Advanced smooth transition switch
View Patent ↗A bi-directional smooth transition switch with bumpless transfer is disclosed. It is composed of two feedback loops, each with feedback and forward-loop compensators. During loop operation, one feedback loop is active, while the other is inactive. The smooth transition switch operates in the following manner. The switch output is measured. Next, an error signal is formed as the difference between the forward-loop compensator output and the switch output, which is fed to the input of a high gain feedback compensator. The output of the feedback compensator is a feedback signal. When no switching occurs, the feedback signal remains zero in the active loop, and the output signal of the inactive loop will track the output signal of the active loop. When the switchover occurs, the inactive loop will replace the original active loop and provide smooth transition switch's output.
1. A smooth transition switch, comprising:
a switch having at least one control input, a first signal input, a second signal input and at least one output; and
at least one loop operably connected to said first signal input and said output, wherein said loop comprises:
a first summing junction having a plurality of inputs and at least one output operably connected to said first signal input of said switch;
a forward-loop compensator operably connected between said at least one output of said summing junction and said first signal input of said switch, wherein said forward-loop compensator is a simple proportional-integrate compensator;
another summing junction having a first input operably connected to an output of said forward-loop compensator and a second input operably connected to said output of said switch;
a feedback compensator operably connected between an output of said another summing junction and one of said inputs of said first summing junction; and
a second loop operably connected to said second signal input and said output of said switch, wherein said forward-loop compensator is a signal processor, whereby said forward-loop compensator processes an error signal using an equation with transfer function C(s)=(b 1 *s+b 0 )/(a 1 *s+1), where at, b 0 and b 1 are constant coefficients and s is said control input; and
said feedback compensator is a high gain compensator.
2. The smooth transition switch according to claim 1 , wherein said second loop comprises:
a second summing junction having a plurality of inputs and at least one output;
a second forward-loop compensator operably connected between said at least one output of said second summing junction and said second signal input of said switch;
a fourth summing junction having a first input operably connected to an output of said second forward-loop compensator and an input operably connected to said output of said switch; and
a second feedback compensator operably connected between an output of said fourth summing junction and an input of said second summing junction.
3. The smooth transition switch according to claim 1 , wherein at least one of said loops is a feedback loop, whereby a difference between an input signal and an output signal of said switch is fed to said input of said summing junction by said feedback compensator.
4. A smooth transition switch, comprising:
a switch having at least one control input, a first signal input, a second signal input and at least one output; and
at least one loop operably connected to said first signal input and said output wherein said loop comprises:
a first summing junction having a plurality of inputs and at least one output operably connected to said first signal input of said switch;
a forward-loop compensator operably connected between said at least one output of said summing junction and said first signal input of said switch, wherein said forward-loop compensator is a simple proportional-integrate compensator;
another summing junction having a first input operably connected to an output of said forward-loop compensator and a second input operably connected to said output of said switch; and
a feedback compensator operably connected between an output of said another summing junction and one of said inputs of said first summing junction, wherein said forward-loop compensator is a discrete signal processor, whereby said compensator processes an error signal using an equation with transfer function C(s)=(b 1 *s+b 0 )/(a 1 *s+1), where at, b 0 and b 1 are constant coefficients and s is said control input; and
said feedback compensator is a high gain compensator.
5. The smooth transition switch according to claim 4 , further comprising a second loop operably connected to said second signal input and said output of said switch, wherein said loop comprises:
a second summing junction having a plurality of inputs and at least one output;
a second feed forward compensator operably connected between said at least one output of said second summer and said second signal of said switch;
a fourth summing junction having a first input operably connected to an output of said second forward-loop compensator and an input operably connected to said output of said switch; and
a second feedback compensator operably connected between an output of said fourth summing junction and an input of said second summing junction.
6. The smooth transition switch according to claim 4 , wherein said at least one loop is a feedback loop, whereby a difference between an input signal and an output signal of said switch is fed to said input of said first summing junction by said feedback compensator.
7. A method of smooth transition switching, comprising the steps of:
reading a switch control signal;
reading a plurality of switch input signals;
reading at least one feedback signal;
generating at least one error signal;
forward-loop compensating said at least one error signal using a forward-loop compensator;
generating at least one switch input command signal;
switching an output command signal to said at least one input command signal;
calculating another error signal between an output command signal and an input command signal;
feedback compensating said error signal using a feedback compensator; and
generating at least one feedback signal, wherein said step of forward-loop compensating said error signal comprises processing said error signal using an equation with transfer function C(s)=(b 1 *s+b 0 )/(a 1 *s+1), where a 1 b 0 and b 1 are constant coefficients and s is said control input.
8. The method of smooth transition switching according to claim 7 , wherein said step of calculating said at least one error signal comprises the step of taking a difference between one of said input signals and said at least one feedback signal.
9. The method of smooth transition switching according to claim 7 , wherein said step of calculating another error signal comprises taking a difference between said at least one input command signal and said output command signal.
10. The method of smooth transition switching according to claim 7 , wherein said step of feedback compensating said error signal comprises applying a high gain compensator to said error signal.
11. The method of smooth transition switching according to claim 7 , wherein said step of calculating said at least one error signal comprises the step of taking a difference between one of said input signals and said at least one feedback signal; and
wherein said step of calculating another error signal comprises taking a difference between said at least one input command signal and said output command signal.
12. The method of smooth transition switching according to claim 7 , wherein said step of calculating said at least one error signal comprises the step of taking a difference between one of said input signals and said at least one feedback signal;
wherein said step of calculating another error signal comprises taking a difference between said at least one command signal and said output command signal; and
wherein said step of feedback compensating said error signal comprises applying a high gain compensator to said error signal.