Design and Application of Ripple Suppression Circuits for Low-Ripple High Voltage Power Supplies
In precision instrumentation and medical imaging systems, the output ripple of high-voltage (HV) power supplies critically impacts signal-to-noise ratios and measurement accuracy. This paper systematically explores innovative ripple suppression technologies based on topology optimization and multi-modal control strategies.
1. Ripple Generation Mechanisms
HV power supply ripples originate from three coupled factors: (1) transient spikes during power device switching (up to MHz frequencies); (2) resonance effects from transformer leakage inductance and parasitic capacitance; (3) interstage coupling interference in multi-stage boost architectures. Unoptimized 30kV/5A circuits exhibit peak-to-peak ripples up to 3%, while medical CT systems require ≤0.05% ripple coefficients.
2. Multi-Dimensional Suppression Technologies
Topology Optimization
Interleaved LLC resonant converters with 180° phase shift cancel odd harmonics, achieving >40dB fundamental ripple attenuation. Distributed π-filter networks embedded in each boost stage block ripple propagation, reducing 20kV/10mA supply ripple to 0.02%.
Dynamic Compensation
A hybrid feedforward-feedback system combines high-frequency current transformer sampling with improved sliding mode control, achieving 50μs recovery time under load transients.
Parasitic Parameter Control
Multi-physics simulations optimize transformer parameters, reducing leakage inductance to <0.5μH through layered winding. Electromagnetic isolation layouts maintain ≥8mm spacing between critical traces, lowering ground plane impedance to 2mΩ.
3. Circuit Design Innovations
Composite Filtering
Three-stage filtering includes: (1) Active EMI filters suppressing 0.15-30MHz conducted noise; (2) Ferrite bead-ceramic capacitor arrays absorbing ns-level spikes; (3) Gas discharge tubes and MOVs for kV surge protection.
Digital Monitoring
16-bit ADC modules with FFT analysis achieve 10mVpp resolution. Embedded systems dynamically adjust PWM dead time based on identified ripple spectra.
Thermal-Electronic Co-Design
3D liquid cooling limits junction temperature fluctuations to ±3℃, while temperature compensation circuits restrict thermal-induced drift to 0.005%/℃. Aluminum nitride substrates reduce thermal resistance to 0.15K/W.
4. Application Cases
In X-ray tube supplies, optimized circuits reduce current ripple from ±1.2% to ±0.08%, enhancing imaging resolution to 25lp/mm with adaptive spectral filtering. Semiconductor ion implanters achieve 99.99% beam stability, significantly lowering wafer defect rates.
5. Future Directions
AI-driven self-tuning systems will leverage online ripple feature learning. Ferrite metamaterials enable 60dB attenuation of GHz ripples. Digital twin integration will facilitate predictive maintenance throughout the system lifecycle.