As the United States enters the summer, I have begun to year out for a beach vacation, a day at the poolside barbecue. I grew up in southern Florida and now live in Texas. The hot and sunny days are familiar to me. Similarly, paying higher electricity bills in the summer has long been accustomed to me. From a positive perspective, the sunny days have brought many benefits, one of which is solar energy.
Solar energy helps reduce the costs associated with power generation. One of the hottest topics in the industry is power conversion efficiency. In order to increase the efficiency by 0.1%, solar inverter manufacturers often need to invest a lot of time. Considering the correlation between higher efficiency and increased energy, that is, the faster return on investment of photovoltaic (PV) systems, then the ability of the inverter to convert the solar panel's DC power to household AC power will be determined. It is important.
Micro-inverters and solar optimizers are two rapidly evolving architectures in the solar market. Figure 1 shows a typical block diagram of a solar microinverter. The micro-inverter converts power from a single PV module and is typically designed for a maximum output power of 250W to 400W.
To maximize PV panel performance, the front end of the micro-inverter is DC/DC stage, where the digital controller performs maximum power point tracking (MPPT). The most common topology is a non-isolated DC/DC boost converter. For a single solar panel, the rail or DC link is typically 36V; for this voltage range, you can use standard silicon metal-oxide-semiconductor field-effect transistors (MOSFETs) for DC/DC conversion.
In view of the fact that size reduction is a priority (so micro-inverters and power optimizers will be suitable for the back end of photovoltaic systems), solar inverter manufacturers are Gallium nitride (GaN) technology is used because it can switch at higher frequencies. Higher frequencies reduce the size of large magnetic components in micro-inverter and solar optimizer applications.
The DC/AC stage or secondary typically uses an H-bridge topology; for a micro-inverter, the track voltage is approximately 400V. Currently, gate drivers can use a variety of isolation techniques to isolate the controller from the power switch and simultaneously drive the high frequency switch. These requirements are driven by safety standards for signal isolation.
The UCC21220 Basic Isolated Gate Driver from Texas Instruments improves these by providing leading-edge performance for propagation delay and delay matching between the high and low sides. Integration advantages. These timing characteristics reduce the losses associated with the switch because it is faster to turn on, while also minimizing the on-time of the body diode, thereby increasing efficiency. These parameters are also less dependent on VDD, so you can relax the voltage tolerance design margin for the rest of the system, as shown in the workbench data in Figure 2. Figure 2 also shows that the UCC21220 provides faster propagation delays than competing products.
UCC21220 offers alternatives to solar applications, such as micro-inverters and solar optimizers, where basic isolation may be sufficient. The UCC21220 uses second-generation capacitive isolation technology to reduce cost through chip shrinkage, not only by providing typical propagation delays of 28ns, but also by reducing printed circuit board (PCB) space and system cost.
TI's GaN technology enables DC/DC boost and DC/AC inverter stages to operate at frequencies exceeding 100kHz. The inherent low switching losses of the GaN power stage allow it to achieve efficiencies of 99% or higher.
Higher efficiency means not only less energy wastage, but also smaller radiators, less cooling requirements, and more compact and cost-effective Benefit design. Using the right high-voltage gate drivers can help you achieve greater efficiency while reducing system cost in space-constrained micro-inverters or solar optimizer designs.