ISO/TS 7637-4-2020 pdf free download.Road Vehicles – Electrical disturbance by conduction and coupling一 Part 4: Electrical transient conduction along shielded high voltage supply lines only.
4 Test methods
4.1 General
Various types of transients appear on the high voltage supply lines generated by the switching of various devices. Pulse A represents ringing caused by switching operations of high voltage semiconductors.
Pulse B represents sinusoidal waves generated by harmonics from the grid and revolutions from, for example, electric propulsion motors.
Methods for measuring the transient emission on shielded high- voltage supply lines and test methods for the immunity of devices against transients are given in this document. These tests, called “bench tests”, are performed in a laboratory.
The bench-test methods provide comparable and reproducible results between laboratories. They also give a test basis for the development of devices and systems and may be used during the production phase.
A bench-test method for the evaluation of the immunity of a device against supply-line transients may be performed by a test pulse generator. This might not cover all types of transients which can occur in a vehicle. Therefore, all described test pulses are typical pulses.
In special cases, It may be necessary to apply additional test pulses. However, some test pulses may be omitted, if a device, depending on Its function or Its connection, is not influenced by comparable transients in the vehicle. It is part of the vehicle manufacturer’s responsibility to define the test pulses required for a specific device.
There are two types of disturbances:
— Pulsed sinusoidal disturbances (Waveform A);
— Low frequency sinusoidal disturbances (Waveform B).
Pulsed sinusoidal disturbances on high voltage supply lines are caused by overshoots on square wave signals, e.g. produced by interaction of switching IGHTs in high voltage systems with parasitic capacities and inductivities of electrical engine systems, DC-DC-converters and any other kind of high voltage switching/commutation system. Pulsed sinusoidal disturbances on high voltage supply lines can be both common mode line-to-ground (HV+ or/and HV- to ground)] and differential mode (line-toline (HV+ to HV-)].
Test pulse A is used for testing high frequency oscillations, e.g. fast switching. Test pulse B is used to test equipment against transient voltages.
The device under test (DUT) shall be operated under typical conditions which cause the maximum disturbance and sensitivity during the measurement. This is the worst-case mode for every test and frequency step. Conditions shall be agreed between the vehicle manufacturer and the supplier and shall be documented in the test plan.
4.2 Standard test conditions
Standard test conditions according to Iso 7637-1 shall be used for test temperature and supply voltage (low voltage).
The high supply voltage UN can vary in a range from 60 V d.c. up to 1 500 V d.c. The used high voltage and its allowed tolerances of battery/generator in operation shall be agreed between vehicle manufacturer and supplier and shall be documented in the test plan.
4.3 Ground plane
The ground plane shall be made of 0,5 mm thick (minimum) copper, brass or galvanized steel.
Unless otherwise specified in the test plan, the minimum width of the ground plane shall be 1 000 mm, or underneath the entire setup width (excluding power supply and transient pulse generator) plus 200 mm, whichever is larger.
Unless otherwise specified in the test plan, the minimum length of the ground plane shall be 2 000 mm, or underneath the entire setup length (excluding power supply and transient pulse generator) plus.ISO/TS 7637-4 pdf download.