complete battery pack requirements for their own testing and demonstration purposes.
The test cell and infrastructure were developed by the Proventia team and test cell control and data acquisition system, and integration was provided by Austin Consultants.
Solution
The EVolution Battery Test Cell Control and Data Acquisition System is a complete, off-the-shelf solution designed for both module and complete battery pack testing. The platform has been designed with National Instruments (NI) VeriStand deterministic real-time test engine at its heart, to ensure that the system can run high-speed models and close the loop with real sensor data at rates upwards of 1kHz.
Based on the NI hardware and software platform, it has been designed with maximum flexibility and extensibility in mind. The modular system comprises:
- Test Cell Control and Data Acquisition System
- Test Cell Management Unit
- Remote Patch Panel
OPEN EXTENSIBLE HARDWARE ARCHITECTURE
Based on the NI PXI modular hardware platform, the Test Cell Control and Data Acquisition System offers a cost-effective, adaptable solution for changing hardware requirements. It is flexible to accommodate new technologies and offers an extendable chassis for increased demands.
New sensors, or bespoke protocols and be added via a simple low-cost, ‘plug-in’ upgrade.
MAIN CONTROL SYSTEM SPECIFICATION
The main control system consists of an18-slot NI PXIe chassis fitted with a quad-core 2.6 GHz i7 processor running a real-time operating system, for maximum determinism. Both can be upgraded to increase system bandwidth and processing power if required in the future. This system allows high-speed models to run at 1kHz. Data acquisition channels run at the same speed as the model with the exception of the high-power measurements, which include a snapshot mode for acquiring signals at 200kHz for short bursts.
TEST CELL CONTROL AND DATA ACQUISITION RACK
Test Cell Control and Data Acquisition Rack with panel removed to reveal NI PXI
To ensure that the system can adapt to changing test cell configurations the Test Cell Control and Data Acquisition system is mounted in a 29-unit rack with heavy-duty castors to allow the test equipment to be moved around on rough or uneven floors safely. To ensure flexibility to accommodate potential future expansion requirements the premium quality rack offers spare capacity with excellent options for additional mounting and wire routing.
All the DUT IO is brought out to a mass interconnect which interfaces with a remote patch panel that is housed inside the environmental chamber.
The front of the rack features an Emergency stop that is integrated into the full test cell safety infrastructure and LEDs that provide a clear indication of the safety status of the rack.
The system offers eight high speed analogue inputs and eight outputs. The communications buses offered are EtherCat and CAN(XNET). Although PROFIBUS, RS232, CANopen, can be added to the system using NI PXI cards.
Thermocouple and RTD inputs for temperature measurement are connected via the patch panel and acquired through an NI EtherCAT RIO expansion chassis, so the data is acquired deterministically.
24V DIO is provided to allow remote switching of contactors. The patch panel also has a 12V output that could be used to power a BMS
An EtherCAT expansion port allows for additional EtherCAT devices to be added to the chain where required, and communicated with deterministically.
A custom power distribution unit provides easy access to MCBs for quick resetting, and power distribution at the required voltage levels around the rack. 12V output is also available.
The cell infrastructure IO on the back features:
- Safety Integration
- Test Infrastructure Comms for battery cycler, DUT Chiller, Environmental chamber and CCTV
The rear of the rack offers connectivity to the internal gateway PC (Windows) and separate Real-Time (RT) controller, for commissioning and debugging as well as a useful storage drawer which provides storage space for sensors, manuals, spare connectors, cables, etc.
The cell infrastructure and test equipment control are connected via dedicated buses for fixed components of the test cell.
Harting connections to the Test Cell Management Control Unit, that manages the safety circuit integration, allows the racks to be connected into the test cell safety infrastructure.
REMOTE PATCH PANEL
To protect the equipment from being exposed to the harsh and potentially damaging conditions in the test cell the data acquisition and control rack is housed in an instrument room, therefore, we provided a local patch panel in the test cell environmental chamber to remotely connect to the main control rack via Harting and Deutsch connectors.
