🔍 Key Concepts

• 3-phase bridge rectifier vs. inverter – which one changes AC to DC, and which one changes DC back to AC? • DC link in a frequency converter – what is usually placed between a rectifier and an inverter and why? • Inductor behavior in DC circuits – how does an inductor affect ripple and current changes coming from a rectifier output?

💭 Think About

• Look carefully at the symbol used for the DC link in the illustration: what type of component does that symbol represent, and what is its usual function in power electronics? • Ask yourself: after the 3‑phase bridge rectifier, is the power already DC or still AC? How does that help you rule out some choices? • Which device in the drawing is responsible for gate trigger pulses and frequency control – is it the DC link, or another labeled component?

✅ Before You Answer

• Verify which block in the diagram is explicitly labeled as the 3‑phase bridge rectifier and what its job is. • Note that the DC link symbol looks like a coil/inductor, placed between the rectifier and the controlled inverter – consider what problem it would solve there (think: smoothing). • Confirm which component would logically handle gate triggering and output frequency control – compare that with the wording of choice (D).