Real-time multi-array sum power spectrum control
Power control for a radar system issues power draw commands to each array in the radar system. Each power draw command controls direct current (DC) power draw by the respective radar array on a dwell-by-dwell basis, based on total energy resources (including stored energy) available to the respective array at the start of a dwell period, a power spend rate expected for the respective array during the dwell period, and a rate of “waste” power set to be dispersed to reduce excess power at the respective array during the dwell period. In determining power draw for an array, the power control takes into account a predetermined number of future dwell periods and any transmit and/or receive tasks scheduled for such periods. If necessary to maintain less than a predetermined ripple on total DC power drawn from a source of the DC power by the radar system, the power control adjusts a duration of empty dwell periods within the dwell schedule for one or more of the arrays.
1. An apparatus, comprising:
a plurality of radar arrays; and
a power control system configured to issue power draw commands to each of the radar arrays, the power draw commands configured to control direct current (DC) power draw by the respective radar array on a dwell-by-dwell basis, taking into account a predetermined number of future dwell periods within a dwell schedule for the respective radar array;
the power control system further configured to adjust a duration of an empty dwell period between two consecutive transmit and/or receive tasks within the dwell schedule for the respective radar array in order to maintain less than a predetermined ripple on total DC power drawn from a source of the DC power by a radar system that includes the plurality of radar arrays;
the power control system further configured to constrain total DC power draw on a dwell-by-dwell basis for all of the radar arrays, collectively.
2. The apparatus according to claim 1 , wherein the power control system is configured to determine a rate of DC power draw on a dwell-by-dwell basis by each of the radar arrays.
3. The apparatus according to claim 1 , wherein the power control system is configured to constrain the total DC power draw on a dwell-by-dwell basis for all of the radar arrays, collectively, according to:
f
Y
0
+
∑
t
=
0
h
d
t
(
f
D
t
-
f
U
t
-
f
S
t
)
≥
E
min
,
f
∈
{
1
,
2
,
3
,
4
}
,
f
Y
0
+
∑
t
=
0
h
d
t
(
f
D
t
-
f
U
t
-
f
S
t
)
≤
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max
,
f
∈
{
1
,
2
,
3
,
4
}
,
∑
f
=
1
4
D
t
f
≤
P
max
,
∀
t
,
and
∑
f
=
1
4
D
t
f
≥
P
min
,
∀
t
,
where f Y 0 is an initial energy resource state for a respective face fat a start of a dwell period t, f D t is a rate of power draw to be drawn by the respective face f during the dwell period t, f S t is a rate of power spend for a transmit/receive operation, if any, by the respective face f during the dwell period t, f U t is a rate of unallocated power directed to a load other than one of the faces f during the dwell period t to reduce excess power at the respective face f, d t is a duration of the dwell period t, E min and E max are respectively minimum and maximum energies allowed to maintain less than the predetermined ripple, and P max and P min are respectively maximum and minimum powers allowed to maintain less than the predetermined ripple.
4. The apparatus according to claim 1 , wherein the power control system comprises a plurality of circuits for each of the plurality of radar arrays, each circuit including:
a DC/DC converter having a current error feedback loop and a voltage error feedback loop configured to receive a reference voltage and a current command portion of each of the power draw commands,
an energy storage connected to an output of the DC/DC converter,
one or more linear regulators connected to the output of the DC/DC converter, and
one or more radio frequency (RF) modules connected to one or more outputs of the one or more linear regulators and configured to receive a transmit/receive command portion of each of the power draw commands.
5. The apparatus according to claim 4 , wherein:
the plurality of circuits for each of the plurality of radar arrays are controlled together.
6. The apparatus according to claim 4 , wherein the energy storage comprises one or more capacitors.
7. The apparatus according to claim 4 , wherein:
the power control system comprises one or more loads that are configured to be selectively connected to one of the radar arrays to disperse excess power at the respective radar array.