Test Cell Management Unit
TEST CELL MANAGEMENT UNIT
Due to the potentially dangerous nature of the tests being undertaken the test cell needs to offer full containment including safety management and galvanic isolation.
Based on an NI CompactRIO to provide deterministic, low-latency integration with the test Cell Control and Data Acquisition, The Test Cell Management Unit (TCMU) is responsible for managing the Test Cell System Safety and resource allocation.
The TCMU is responsible for monitoring the building automation systems (BAS) including fire detection/containment, full cell temperature, pressures and airflow control etc.
SAFETY SYSTEM INTEGRATION
Our consultants collaborated on the safety matrix and hazard analysis with Proventia, and Unico (who provided the Battery Cycler), to ensure all the elements of the safety circuit were fully integrated into the PLd rated system via the Test Cell Management Unit. (TCMU). The TCMU provides galvanic isolation and has dual channel inputs and outputs to prevent a single fault causing the loss of safety function as well as providing inputs into the safety system for software faults and alarms.
EVolution Control and Data Acquisition Software
To provide the level of flexibility required to accommodate potential new technologies and future requirements the software is based on a services orientated architecture that allows new sensors, or bespoke protocols via a simple low-cost, ‘plug-in’ upgrade.
It features a System Management layer for configuring the system, integration and tests, a deterministic real-time test engine for running models at 1kHz., and a device management layer that utilises device categories and validation to add new sensors.
SYSTEM MANAGEMENT INTERFACE
The dynamic management interface handles system configuration without the need for extensive low-level system setup, allowing immediate deployment of tests and scripts. It is designed to allow a high level of flexibility and usability, without the need for high-level programming knowledge or experience whilst permissions-based user-level access allows adaptable low-level configuration for advanced users.
USER LEVEL BASED ACCESS
In order to balance the need to make the platform accessible and easy to use for as many operators as possible, with varied levels of expertise, as well as safeguard personnel and equipment, the EVolution Control and Data Acquisition System can be configured to restrict users’ access so they are able to only utilise areas of the software that they have the expertise to use safely. For example, suggested access levels include Facility Manager, Test Engineer and Operator however the software itself operates with an access matrix that allows each individual login to have a custom set of access permissions as decided by the owner of the system. This allows for complete control and flexibility to build a user privilege system that is best suited to the particular needs.
The EVolution software links the access level of a user to the Microsoft account that they use to access the PC, the user also contains all their individual settings and configurations saved to their user area.
CONFIGURATION
The System Settings are a set of high-level settings that apply globally and provide the Proventia facility managers control over the main data storage areas of the system, as well as defining the IP addresses and network folders of key system addresses for the Test Cell management unit and DUT. It also allows them to set immutable administration limits to ensure that the system does not exceed safe parameters at any time. This is particularly useful when the ratings of two devices are different such that one can be run at a rate that would cause damage to another.
CHANNEL MAPPING WITH CALIBRATION AND ALARMING
When first configuring, the system allows specific physical channels to be assigned to in ports and out ports in models. Users can name channels appropriately for their specific test, and apply scaling and calibration to ensure that channels are giving results in the correct units for their sensors.
By utilising a system of device management, runtime alarming is built into the core framework and offers a flexible alarm strategy providing two types of alarms: Critical Cell Alarms and User Alarms.
Critical Alarms can only be configured by the system administrator and operate at two levels: 1) warning and 2) reach limit (which triggers the ESTOP action and procedure) and can be set for both high and low levels.
User Alarms also provide two levels of alarm: 1) warning and 2) stop test and can also be set for high and low levels.
ADVANCED WORKFLOWS
Advanced Workflows guide users through the required steps for loading models, channel assignments with scaling and calibration data, sensor databases, and test profile creation. A Profile Builder for generating new profiles means that the system can be configured for new tests without any programming. The advanced workflows guide the user through:
- Set up physical channels – calibration, sensor allocation, comms setup
- Add models
- Add calculated channels
- Map channels – I.e. model output to physical output
- Build configurable UIs
- Script tests
- Add alarms and setup background logging
- Deploy configuration to real-time hardware
DYNAMIC USER INTERFACE
The dynamic user interface provides widgets to allow the user to configure and save interface profiles specific to the requirements, in the test, without the need to restart a test thereby saving time.
