Broadly speaking, energy storage is the gathering of energy produced at one time, to be stored and used at a later time. For energy storage systems (ESS) there are two major use cases: creating utility-independent, solar-powered homes (residential ESS) and - on a larger scale - utilities supplementing generated power during periods of high demand (utility scale ESS).
Older generation residential solar energy systems are tied to the utility power grid via inverters which convert power from solar panels to AC electrical power during daylight hours. Marketable excess power might be sold back to utility companies. However, during the hours of darkness the end user is relying on the utility's electricity supply. Utility companies are aware of these limitations and adjust their pricing models accordingly. Residential customers pay based on so called "time-of-use" rates which are higher when solar power is not available.
This is where behind-the-meter ESS comes into play. The electricity that is collected via solar panels charges batteries - the energy is stored. When using these batteries with an inverter, the demand for AC power can be fulfilled at any time.
For residential ESS, the two main system-coupling topologies, which usually come along with PV installations, are the DC-coupled and the AC-coupled.
In a DC-coupled system, the energy stored in the battery is boosted to a certain DC-bus voltage, usually in the range of 400 V. This system is directly connected to the DC line using a DC-DC converter - not converting DC to AC.
In the AC-coupled system, the stored energy from the battery is supplied directly into the AC grid. In this case, both a DC-DC converter and an AC-DC inverter are used.
Both systems must be capable of bidirectional operation - drawing energy from the battery and charging the battery with excessively produced power.
Witness the top performance of CoolSiC™ trench MOSFETs 650 V with Infineon's latest simulation models.
3300 W, 54 V bidirectional phase-shift, full-bridge (PSFB) solution featuring 600 V CoolMOS™ CFD7 and XMC™ microcontroller
This evaluation board represents a complete system solution for a 3300 W bidirectional DC-DC converter that achieves 98% efficiency in buck mode and 97% in boost mode. The EVAL_3K3W_BIDI_PSFB is a DC-DC stage with telecom-level output realized by a phase-shift, full-bridge
(PSFB) topology block with bidirectional capability. The board features CoolMOS™ CFD7 and OptiMOS™ 5 in a full SMD solution with an innovative cooling concept.
Target applications: telecom, battery formation power, industrial robotics
3300 W CCM bidirectional totem-pole PFC unit using CoolSiC™ 650 V, 600 V CoolMOS™ C7, and digital control via XMC™ microcontroller
Infineon board components:
This evaluation board is a system solution for a bridgeless totem-pole power factor corrector (PFC) with bidirectional power capability.
The EVAL_3K3W_TP_PFC_SIC is enabled by Infineon's CoolSiC™ trench MOSFET and CoolMOS™ Superjunction power MOSFETs as well as isolated drivers and an XMC™ microcontroller.
Target applications are those requiring high efficiency (~99%) and high power density (72 W/in3), such as high-end server and telecom. In addition, the bidirectional power flow capability allows to address battery chargers or battery formation applications, too.
The integrated totem-pole operates in continuous-conduction mode (CCM) in both, rectifier (PFC) and inverter mode which also implements digital control on Infineon's XMC™ 1000 series microcontroller.
Target applications: high-end server, datacenter, telecom