Tuesday, February 07, 2017

Reliability in Axial and Radial Plastic Capacitors

The Axial capacitors like Metalized Polypropylene MPP are more reliable in comparison of their radial counterparts of same voltage rating.

Also note 440V AC Continuous rating reads and translates differently than 630V DC Max. Overrating is an important step in reliability for engineers.

High Energy Circuits

Radial plastic caps, in mass production, due to various inconsistencies in production or quality measurement, are not recommended for high voltage unless its is a Manufacturer known for long term reliability and quality track record.

Reliability in Axial and Radial Plastic Capacitors

The radial caps when being wound, stretches the film/dielectric or weakens the dielectric at some areas as the turn is sharp, top/bot. This is possible unless the winding machine relaxes strain around the turns. In a Axial that may not be a problem as the film has more uniform stretch. The other reason  could be that the Film is wrapped a little on corners or compressed on epoxy impregnation. It could also be low quality non-uniform PP material.

Power Electronics & Solar Energy

Components Manufacturers have to spruce up a Raw-Material and Component Quality, not by red-tape but by actually improving the manufacturing and procurement processes, as the quantities involved are huge.

Monday, February 06, 2017

Induction Heating - Cooker Project

Single plate induction cooker demonstration board  Uses ST7LITE09 and STGW40NC60WD (40 A, W series).

The design is entirely controlled by a simple ST7FLITE09Y0 8-bit microcontroller, which  provides the PWM driving signals, communicates information to the user interface, and  drives the fan and relay control to the plate feedback.

With Single Voltage Flash Memory, Data Eeprom, Adc, Timers, Spi Active - ST7LITE09Y0 8-Bit Mcu

Induction Heating - Cooker Project

A single plate induction cooker with the ST7FLITE09Y0  PDF - Excerpt From Application Note above AN2383 Application note -

Put simply, an induction cooking element (what on a gas stove would be called a "burner") is a special kind of transformer. When a good-sized piece of magnetically conducting material such as, for example, a cast-iron frying pan, is placed in the magnetic field created by the cooking element, the field transfers ("induces") energy into the metal. That transferred energy causes the metal - the cooking vessel - to become hot.

By controlling the intensity of the magnetic field, we can control the amount of heat being generated in the cooking vessel and we can change that amount instantaneously.

Induction cooking functions based on the principle of the series L-C resonant circuit, where the inductance L is the cooking element itself. By changing the switching frequency of the high voltage half-bridge driver, the alternating current flowing through the cooking element changes its value. The intensity of the magnetic field and therefore the heating energy can be controlled this way.

Induction Cooker - STMicro AN2383

The +325 V DC link voltage is applied through a filter to the upper-side IGBT only when the safety relay is closed and the system is on. Components inside the dotted rectangle are the core part of the power stage: the L-C resonant tank is obtained by the plate (represented in the schematic by a spiral) and the capacitors on the left side. The resonant capacitor has been divided in two identical capacitors, so that the amount of current flowing through each capacitor is reduced by half, while the voltage to the capacitors remains the same.

Induction heating is a non-contact heating process - Richie's Tesla Coil Web Page

Thursday, February 02, 2017

Ricoh Electronic Devices - Smart Energy

Design and Manufacture semiconductor electronic devices, specialized design service for electronic devices and manufacturing service for such products.

Ricoh Electronic Devices - Smart Energy

Product line include - Power Management ICs, Real-time clock ICs, PC Interface and Communication LSI / Image Processing LSI.

Power Management ICs - DC/DC Converters, Battery Management, Watchdog Timer(W.D.T.) and Voltage Regulators.

The R1218x Series are PWM control type step-up DC/DC converter ICs with low supply current. It is fully dedicated to drive White LED with constant current.

R1218x Series - RICOH

Constant current can be set with an external resistance value. Dimming control is possible by PWM signal for CE pin. Feedback voltage is 0.2V, therefore power loss by current setting resistor is small and efficiency is good.

Ricoh Electronic Devices Company, Ltd.
13-1 Himemuro-cho, Ikeda City, Osaka 563-8501, JAPAN