Safe Measurements in High-Voltage Environments CSM GmbH Computer-Systeme-Messtechnik

Transcription

1 Safe Measurements in High-Voltage Environments < Computer-Systeme-Messtechnik Innovative Measurement and Data Technology

2 Why Measurements are Important! Development and optimization of drive concepts for electric and hybrid vehicles Enhancing efficiency and range Localizing the sources of power loss (heat) Increasing the efficiency of high-voltage batteries Optimizing the power electronics Increased pressure for cost optimization The topic safety plays an important role in this context! 2

3 Safety The term safety is derived from the Latin word sēcūritās and means without worry. Safety describes a condition which is free from unjustifiable risks or is regarded as non-dangerous It is, however, impossible to completely eliminate risks in complex systems, e.g. in high-voltage environments. It is for this reason that safety concepts are developed and implemented. Safety concepts entail preventive measures in order to make the occurrence of expectable and unexpectable events sufficiently improbable. 3

4 High-Voltage On-Board Unit A Complex System 4

5 High-Voltage On-Board Unit A Complex System Which is the upper voltage limit of SELV (Safety Extra-Low Voltage)? According to Low Voltage Directive 2014/ 35/ EU and safety standard DIN EN the following applies: Saf ety Ext r a-low Voltage Alternating Voltage Direct Volt age dry < 60 V wet < 35 V 5

6 High-Voltage On-Board Unit A Complex System Galvanic isolation between high-voltage on-board unit and 12 V on-board power supply and thus the car body. The measurement application must not undermine the vehicle s safety concept. High-Voltage Environment Safety Extra-Low Voltage (SELV) CAN bus data acquisition via software or data logger 6

7 Reinforced Isolation based on the example of an HV THMM 4 temperature measurement module Reinforced isolation Broken sensor detection Ref. V in + PT1000 V IN - Analog Low pass ADC 16 bit C1 Functional insulation Cold junction compensation per channel PT1000 at the NiCrNi - copper junction MC CAN Controller CAN Transceiver CAN BUS C4 Power supply Power + Power GND 7

8 Definition of Insulation according to Safety Standard DIN EN Basic insulation Insulation of dangerous live parts as basic protection Note: A basic insulation may also be used for functional purposes. Supplementary insulation Independent insulation which is used in addition to the basic insulation in order to protect against electrical shocks in the event of failure of the basic insulation. Double insulation Insulation consisting of the basic insulation and the supplementary insulation. Reinforced insulation Insulation providing protection against electrical shocks which is not inferior to the protection provided by double insulation. Note: REINFORCED INSULATION may consist of various layers which cannot be individually t ested as SUPPLEMENTARY INSULATION or BASIC INSULATION. 8

9 Requirements the Measurement System has to Meet Tested safety from the point of measurement to data acquisition An overall system that is electrically isolated and protected against accidental contact with life parts Suitable to be mounted close to the points of measurement Suitable for mobile applications and test bench applications Color coding that is suitable for high-voltage applications Precise and reliable measurement results Easy and safe operation 9

10 The Safety Concept Computer-Systeme-Messtechnik

11 Measurement Technology Safety Concept Type approval test of the entire system (measurement hardware and sensor cables) performed by an accredited test laboratory Safety DIN EN and DIN EN EMC (CE) DIN EN Type approval test of measurement hardware performed by an accredited test laboratory IP protection class DIN EN 60529:2000 Change of temperature DIN EN Vibration DIN EN Rough handling DIN EN Shock DIN EN

12 Measurement Technology Safety Concept Type approval test of high-voltage cables Bending VDE III ±90 and in accordance with DIN EN Routine test of measurement hardware (incl. testing certificate) Safety in accordance with DIN EN :2010, F.4 Routine test of high-voltage cables Safety in accordance with DIN EN Routine test of pre-assembled high-voltage cables (incl. testing certificate) Safety in ball pit according to a test, defined by the VDE (Association for Electrical, Electronic and Information Technologies) 12

13 Measurement Technology Safety Concept Test specification: Test voltage typically three times higher than insulation voltage (e.g V) Typical rise time: 5 s Typical hold time: 5 s Required test sequence for all inputs: All measurement channels II SELV (CAN, power supply, housing) Measurement channels 2,3,4,5,6,7,8 II Measurement channel 1 Measurement channels 1,3,4,5,6,7,8 II Measurement channel 2 Measurement channels 1,2,4,5,6,7,8 II Measurement channel 3 Measurement channels 1,2,3,5,6,7,8 II Measurement channel 4 Measurement channels 1,2,3,4,6,7,8 II Measurement channel 5 Measurement channels 1,2,3,4,5,7,8 II Measurement channel 6 Measurement channels 1,2,3,4,5,6,8 II Measurement channel 7 Example for a testing certificate Computer-Systeme-Messtechnik

14 Measurement Technology Safety Concept An appropriate safety concept contains also handling during lifetime Recommended safety testing interval for isolation: at least every 12 months Additional isolation test if there is reason to assume that the isolation may have been damaged (e.g. due to overvoltage, high temperature, high mechanical stress, etc.) Isolation testing is offered typically from the hardware suppliers themselves or with in-house test stands Computer-Systeme-Messtechnik

15 w High-Voltage-Safe from the Sensor to the Point of Data Acquisition! 15

16 Temperature Measurement Chain Example of Application: Power Electronics Conventional temperature measurement chain No contact protection due to non-isolated contacts Power electronics No strain relief Not water-proof Insufficient insulation no high-voltage safety! standard measurement module 16

17 Temperature Measurement Chain Example of Application: Power Electronics High voltage-safe temperature measurement chain Double-insulated, multi-wire cable, 4 channels Wat er-proof connection High-voltage measurement device Power electronics Completely isolated plastic connector CAN & Supply Computer-Systeme-Messtechnik Tit el