GE&EL+ Regenerative Load

In switched power converters, as the converters from Cinergia, the power semiconductors work in two states: completely OFF (zero current) or entirely ON (near zero voltage). While transiting from one state to the other, the voltages and currents do not change immediately and therefore are both non-zero during some short time. This current-voltage crossover generates power losses in the semiconductor at each switching cycle, which happens at 15 kHz.

The main benefit of SiC MOSFETs is the faster switching time, thus reducing the current-voltage crossover duration, and therefore reducing the losses at each commutation.

As the losses at each commutation are reduced, the switching frequency of the SiC MOSFET can be increased without increasing the total losses or even reducing the switching losses compared to the standard IGBT.

The output filtering stage can be reduced when the converter’s switching frequency increases, and the output filtering stage can be reduced. That is, it needs less attenuation for the same output ripple. This implies that the cutoff frequency of the filter increases, and therefore also the resonance frequency of this filter. These effects increase the bandwidth of the control and, thus, the bandwidth of the whole converter.

A higher bandwidth of the converter translates into a better capacity to control fast-changing and high-frequency signals, which provides the following direct benefits for the user:

• A higher slew rate of output currents and voltages is especially noticeable when the equipment is used in power amplifier mode.
• But this is also very useful in any other mode to maintain the given set point while supporting fast transients and disturbances from the equipment connected to the output.
• Capacity to generate fundamental frequencies from 10 Hz to 1000 Hz.

• The voltage-frequency limit of the equipment is increased from 46000 V·Hz to 230000 V·Hz, which allows fundamentals of higher amplitude and frequency (230V @ 1000 Hz) and more harmonic content.
• Better control of harmonics up to 5000 Hz.

Standard Equipment of the same power that uses IGBTs has a switching frequency of 15 kHz, which falls in the higher range of the human audible range (20 Hz - 20 kHz), but it is still audible. This frequency normally represents a compromise between the audible noise and the switching losses of traditional IGBTs. Thanks to the SiC MOSFETs in our equipment, the switching noise is increased up to 60 kHz, making the switching completelyinaudible.

Despite the reduction of the output filter, the increase of the switching frequency is high enough to significantly improve the current ripple (3 times) and voltage ripple (2.75 times) due to the switching. This is thanks to an equilibrated selection of hardware elements and control adjustment.

The SiC MOSFETs are much more efficient than the IGBTs, not only regarding the switching losses but also regarding the conduction losses. Additionally, because the power filter is reduced, the losses of this filter are also reduced. Lastly, the MOSFET also incorporates a more efficient antiparallel SiC diode that also reduces the losses. All the effects translate into an increase in efficiency, despite that the switching frequency has been increased four times.

Thanks to the use of SiC MOSFETs at both converters of the backto-back configuration, the peak efficiency of the whole system is boosted above 94%.

The SiC MOSFETs used in the converter also include a SiC diode in antiparallel, which has better electrical characteristics than a standard silicon diode, specifically switching and conduction losses. On one side, this helps reduce global losses, but on the other, it allows higher re-circulation currents, which is a limiting factor when working in DC at nominal current and low voltages. Thanks to this SiC diode, our equipment now has the same current capacity in DC as in AC mode.

Choose your options:

• Three channel mode: allows different operation mode start/stop/reset per channel
• Isolation monitor (advised for IT systems)
• Anti-islanding monitor (only advised in net injection to the grid and following local regulations)
• RS485
• Battery Emulation

• Battery Test
• PV Panel Emulation
• Predefined Tests: LVRT, IEC 61000-4-11, 4-13, 4-14, 4-28 (consult us for specific Test)
• External gateway for RS232, CAN and others (consult us for specific gateway)

The user interface used by CINERGIA devices has been developed by our R&D team, to offer total control of the device, with a comfortable and intuitive design. This allows us to take full advantage of the capabilities of the device, as well as the programming and execution of standardized or self-created tests.