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Non-Destructive Testing
MES is a full service provider of field and laboratory Non-Destructive Testing (NDT) techniques.. NDT provides an excellent means of balancing quality control, cost effectiveness and time.
Our nondestructive testing inspectors are certified to ASNT SNT-TC-1A. Level III certifications from the American Society for Nondestructive Testing (ASNT) include: Radiography (RT), Ultrasound (UT), Magnetic Particle (MT), Eddy Current (ET) and Penetrant Testing (PT). Our Level III certifications also include, Navy Nuclear NDT Examiner Certifications in: NAVSEA 250-1500-1 MT, PT, RT, UT, VT, and MIL-STD-2132 MT, PT, RT, UT to meet your industry requirements. All results are evaluated by our certified NDT Level 2 and Level 3 technicians.
MT – Magnetic Particle Testing
Magnetic particle testing is performed by inducing a magnetic field in a ferromagnetic material and then dusting the surface with iron particles. The surface will induce magnetic poles and distort the magnetic field in such a way that the iron particles are attracted and concentrated making defects on the surface of the material visible.
PT – Dye Penetrant Testing
Dye penetrant testing is utilized to locate discontinuities open to the material surface. A highly penetrating dye on the surface enters discontinuities after a sufficient penetration time due to capillary action, and after removing the excess dye with a developing agent, the defects on the surface will be visible.
RT – Radiographic Testing
Radiographic testing is used to detect internal defects in castings, welds or forgings by exposure to x-ray or gamma ray radiation. Defects are detected by differences in radiation absorption in the material as seen on a shadow graph displayed on photographic film.
UT – Ultrasonic Testing
This test method uses high frequency sound waves to conduct examinations and take measurements. Ultrasonic inspection can be used for flaw detection/evaluation, dimensional measurements, material characterization, flaw sizing and more. Produces a 100% volumetric inspection of the material.
ET – Eddy Current Testing
Eddy current testing is used to detect surface and near-surface irregularities in ferrous and non-ferrous materials by inducing an eddy current field in the part under test.
VT – Visual Testing / Visual Inspection
Visual testing/inspection is a time and money efficient option to secure proper system or product quality.
Other NDT Services
- Coating Characterization
- Compositional Analysis (EDS)
- Profilometer
- Replication metallographic analysis
- Strain Gauge
- Chemical Analysis
- Corrosion Testing Lab
- Failure Analysis Lab
- Mechanical Testing Lab
- Metallurgical Lab Services
- Non-Destructive Testing
- Other Testing
- Surface Analysis Lab
- Weld Inspection ServicesCeraLink offers many benefits for DC link circuits of inverters for e-mobility.
The CeraLink™ capacitors offers many benefits for stabilizing and filtering the DC link circuits of power inverters – particularly in comparison with conventional capacitor technologies. Developers of topologies with new fast-switching IGBT modules will profit from this innovation.
The power semiconductor switches used in power supplies and inverters are determined by two technologies, namely MOSFETs and IGBTs. MOSFETs can be operated at relatively high switching frequencies significantly above 30 kHz, but unlike IGBTs, they have a very large chip surface area. A new generation of IGBT modules from Infineon Technologies operates at frequencies of up to 100 kHz. Linebased and turn-off losses are of about the same magnitude in both systems. Fast IGBTs, whose manufacturing complexity is significantly lower and chip areas are often smaller than superjunction MOSFETs, are the basis of an IGBT3 technology with high switching frequencies and an excellent price-performance ratio.
Fast-switching systems require circuit designs with minimized ESR and ESL values. Accordingly, the passive components – inductors, but especially capacitors – must also keep pace with the high switching frequencies. These in turn permit more compact and lightweight passive components to be used, producing lower losses and increasing efficiency.
Capacitors are at the focus of these developments. They must combine high switching frequencies with low ESL and ESR values as well as an extremely compact design. Conventional capacitor technologies are only partially able to meet these requirements. The EPCOS CeraLink represents a completely new approach: This advanced component is a ceramic multilayer ripple-current suppressor, also known as a link circuit or DC link capacitor; moreover, it functions as a snubber.
