Unterschiede

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--- professoren_webseiten:rebholz:course_a_power_electronics [2025/05/05 18:25] – [Experiment] hrebholz
+++ professoren_webseiten:rebholz:course_a_power_electronics [2025/05/22 11:27] (aktuell) – [Adding Gate Driver] hrebholz
@@ Zeile 84: / Zeile 84: @@
 {{ :professoren_webseiten:rebholz:irs2890.png?200 |}}
 Gate drivers are often equipped with additional features. Our driver can detect overcurrents and if necessary, will turn off all MOSFETs for safety. Since overcurrents in a simulation tool will not damage your PC or notebook, you can ignore this feature in the simulation. Pull up the RFE output and connect ITRIP to ground. \\
-Datasheet: {{ :professoren_webseiten:rebholz:infineon-irs2890ds-ds-v01_00-en.pdf |}}
+Datasheet: {{ :professoren_webseiten:rebholz:infineon-irs2890ds-ds-v01_00-en.pdf |}} \\
+Download {{ :professoren_webseiten:rebholz:irs2890ds.zip |}}  the model file for LTSpice.
 <WRAP center round todo 80%>
@@ Zeile 483: / Zeile 484: @@
 ==== Experiment ====
-Lets try the full bridge with our DIY board.
+Lets try the full bridge with our DIY board. As a first step, we will look at the signals without the motor connected. Once we are sure that everything is correctly wired, we can operate the motor.\\
+**Hardware requirements**\\
+Make sure, that the driver circuit of the second half bridge V is assembled correctly. Check the PWM signals with the oscilloscope.\\
+**Software requirements**\\
+In order for current to flow through the motor, it is essential to activate the diagonal MOSFET pairs of the full bridge simultaneously—i.e., Q1 together with Q4 or Q2 together with Q3. Control laws typically refer to the high-side switches rather than the low-side ones. To ensure that Q4 is activated in sync with Q1 (or Q3 with Q2), we can apply a simple trick: operate bridge leg V with an inverted control signal relative to bridge leg U. This avoids the need for a 180° phase-shifted triangular carrier in PWM generation. In this case, the duty cycle for leg V becomes:
+Duty_V = 1 − Duty_U
+This inversion effectively ensures complementary switching of the corresponding low-side Mosfet, simplifying the implementation of the control scheme.\\
+Within Simulink just us a simple sum block:
+{{ :professoren_webseiten:rebholz:simulink_t-2.png?direct&400 |}}
+Additionally, using the microcontroller in combination with Simulink, we have the capability to implement a phase shift between PWM signals. For our purposes, the two relevant configurations are 0° and 180° phase shift. As described earlier, the mathematical trick used to compute the duty cycle for phase V by inverting the duty of phase U automatically results in a T/2 (i.e., 180°) phase-shifted switching pattern between the two bridge legs.
+If we wish to revert this automatic phase shift, we can do so by using a slider or parameter in Simulink to apply an additional 180° phase shift, effectively canceling out the original offset and returning to in-phase (0°) operation.
+{{ :professoren_webseiten:rebholz:simulink_phase-shift.png?direct&600 |}}
+<WRAP center round todo 80%>
+**Task 19a**
+Setup Simulink for full bridge operation. Measure the PWM Signals for Q1 and Q4 and check if you can apply synchronous and phase shifted PWM signals. Please do this with no load connected and without power supply.\\
+**Task 19b**\\
+Set the duty cycle to D = 0.5. Connect the load (DC motor) and the power supply. Consider how you can verify that your full bridge is operating correctly.
+</WRAP>
 <color #ffc90e>**Congratulations. Now you are ready and prepared for the exam!**</color>