Comparison of SCR and IGBT Rectifiers in Electropolishing Applications

2026.01.26

Electropolishing, as a key process in modern metal surface treatment, places increasingly stringent demands on the performance of DC power supplies. As the core component of an electropolishing system, the rectifier's technology selection directly impacts polishing quality, energy consumption, and production efficiency.

I. SCR Rectifier Technology Principles and Application Characteristics in Electropolishing

1.1 Advantages in Electropolishing

High Technological Maturity: After decades of development, SCR technology is stable and reliable, with a well-established maintenance system.
Low Initial Investment Cost: Relatively low device and system costs, suitable for projects with limited budgets.
Extensive Experience in High-Power Applications: Abundant application cases in ultra-high-power (MW-level) scenarios.

1.2 Limitations

Slow Response Speed: Second-level response time is insufficient to meet the rapid adjustment requirements of modern electropolishing processes.
High Output Ripple: High DC output ripple content requires additional high-capacity filters.
Harmonic Pollution Serious: Phase control generates a large number of harmonics, causing pollution to the power grid. Low efficiency under partial load: Efficiency drops significantly under low load. Large size: The volume and weight of the IGBT solution are 5-10 times that of the IGBT solution for the same power.

II. IGBT rectifier technology principle and its application advantages in electropolishing

2.1 Core advantages

Excellent control performance
Significant energy saving effect
Compact structural design
Intelligent function

III. Technical requirements of power supply for electropolishing

process Electropolishing achieves surface smoothing by selectively dissolving the workpiece as the anode in a specific electrolyte. This process has unique power supply requirements:

Voltage stability: The operating voltage is typically 8-10V; voltages below 6V will result in slow polishing speed and insufficient gloss.
Low ripple requirement: Low electrical signal ripple ensures a uniform and stable dissolution process, improving surface quality.
Fast response capability: Microsecond-level system response to adapt to real-time adjustments of process parameters.
High-precision control: Voltage/current regulation accuracy must reach two decimal places (0.01V/0.001A level).
Safety protection: Multiple protection functions including overvoltage, overheat, and short circuit are required.

IV. Comprehensive comparison of SCR and IGBT rectifiers in electropolishing applications

Comparison Dimensions	SCR	IGBT Rectifier	Impact of electropolishing applications
Control Precision	±2-3%	±0.5-1%	IGBT significantly improve polishing uniformity.
Response Speed	Second-level	Millisecond/microsecond level	IGBT adapt to rapid process changes
Output Ripple	5-10%（No filtering）	<1%	IGBT reduce surface defects
Conversion Efficiency	85-90%	>95%	IGBT save 10-30% energy
Power Factor	0.8-0.9	>0.95	IGBT reduce grid load
Harmonic Content	15-25%	<3%	IGBT require no harmonic mitigation
Size and Weight	Large (equivalent power)	Small (only 1/5 to 1/10 of SCR)	IGBT save factory space
Maintenance Cost	Lower	Extremely low (modular design)	IGBT reduce downtime
Initial Investment	Low	Higher	SCR offer significant short-term cost advantages
Level of Intelligence	Basic	Highly digitized	IGBT support smart manufacturing

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