Dual active bridge control to minimize DC link resonance
Systems and methods for operating dual active bridge (DAB) converters are provided herein. The systems and methods include sending a first control signal to toggle a first pair of switches of a bridge of the DAB converter and sending a second control signal to toggle a second pair of switches of the bridge, where a temporal delay, based on a resonance time for the bridge, separates the toggling caused by the first control signal from the toggling caused by the second control signal.
1 . A method comprising:
sending a first control signal to toggle a first pair of switches of a bridge of a dual active bridge (DAB) converter; and
sending a second control signal to toggle a second pair of switches of the bridge, wherein:
a temporal delay separates the toggling caused by the first control signal from the toggling caused by the second control signal; and
the temporal delay is based on a resonance time for the bridge to cause destructive resonance of a first ripple current generated by toggling the first pair of switches and a second ripple current generated by toggling the second pair of switches.
2 . The method of claim 1 , wherein:
the resonance time for the bridge is based on a capacitance of at least two capacitors coupled to the bridge and an inductance between the at least two capacitors coupled to the bridge; and
the temporal delay corresponds to half of the resonance time.
3 . The method of claim 1 , further comprising:
sending third and fourth control signals to respectively toggle the first and second pairs of switches of the bridge, wherein:
the temporal delay separates the toggling caused by the third control signal from the toggling caused by the fourth control signal;
a duty cycle interval separates the toggling caused by the first and third control signals;
the duty cycle interval separates the toggling caused by the second and fourth control signals; and
the duty cycle interval is based on a maximum duty ratio for the first and second pairs of switches of the bridge and a sampling time of the DAB converter.
4 . The method of claim 3 , wherein the maximum duty ratio is 0.5*(T s −T res )/T s , wherein T s is the sampling time of the DAB converter and T res is the resonance time for the bridge of the DAB converter.
5 . The method of claim 3 , wherein the maximum duty ratio is 0.5*(T s −n*T res )/T s , wherein T s is the sampling time of the DAB converter, T res is the resonance time for the bridge of the DAB converter, and n is an odd scalar of the resonance time.
6 . The method of claim 1 , wherein the bridge is a primary bridge of the DAB converter and the temporal delay is a first temporal delay, the method further comprising:
sending a fifth control signal to toggle a third pair of switches of a secondary bridge of the DAB converter; and
sending a sixth control signal to toggle a fourth pair of switches of the secondary bridge, wherein:
a second temporal delay separates the toggling caused by the fifth control signal from the toggling caused by the sixth control signal; and
the second temporal delay is based on a resonance time for the secondary bridge.
7 . The method of claim 6 , further comprising:
sending seventh and eighth control signals to respectively toggle the third and fourth pairs of switches of the secondary bridge, wherein:
the second temporal delay separates the toggling caused by the seventh control signal from the toggling caused by the eighth control signal;
a duty cycle interval separates the toggling caused by the fifth and seventh control signals;
the duty cycle interval separates the toggling caused by the sixth and eighth control signals; and
the duty cycle interval is based on a maximum duty ratio for the third and fourth pairs of switches of the bridge and a sampling time of the DAB converter.
8 . The method of claim 6 , wherein:
the toggling caused by the first control signal and the toggling caused by the fifth control signal are separated by a phase shift delay.
9 . The method of claim 8 , wherein:
when a determined duty cycle of a primary side or secondary side of the DAB converter is limited by a maximum duty ratio, the phase shift delay is adjusted based on the maximum duty ratio to modify an output power of the DAB converter.
10 . The method of claim 1 , wherein the first ripple current and the second ripple current cancel at a capacitor of the bridge.
