2nd-Order Balancing and 2nd-Order Model Reduction

Model reduction of 2nd-order form systems is considered where a 2nd-order form reduced model is required. The focus is on reduction methods that employ or mimic Moore´s balance and truncate. First, we examine 2nd-order form model reduction by conversion to 1st-order form. Then, a direct 2nd-order balancing method is presented and, based on this, a 2nd-order form balance and truncate model reduction method is given. We illustrate results ad compare methods on three examples.