Drive System Design (DSD), a company specialising in the rapid engineering and development of electrified propulsion systems and associated technologies, has developed a new method and strategic plan to better support clients in designing and developing electric motors and inverters that best fit their needs.
DSD has observed that many motor and inverter manufacturers, as well as system integrators, often take their electrification development programmes directly to a dynamometer (dyno) test cell, only to uncover critical issues that need to be overcome, which can stop the programme in its tracks. With this seemingly direct approach, months are added to the project timelines in order to find and fix unforeseen integration issues.
To help save its customers months of time and tens of thousands of dollars, while ensuring a more robust, reliable concept before ever touching a dyno test cell, DSD has created a new Motor Control Development Method consisting of four key phases that it will now implement for most electric motor and inverter development projects.
“There is immense benefit in minimising project risk by following our four-phase approach. Too often, a push to be first-to-market ends up incurring more cost and time,” said Murray Edington, head of electrified powertrain, Drive System Design. “Ultimately, this approach will enable our customers to be first-time capable, meaning they will be set up for a successful pairing of the inverter and motor once the product reaches the dyno test cell. This will speed up final validation and significantly reduce the risk of needing extra hardware iterations, saving our customers both time and money while delivering a more high-quality product.”
Below is a look at DSD’s four-phase approach, with many companies currently skipping from Phase 1 to Phase 4:
- Phase 1 – Concept evaluation and design with advanced co-simulation. During this phase, control algorithms, finite element analysis (FEA) motor models and the power electronics model are designed and developed. A closed loop advanced co-simulation of the entire system will then be performed. By driving the system model with more representative control signals rather than simpler idealised inputs, early-stage identification of electromagnetic challenges along with accurate early-stage data for larger system analysis activities like noise, vibration and harshness (NVH), can be achieved.
- Phase 2 – Detailed design and validation with Control Hardware-in-the-Loop (C-HIL). DSD will utilise inverter control board hardware with deployed software and a real-time simulation of the motor model. The C-HIL hardware emulates motor behaviour and sensor feedback such that a large proportion of the software and low voltage hardware validation can be performed. This phase allows for development and validation of safety monitoring and fault handling without risking hardware failures. Software development time is reduced for subsequent phases through bug fixing at this stage.
- Phase 3 – Component level testing with Power Hardware-in-the-Loop (P-HIL). At this stage, a large proportion of the inverter validation will take place by running full power through the inverter with deployed software and utilising a battery and a high voltage motor emulator. The motor is modelled but real current and power is being pushed through real inverter hardware to validate its power stage and control. When a novel motor design is in the manufacturing stage, DSD can leverage its open platform inverter, to quickly and efficiently develop, calibrate and validate the motor controls for that application in this phase of testing.
- Phase 4 – System level testing and validation on a dyno test cell. The motor will enter the dyno test cell at this stage as a final system validation and characterisation utilising inverter and motor hardware as well as the battery emulator. Going through the previous stages ensures this phase will be as short, cost effective and efficient as possible.
As an initial investment to fulfil its new motor development strategy, DSD has acquired a C-HIL rig, which will be housed at its technical centre in Farmington Hills, Michigan. Additionally, DSD will be partnering with the Auburn Hills-based rig supplier to have access to their P-HIL rig and motor emulator, with plans to invest in one of its own next year.
“Real-world issues can now be predicted or reproduced and solved prior to – or in parallel with – dyno or test cell work,” said Brentnall. “This new approach and equipment will further advance DSD’s turnkey capability of delivering motor controls and electrification across a range of markets.”
Through DSD’s method, customers will now be able to better optimise their time, as a large proportion of the inverter software and hardware can be developed and validated through Phase 2 and 3 while the motor hardware is being made. Further, the method is adaptable for various vehicle types, including automotive, trucking, off-highway, defence and aerospace.
With the immense value of taking a more comprehensive approach to motor and inverter design and development like DSD’s, the company predicts that most companies tackling similar projects, including key competitors, will adopt a similar approach in the next five to 10 years.