1. An electronic model predictive control apparatus for controlling a plant having a plant input signal and a plant output signal dependent on said plant input signal, comprising: a first memory containing a vector of data elements derived from a pseudo-inverse of an impulse response matrix model of said plant; a second memory containing data indicative of future plant input signal changes calculated during prior control cycles; a third memory containing a vector of past plant input signal changes; a fourth memory containing data elements by way of which a future plant output signal change due to past plant input signal changes may be derived from said vector of past plant input signal changes; an electronic processor adapted to: receive a plant output signal sample; calculate an expected future plant output signal from said data indicative of future plant input signal changes calculated during prior control cycles, said plant's steady-state gain, said future plant output signal change due to past plant input signal changes, and said plant output signal sample; calculate an error signal from a setpoint signal and said expected future plant output signal; and calculate a plant input signal change from said error signal, said vector of data elements derived from said pseudo-inverse, and said data indicative of future plant input signal changes calculated during prior control cycles; where said plant input signal change is applied to said plant input signal for controlling said plant output signal.