The range of available widgets includes a series of fixed functionality widgets designed for control and indication of a specific area of the system, and a range of more generic widgets allowing any combination of data in the system to be viewed together.
Fixed widgets include Battery Control, Battery Simulator Control, DUT Temperature Control, Log Triggers, Safety System Feedback, Cell Services Feedback, Script Control (multiple widgets including Terminal, Script Editor, Parameters Manager). Generic Widgets include Graph, Table, Dial, LED, Buttons, XY Graph, Sliders, Model Input, Model Parameters.
RUNNING A TEST
The test interface offers multiple flexible features to support the user whilst running tests including time-saving in-test modifications whilst also maintaining critical safety monitoring:
- Hardware configuration is locked
- Automated tests are run through scripts
- Manual control can be taken through operating the user interface
- Analysis and calculations can be directly in the UI
- The primary control loop is running (including any specified models)
- User Interface can still be modified – channels can be allocated to UI ‘widgets’
- Data is streamed to the specified location, which can be a server.
HIGH-SPEED DETERMINISTIC MODELLING AND CONTROL. (HIL)
Based on NI’s VeriStand engine the system provides the ability to run many different types of complied models, ranging from MATLAB/Simulink, AVL Boost and Cruise, Technalia DynaCar, IPG CarMaker to simple models built in LabVIEW or pure C code.
INTUITIVE TEST SEQUENCING AND SCRIPTING VIA PYTHON SCRIPTING ENGINE
In addition to the Dynamic UI the system also offers a Python Scripting Engine which does not require high-level programming experience allowing the platform to be accessible to a wider range of operators. The integrated Python scripting tool allows new steps to be created for applying calculations to channels, importing new file formats and other requirements.
The fully-featured Python scripting engine allows users to write their own tests, and automate anything that they can do via the UI. The support library makes interaction with the test system super easy, with simple get/set calls, but also more powerful abstractions like “set_constant_current_mode()” (from the battery simulator). Full Python3.x support is provided with syntax checking and high-level parameter extraction (passing parameter sets into your script) and the ability to create and use your own favourite packages/libraries, allows advanced users to integrate analysis into the tests.
STANDARD TEST LIBRARY
As well as the ability to configure and deploy custom tests the system provides a library of industry-standard tests for characterisation, life and performance including (amongst others):
- Reference Performance Test (RPT)
- DC-IR
- Capacity
- Max Power
- Endurance (including discharge profiles)
- Fast charge
- Real-time execution of discharge pattern.
DATA-LOGGING
Background logging runs throughout the test. The user is able to set various different rates. All the channels, including those that are capable of higher speed datasets, are also available for shorter ‘burst’ logging, configurable during runtime. Log sets can also be set up prior to entering operational mode, and are triggered on the fly or by the scripting engine.
All data is synchronised, time-stamped and logged to an industry-standard, compact, efficient file format called TDMS. Data is partitioned and stored separately for each test situation and is controlled via permissions-based user-level access to ensure data integrity and confidentiality. The TDMS data is also compatible with the NI SystemLink Platform and DataFinder module that allows organisations to efficiently manage, search, access, and analyse measurement data and there are free plug-ins available for both MATLAB, Microsoft Excel and Python.
Outcome
The flexible system easily integrates with the Proventia test cell infrastructure and equipment, saving time and cost to deploy.
The software management layer provides safeguarding of equipment and people whilst providing easy to use workflows to guide both advanced system administrators and operators through the system configuration relevant to their level of expertise.
With the NI PXI platform and VeriStand engine at its heart, it is flexible to accommodate new technologies and future demands. New sensors, or bespoke protocols and be added via a simple low-cost, ‘plug-in’ upgrade.
- Cost-effective rapid deployment.
- Driving savings through innovation and utilisation of an extensible platform.
- Accelerating ROI on transformation initiatives
- Improved data management – access and use.
- Adaptable to accommodate new/changing technologies and test requirements.
- Enabling advances in engineering through design and build of innovative systems.
- Driving measurable productivity gains.
