Archive for June, 2011

With its hardware-in-the-loop (HIL) systems being a de-facto standard for automotive OEMs, it was an obvious next step for dSPACE to provide an extension to simulate dynamic simulation of battery cells and packs for comprehensive testing of embedded systems in EVs and HEVs.

As a result, a battery model for simulating high-voltage rechargeable batteries is the latest addition to dSPACE Automotive Simulation Models (ASM) simulation package. The model is designed to virtualize the rechargeable lithium-ion, nickel-metal hydride (Ni-MH) and lead- acid batteries used for electric propulsion in vehicle drivetrains.

“Our customers have recognized the limitations imposed by alternatives and have shown a keen interest in the adoption of the dSPACE solution to complement their HIL [hardware-in-the-loop] test setups for Battery Management System (BMS) software validation and verification,” says Mahendra Muli, New Business Development Manager for dSPACE Inc.

Developed in parallel to the increasing adoption of Li-Ion batteries, a comparable alternative to simulate batteries did not exist prior to dSPACE solution. Some development and testing happened with static and/or limited capacity cell simulation with programmable analog voltage sources, or in some cases, real cells.

“With these setups, it is not possible to accurately re-create test conditions, validate state-of-charge (SOC) detection algorithms that require a precise, high-resolution analog cell voltage simulation and exercise diagnostics software by creating fault conditions,” says Muli.

The dSpace model facilitates function development for the BMS and also the testing of close-to-production electronic control units (ECUs). In addition to supporting the elementary functions of current battery management systems, such as cell balancing, the new ASM multicell battery model simulates every single battery cell to represent the cell-specific charges, voltages and currents. Physical parameters such as internal resistance, diffusion and double-layer capacities can be defined for each cell.

Flash memory has been the mainstay of automotive control systems for many years but two new products may make a dent in future Flash memory design-ins.

Texas Instruments recently introduced the industry’s first microcontroller (MCU) with embedded FRAM (Ferroelectric Random Access Memory). According to Morry Marshall, director strategic technologies and automotive specialist at Semico Research, a semiconductor market research firm, FRAM combines the best characteristics of SRAM, DRAM and Flash. It has nearly SRAM speed, is low-cost like DRAM and is non-volatile like Flash. In addition, endurance (the number erasure possible before failure) is not an issue with FRAM, as it is with Flash memory.

“This chip is aimed at industrial markets, but there is no reason it could not be used in automotive markets,” says Marshall. “ It is a low memory-density part, initially 4KB, 8KB and 16KB, but this enough memory for many control applications.”

Also called F-RAM and FeRAM, automakers including Mercedes, GM, BMW, Ford, Porsche, and others, already use FRAM in their vehicles but in standalone form.

Another milestone announcement came earlier this year from Everspin Technology, a pioneer in magnetoresistive random access memory or MRAM. Everspin added AEC-Q100 automotive temperature products to its MRAM portfolio, including x 8, x 16 and serial SPI interfaces. MRAM also has significant advantages over Flash memory including fast and unlimited read/write endurance coupled with 20-year data retention.

The new MRAM products operate over an extended temperature range (-40ºC to 125ºC) and provide extreme reliability. Because MRAM is always non-volatile, power loss after writes to MRAM does not affect data integrity. The temperature range and high reliability make these products a natural for automotive applications including this in harsh mounting locations for applications including engine and transmission control. BMW has already chosen MRAM technology to solve a data retention problem in its Motorrad Motorsport engine control unit.

“As far as MRAM goes, there is opportunity here as some new designs are replacing SRAM with MRAM,” says Susie Inouye, research director and principal analyst at databeans, Inc., a market research firm, “Everspin has been targeting automotive with this newer technology because of the relationship with Freescale [Semiconductor], one of the largest component suppliers to the automotive segment,” she says.

Databeans estimate for embedded memory in automotive for 2010 was $2.5 billion and is expected to increase by 10 percent in 2011.

We’ll just have to wait and see how future automotive applications take advantage of these new memory alternatives to Flash.