Antiferroelectric Ceramic Capacitor Reduces Self-Heating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Capacitors in high-power applications, such as AC/DC converters for motor drives, face limitations due to parasitic properties from semiconductor elements, leading to overheating and reduced service life, and existing ceramic materials suffer from capacity degradation at high voltages and self-heating issues, making them unsuitable for close proximity to semiconductors.
Innovation Solution
An antiferroelectric ceramic material with a specific formula [Pb(1-r)(Ba x Sr y Ca z )r](1-1.5a-1.5b-0.5c)(La a Nd b)A c is developed, where A is a monovalent ion, allowing for reduced self-heating by adjusting lattice dynamics and using copper internal electrodes, which maintains high performance and reduces loss angles by up to 80%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional ceramic materials are used in capacitors, then high capacitance can be achieved, but self-heating occurs and service life is reduced
Solution Approach 1:
The patent changes the chemical composition parameters of the ceramic material by incorporating specific amounts of barium (x), strontium (y), and calcium (z) into the lead zirconate titanate structure, where x + y + z = 0.01 to 0.20. This compositional parameter change modifies the dielectric properties and reduces self-heating while maintaining high capacitance
Solution Approach 2:
The patent creates a composite ceramic material by combining multiple elements (Pb, Ba, Sr, Ca, La, Nd, Zr, Ti, and monovalent ions) into a single ceramic system with formula [Pb(1-r)(Ba x Sr y Ca z )r](1-1.5a-1.5b-0.5c)(La a Nd b)A c (Zr 1-d Ti d)O 3. This composite approach allows synergistic effects that reduce self-heating while preserving high capacitance
2Volume of moving object
If capacitors are placed close to semiconductors to save space, then miniaturization is achieved, but temperature increases due to heat from semiconductors
Solution Approach 1:
The patent modifies the thermal parameters of the ceramic material through compositional changes, specifically incorporating barium, strontium, and calcium which alter the thermal conductivity and heat dissipation characteristics, allowing the capacitor to operate at higher temperatures without degradation
3Productivity
If high currents are switched quickly, then power efficiency is improved, but high overvoltages occur that can destroy semiconductors
Solution Approach 1:
The patent changes the dielectric parameters of the ceramic material, specifically the dielectric constant and loss tangent, through compositional modification. The optimized composition provides faster charge/discharge capability while limiting voltage spikes, enabling high-speed switching with reduced overvoltage stress
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The ceramic material significantly reduces self-heating and maintains high performance, enabling capacitors to be placed closer to semiconductors, optimizing space and minimizing electromagnetic radiation, while using cost-effective copper electrodes and maintaining high dielectric constants.
Implementation Method 1
the very high dielectric constants and very low loss angles which are achievable with antiferroelectric materials
Implementation Method 2
significantly reduces self-heating and maintains high performance, enabling capacitors to be placed closer to semiconductors
Data Source
AI summary
The invention relates to a ceramic material for capacitors. In order to achieve reduced self-heating on assembly of the material into multilayer capacitors with antiferroelectric properties and a high dielectric constant, a ceramic material of formula [Pb(1-r)(BaxSryCaz)r](1-1 5a-1,5b-0,5c)(XaYb)Ac(Zr1-dTid)O3 is proposed, where X and Y both represent a rare metal earth selected from the group consisting of La, Nd, Y, Eu, Gd, Tb, Dy, Ho, Er and/or Yb; where A represents a monovalent ion; x + y + z = 1; x and/or y and/or z > 0; 0 < r < 0.3; 0 < d < 1; 0 < a < 0.2; 0 < b < 0.2; 0 < c < 0.2.