FIELD OF THE INVENTION

The present invention relates generally to the field of voltage surge protection in both DC and AC power systems, and more specifically to a circuit arrangement for a surge protection device for protecting multiple DC or AC power lines.

BACKGROUND OF THE INVENTION

With the proliferation of low voltage direct current (DC) in applications such as solar, data centers, electric vehicle charging stations, heating and air conditioning system, as well as many residential power systems, there is an increasing need for surge protection to appropriately protect such devices from power surges. A power surge (also referred to as a “voltage surge” or “transient voltage”) is an electrical transient, a short duration, high-energy impulse that is imparted on the normal electrical power system whenever there is a sudden electrical charge coupled into the electrical circuit. A power surge can originate from a variety of sources, both internal and external to an installed location, whether it is a residence, commercial building, solar array, or industrial facility.

A device that offers surge protection is a surge protection device or more commonly referred to as an SPD. An SPD is typically designed for either AC or DC applications.

The component that absorbs and passes a voltage surge inside an SPD is often referred to as a surge element. Surge elements include, but are not limited to, a metal oxide varistor (MOV), a transient voltage suppressor (TVS) diode, a thyristor surge protection device (TSPD), a gas discharge tube (GDT) and a spark gap overvoltage suppressor. Each SPD may include a plurality of surge elements connected in series, parallel, or a combination of series/parallel to achieve a particular surge rating for the SPD.

FIG. 1is a circuit diagram illustrating an exemplary prior art SPD10designed to protect a DC power system having multiple DC power lines. In this illustrative embodiment of a prior art SPD the surge elements14takes the form of MOVs (metal-oxide varistors). However, it should be appreciated that the surge elements of prior art SPDs may take other forms. The negative potential (N) is common between the five DC power lines (L1-L5). The five DC power lines are isolated from earth ground (G). Each of the five surge elements14have a respective status output16for indicating whether the respective surge element has failed. SPD10also includes an alarm circuit25for outputting an external alarm signal indicative of the status of SPD10. The status outputs16of the five surge elements14are summed by alarm circuit25. If the summation of status outputs16indicates that one or more of surge elements14has failed (i.e., a surge condition has occurred), then alarm circuit25provides an alarm signal by switching the alarm output. In the illustrated example, alarm circuit25has a normally open (NO) terminal, a normally closed (NC) terminal, and a common (COM) terminal for connection with an external circuit.

One of the drawbacks of existing prior art SPDs is that separate surge elements are respectively required between each DC power line (L1-L5) and the negative potential (N), and a separate surge element is required between the negative potential (N) and ground potential (G). Thus, SPD10requires a total of six surge elements14in order to protect a DC power system having 5 DC power lines. The need for this large number of surge elements makes the SPD costly to manufacture and requires a significant amount of space inside a housing for the SPD.

The above-described drawbacks in SPDs designed for DC applications are also present with respect to existing SPDs designed for AC applications for use in protection of multi-line, multiphase AC power systems.

The present invention overcomes these and other drawbacks of prior art SPDs to provide an SPD with a reduced number of surge elements for protection of multi-line DC and AC power systems.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a surge protection device, comprising: a plurality of power line inputs; a negative potential or neutral input; a ground potential input; a surge protection component having one or more surge elements; a rectification circuit including a plurality of diodes, wherein said rectification circuit is connected between said inputs and the surge protection component.

In accordance with another aspect of the present invention, there is provided a surge protection device, comprising: a plurality of AC multi-phase line inputs; a neutral input; a ground potential input; a plurality of surge protection components, each surge protection component having one or more surge elements; and a rectification circuit including a plurality of diodes, wherein said rectification circuit is connected between said line inputs and the surge protection component.

An advantage of the present invention is the provision of a SPD that requires fewer surge elements to protect multiple DC or AC power lines.

Another advantage of the present invention is the provision of a SPD that can be manufactured at a lower cost.

Still another advantage of the present invention is the provision of a SPD that minimizes space requirements for an SPD housing.

Yet another advantage of the present invention is the provision of a SPD that can be implemented with less circuitry to indicate a status condition of the SPD.

These and other advantages will become apparent from the following description of illustrated embodiments taken together with the accompanying drawings and the appended claims.