11 . A method comprising:
sending a first control signal to toggle a first pair of switches of a primary bridge of a dual active bridge (DAB) converter;
sending a second control signal to toggle a second pair of switches of the primary bridge; and
sending a fifth control signal to toggle a third pair of switches of a secondary bridge of the DAB converter, wherein:
a phase shift delay separates the toggling caused by the first control signal from the toggling caused by the fifth control signal;
when a determined duty cycle of a primary side or secondary side of the DAB converter is limited by a maximum duty ratio, the phase shift delay is adjusted based on the maximum duty ratio to modify an output power of the DAB converter;
a temporal delay separates the toggling caused by the first control signal from the toggling caused by the second control signal; and
the temporal delay is based on a resonance time of the primary bridge to cause destructive resonance of a first ripple current generated by toggling the first pair of switches and a second ripple current generated by toggling the second pair of switches.
12 . A system, comprising:
first and second pairs of switches coupled to a bridge of a dual active bridge (DAB) converter; and
control circuitry coupled to the first and second pairs of switches and configured to:
send a first control signal to toggle the first pair of switches; and
send a second control signal to toggle the second pair of switches, wherein:
a temporal delay separates the toggling caused by the first control signal from the toggling caused by the second control signal; and
the temporal delay is based on a resonance time for the bridge to cause destructive resonance of a first ripple current generated by toggling the first pair of switches and a second ripple current generated by toggling the second pair of switches.
13 . The system of claim 12 , further comprising at least two capacitors coupled to the bridge, wherein:
the resonance time for the bridge is based on a capacitance of the at least two capacitors and an inductance between the at least two capacitors; and
the temporal delay corresponds to half of the resonance time.
14 . The system of claim 12 , wherein the control circuitry is further configured to:
send third and fourth control signals to respectively toggle the first and second pairs of switches of the bridge, wherein:
the temporal delay separates the toggling caused by the third control signal from the toggling caused by the fourth control signal;
a duty cycle interval separates the toggling caused by the first and third control signals;
the duty cycle interval separates the toggling caused by the second and fourth control signals; and
the duty cycle interval is based on a maximum duty ratio for the first and second pairs of switches of the bridge and a sampling time of the DAB converter.
15 . The system of claim 14 , wherein the maximum duty ratio is: 0.5*(T s −T res )/T s , wherein T s is the sampling time of the DAB converter and T res is the resonance time for the bridge of the DAB converter.
16 . The system of claim 14 , wherein the maximum duty ratio is: 0.5*(T s −n*T res )/T s , wherein T s is the sampling time of the DAB converter, T res is the resonance time for the bridge of the DAB converter, and n is an odd scalar of the resonance time.
17 . The system of claim 12 , wherein the bridge is a primary bridge of the DAB converter, the system further comprises third and fourth pairs of switches coupled to a secondary bridge of the DAB converter, and the temporal delay is a first temporal delay, and wherein the control circuitry is further configured to:
send a fifth control signal to toggle a third pair of switches of the secondary bridge of the DAB converter; and
send a sixth control signal to toggle a fourth pair of switches of the secondary bridge, wherein:
a second temporal delay separates the toggling caused by the fifth control signal from the toggling caused by the sixth control signal; and
the second temporal delay is based on a resonance time for the secondary bridge.
18 . The system of claim 17 , wherein the control circuitry is further configured to:
send seventh and eighth control signals to respectively toggle the third and fourth pairs of switches of the secondary bridge, wherein:
the second temporal delay separates the toggling caused by the seventh control signal from the toggling caused by the eighth control signal;
a duty cycle interval separates the toggling caused by the fifth and seventh control signals;
the duty cycle interval separates the toggling caused by the sixth and eighth control signals; and
the duty cycle interval is based on a maximum duty ratio for the third and fourth pairs of switches of the bridge and a sampling time of the DAB converter.
19 . The system of claim 18 , wherein:
the toggling caused by the first control signal and the toggling caused by the fifth control signal are separated by a phase shift delay.
20 . The system of claim 19 , wherein:
when a determined duty cycle of a primary side or secondary side of the DAB converter is limited by a maximum duty ratio, the phase shift delay is adjusted based on the maximum duty ratio to modify an output power of the DAB converter.