The EPCOS CeraLink was developed in the company’s Competence Center for Ceramic Components in Deutschlandsberg, Austria. The know-how that formed the basis for this advanced component was gained, among others, over many years in the volume manufacture of piezo actuators. The EPCOS CeraLink offers the advantages of ceramic capacitors without their unfavorable characteristics. The patented multilayer component that is based on antiferroelectric ceramic material with special copper internal electrodes allows both standard IGBTs and the new high-speed types with significantly higher switching frequencies to be used even more economically. This naturally also applies to circuits with corresponding superjunction MOSFETs. The innovative CeraLink combines high capacitance per volume with lowest ESL and ESR values, which thus enables significant improvements in efficiency, reliability and space requirement for future IGBT and MOSFET inverter designs. Moreover, CeraLink is also available in a low-profile SMD design, making it suitable as a snubber solution for integration in power modules. The EPCOS CeraLink components were adapted and continuously optimized for the first designs of special IGBT modules in close cooperation with Infineon Technologies, the market leader in IGBTs. This allowed the best results to be achieved in terms of performance and energy efficiency. For both the EASY automotive series from Infineon Technologies and the corresponding types in industrial applications, all the relevant capacitor parameters and properties were optimized towards more economy and efficiency (Table 1).
The first designs of an on-board inverter, the Infineon EASYKIT DCDC, were based on existing OEM specifications for rated voltages of about 400 V DC on the high-voltage side.
The EPCOS CeraLink is currently available in several designs. Its capacitance range extends from 1 μF to 100 μF at rated voltages of 400 V DC and 800 V DC. The various terminal designs are shown in Figure 1. The SMD versions (LP and SMD) are designed for direct integration in semiconductor power modules in view of the restricted space available (Figure 1).
They can be soldered, bonded or sintered.
In close cooperation with EPCOS, Infineon Technologies has developed an HV/LV DCDC demo board with an output of 2.7 kW. The requirements included a high-voltage input range from 200 V DC to 400 V DC – depending on the HV battery used – and a low-voltage output range from 8 V DC to 16 V DC that is typically standard in automobile electronics systems. Furthermore, the demo board had to cover a current range of up to 200 A DC.
Various types of circuit topologies are available on the DC-DC converter market. However, the most widely used is the fullbridge circuit with a zero-voltage transition (ZVT) based on MOSFET transistors. Infineon Technologies has redesigned these circuits with various EPCOS components and adapted them to its EASY series of fastswitching IGBTs (Figure 2).
They employ a large number of diverse EPCOS and TDK components (Table 2).
The EPCOS CeraLink combines high capacitance per volume, low ESL and ESR values, as well as a minimum leakage current, and thus satisfies all the requirements of high-speed IGBT modules or MOSFETs. This system configuration also permits high current change rates (di/dt) of up to 10 kA/μs to be controlled. Despite these extremely high potential rates, the generated voltage peaks (V = L * di/dt) are extremely low thanks to the low ESL of the CeraLink.
Parasitic inductances are not only caused by the capacitor. Noticeable stray inductances occur in a normal system configuration for several reasons, including the contacting inside the IGBT module and the feed line to the capacitor. The EPCOS CeraLink allows the values for the feed line to be dramatically reduced to the same extent as the values for the capacitor itself, thanks to its compact design. The compact link to the IGBT module simultaneously attenuates its overvoltages, and a snubber capacitor is usually not necessary. Figure 3 shows the voltage curve at turn-off of the IGBTs with and without an EPCOS CeraLink. The voltage rise is thus only minimal and is within the safe range for the IGBTs. A switching frequency of 100 kHz is used in this case, meaning a ripple current frequency of 200 kHz for the capacitor. Figure 4 shows the impedance and ESR curves as a function of the frequency.
Although the capacitance of the EPCOS CeraLink is usually sufficient for pure DC-DC applications, it may be too low for motor operation, for example. This can be remedied by connecting aluminum electrolytic or film capacitors in parallel, as their high capacitance carries the low-frequency current component. The EPCOS CeraLink then handles the high-frequency component, including the snubber component.
Samples are available to fit