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PWM Measurement Solution

Capturing of PWM signals

The DS5202 PWM Solution combined with a simulation model lets you measure the signals of up to 4 electric machines with up to 8 power switch control signals each, for example, IGBTs (insulated-gate bipolar transistors).

Overview

dSPACE offers you the PWM Measurement Solution, which is based on the DS5202 FPGA (field programmable gate array) Base Board. It is specially designed for high-precision digital capturing of three-phase PWM signals such as those typically used for controlling a three-phase AC electric motor.

Efficient testing of electronic control units (ECUs) for electric machines requires fast measurement and analysis of several closely associated signals. The challenge is to capture these signals with a very short sample time, e.g., <20 µs.

 

Key Benefits

The DS5202 PWM Measurement Solution combined with a simulation model lets you measure the signals of up to 4 electric machines with up to 8 power switch control signals each, for example, IGBTs (insulated-gate bipolar transistors). The combined signals of up to 4 inverter legs can be evaluated for verifying the ECU’s functions. For example, if the dead time does not reach the predefined minimum, an error flag is generated and an interrupt is triggered. To measure the gate time, there are three operating modes to choose from: software polling, external interrupt source, and internal pulse center interrupt source, meaning clock generation based on the measured PWM signals. If you do not have access to the ECU’s clock rate, PWM-based clock generation is the most suitable way of avoiding beat effects in the simulation.

Parameter Specification
Timing resolution
  • 25 ns
Digital input Number of channels
Input voltage range
Two adjustable threshold values Input resistance Resolution
  • 32
  • 0 ... +15 V
  • 2.5 or 7.5 V
  • 10 kΩ n 25 ns ... 400 ns (adjustable)
Digital output Number of channels
Output voltage range Used for
  • 4 (shared with digital inputs)
  • 0 ... +5 V n PWM center trigger generation
Frequency range
  • 39 Hz to 40 MHz

A typical use case is a hardware-in-the-loop (HIL) simulation, where the electric motor including the electronic power stage is simulated by means of the dSPACE modular real-time hardware. Simulation models like dSPACE’s ASM Electric Components Library are used for simulating electric components. The gate driver signals (typically PWM signals) coming from a controller are measured by the DS5202 PWM Measurement Solution. The calculated motor current signals are sent back to the controller by means of analog voltage signals.

Informations de base