Why Regenerative Energy Requires a New Approach to Voltage Stability and Load Management

Regenerative power is the process whereby the kinetic energy of a vehicle or machine is converted back into electrical energy. This energy would otherwise be lost, can be captured, and reused to increase efficiency and reduce energy consumption. This occurs in various systems, such as cranes, elevators, and industrial machinery. This technology was first developed in the 1890s. it became widely adopted in cranes, elevators, and industrial machinery in the 2000s.

Since regenerative power can represent 20% of electrical energy consumed, the environmental benefits related to the conservation of energy are immense. This reduction in utility supplied energy also represents an economic benefit to the user.

How Regenerative Power Occurs

Regenerative power is created when a device such as a crane or elevator descends, decelerates, or brakes. Kinetic energy from the device is then converted into electrical energy, which can be captured and stored for later use, or injected back into the electrical supply.

UPS and Regenerative Power: Why They Don't Work Together

Conventional Uninterruptible Power Supplies (UPS) are devices used to protect electrical equipment, such as computers and servers, from power outages and surges. They provide backup power in case of a power failure, preventing data loss and damage to electronic devices.

A UPS system consists of a battery, an inverter, and a charger. The battery charges when the power is on, and when the power goes out, the UPS system converts the stored DC power into AC power, which is what most electrical equipment uses. The UPS then provides this power to the connected devices, ensuring they continue to function despite the power outage.

When a UPS load is producing regenerative power, this reverse power cannot flow back through a conventional UPS. With regenerative power blocked at the DC Bus (the connection between the battery and rectifier), it causes voltage to rise. This will cause UPS shutdowns and may cause damage. Both will result in the load being dropped.

Power Quality Solutions when Regenerative Load is Present

When addressing voltage sags or outages in the presence of regenerative power, it's important to choose a solution that safely handles this reverse power without causing damage, while supporting the load. Possible solutions include: