Power Conversion Systems Explained

Withdrawing from the power grid isn’t as simple as purchasing a bank of large-format batteries. You need smart hardware that can convert charging potential into synchronized power your facility can use. Whether you realize it or not, there will be PCS hardware components installed on-site for every energy storage project. 

Power Conversion System technology is the first line of interaction between your massive bank of stationary batteries and the electrical grid you’re connected to. Electricity flows from one side to the other in the span of milliseconds. Let’s take a deeper dive on how it all works.

What Is A Power Conversion System?

PCS stands for Power Conversion Systems. This unit is essentially the system’s brain, responsible for every conversion stage that occurs between your battery bank, which is DC, and the grid, which is AC. It’s a highly specialized, thermally engineered electrical cabinet that manages and controls how energy can flow through your system.

If your batteries are connected to the grid through a PCS, you can pull power from the utility to charge your batteries. You can also send that energy back out through the PCS and into your facility’s electrical circuits or the utility grid.

Power Conversion directly correlates to your levelized cost of storage. The better-performing your PCS units are, the less electricity you lose to heat during these conversion stages. With precise control of output voltage and frequency, your facility can technically island itself from the grid (during an emergency) or provide grid-support services like frequency regulation.

Bidirectional Inverter Technology Is Key 

Bidirectional inverter technology is the name of the game. In legacy power electronics, there was a rectifier stage used to charge a battery from AC->DC. Separately, an inverter stage was used to discharge batteries into your facility AC circuits.

These stages now occur within the same high-efficiency PCS stage. Because the inverter portion of this technology can work backwards to pull DC from your batteries, your battery bank can operate as both a load and a generator.

• When charging batteries from the grid: your bidirectional inverter technology will rectify whatever voltage is required from the grid (typically 480V/600V AC) down to the voltage required by your battery management system. 

• When peak shaving: the rectifier stage shuts off and the inverter section of your PCS essentially inverts DC from your batteries. It pulls power from your battery bank and synthesizes an AC sine wave to seamlessly match the voltage and phase of your utility.

How AC/DC Energy Conversion Works

Alternating current to direct current energy conversion occurs through intricate switching cycles. Internal insulated-gate bipolar transistors (IGBT) or silicon carbide (SiC) MOSFETs rapidly switch on and off thousands of times per second. This chops-up the inputted current which is then smoothed-out with inductors and capacitors.

AC/DC energy conversion is measured by efficiency. The less electricity that is lost as heat through the cooling system, the better. This is why many procurements mandate <3% losses during conversions stages. At a commercial scale, losing just 1% on AC/DC conversion can equal thousands of dollars of lost electricity during the lifetime of your power electronics.

A high-quality PCS will also have low-harmonic distortion on energy being imported back into your facility. You don’t want poor quality AC/DC conversion kicking back into your electric motors and harming sensitive digital controllers.

Grid-Tie Power Electronics Explained

Any system that plugs into the electrical grid needs specialized grid-tie power electronics to do so safely. These expensive components allow your system to go into grid-following or grid-forming mode.

Grid-following means the PCS is constantly monitoring the utility voltage and frequency then matching its output to sync with them. If your utility grid is getting weaker or stronger in frequency, your grid-tie power electronics will assist by raising/lowering the AC sine wave that your inverter exports.

Grid-tie power electronics are also responsible for keeping you and line workers safe. If your utility goes offline, your system detects it and immediately cuts off power from being exported to the external lines. This is called “anti-islanding” and is common among any grid-tie hardware you’ve worked with in the past. For facilities that need island mode: your PCS can bypass grid-following functions and become your own local frequency/voltage reference.

How To Add Grid Storage To Industrial Facilities

For commercial applications, implementation occurs in several major steps. Review these best practices before meeting with vendors to demo their product.

1. Analyze your site’s historical interval data. How many kW & kWh do you need? 

2. Verify that your breakers & protective relays are sized to handle the short-circuit current your PCS can produce.

3. Coordinate Modbus or CANbus communications between your PCS and existing EMS.

4. Once installed, commission your new PCS with a full load test to ensure conversion efficiencies match.

Partner with the Right Domestic Infrastructure Partner

There is plenty of scrutiny these days surrounding foreign born, owned, or influenced (FBOI) hardware. Companies like SolarBridge Technology have paved a path for domestic suppliers looking to gain ground in the wake of international tensions. By prioritizing equipment with little risk of future international regulations, procurement officers can focus on how a system will perform at their facility – not what country it comes from.

Americans know a quality product when they see it. Thirty years of microinverter heritage has given certain companies the reliability DNA to pass on to their high-performance power electronics. When designing for 20/25 year service lives, you want the best silicon and cabinet quality money can buy.

Call on SolarBridge Technology | Your American Energy Partner

SolarBridge Technology Inc. is a NON-FEOC domestic manufacturer, leading renewable energy with high-performance Power Conversion Systems for commercial and industrial applications. Located in Dallas Texas, our manufacturing facility has the capablities of developing PCS modules, and PCS cabinets.

Whether you need help modernizing old AC modules or have questions about installing a large scale Power Conversion System, our team is ready to help you join the energy independence movement. SolarBridge’s PCS technology was born from our award-winning inverter platform. With industry-leading bidirectional inverter technology, your battery storage will thank you for future-proofing against grid instability. Reach out today.