8. The apparatus according to claim 1 , wherein the power control system is configured to sum power requirements for the radar arrays to determine the total DC power drawn from the source by the radar system.
9. The apparatus according to claim 1 , wherein the power control system is configured to extend the duration of the empty dwell period.
10. The apparatus according to claim 1 , wherein the power control system is configured to constrain the total DC power draw on a dwell-by-dwell basis for all of the radar arrays, collectively, based on an initial energy resource state for a respective face at a start of a dwell period, a rate of power draw to be drawn by the respective face during the dwell period, a rate of power spend for a transmit/receive operation, if any, by the respective face during the dwell period, a rate of unallocated power directed to a load other than one of the faces during the dwell period to reduce excess power at the respective face, a duration of the dwell period, minimum and maximum energies allowed to maintain less than the predetermined ripple, and maximum and minimum powers allowed to maintain less than the predetermined ripple.
11. A method, comprising:
coupling a plurality of radar arrays to a source of direct current (DC) power;
issuing power draw commands to each of the radar arrays, the power draw commands controlling DC power draw by the respective radar array on a dwell-by-dwell basis, taking into account a predetermined number of future dwell periods within a dwell schedule for the respective radar array;
adjusting a duration of an empty dwell period between two consecutive transmit and/or receive tasks within the dwell schedule for the respective radar array in order to maintain less than a predetermined ripple on total DC power drawn from the source by a radar system that includes the plurality of radar arrays; and
constraining total DC power draw on a dwell-by-dwell basis for all of the radar arrays, collectively.
12. The method according to claim 11 , further comprising:
determining a rate of DC power draw on a dwell-by-dwell basis by each of the radar arrays.
13. The method according to claim 11 , wherein the total DC power draw is constrained on a dwell-by-dwell basis for all of the radar arrays, collectively, according to:
f
Y
0
+
∑
t
=
0
h
d
t
(
f
D
t
-
f
U
t
-
f
S
t
)
≥
E
min
,
f
∈
{
1
,
2
,
3
,
4
}
,
f
Y
0
+
∑
t
=
0
h
d
t
(
f
D
t
-
f
U
t
-
f
S
t
)
≤
E
max
,
f
∈
{
1
,
2
,
3
,
4
}
,
∑
f
=
1
4
D
t
f
≤
P
max
,
∀
t
,
and
∑
f
=
1
4
D
t
f
≥
P
min
,
∀
t
,
where f Y 0 is an initial energy resource state for a respective face f at a start of a dwell period t, f D t is a rate of power draw to be drawn by the respective face f during the dwell period t, f S t is a rate of power spend for a transmit/receive operation, if any, by the respective face f during the dwell period t, f U t is a rate of unallocated power directed to a load other than one of the faces f during the dwell period t to reduce excess power at the respective face f, d t is a duration of the dwell period t, E min and E max are respectively minimum and maximum energies allowed to maintain less than the predetermined ripple, and P max and P min are respectively maximum and minimum powers allowed to maintain less than the predetermined ripple.
14. The method according to claim 11 , further comprising:
implementing a power control system comprising a plurality of circuits for each of the plurality of radar arrays, each circuit including:
a DC/DC converter having a current error feedback loop and a voltage error feedback loop configured to receive a reference voltage and a current command portion of each of the power draw commands,
an energy storage connected to an output of the DC/DC converter,
one or more linear regulators connected to the output of the DC/DC converter, and
one or more radio frequency (RF) modules connected to one or more outputs of the one or more linear regulators and configured to receive a transmit/receive command portion of each of the power draw commands.
15. The method according to claim 14 , wherein:
the plurality of circuits for each of the plurality of radar arrays are controlled together.
16. The method according to claim 14 , wherein the energy storage comprises one or more capacitors.
17. The method according to claim 14 , wherein:
the power control system comprises one or more loads that are configured to be selectively connected to one of the radar arrays to disperse excess power at the respective radar array.
18. The method according to claim 11 , further comprising:
summing power requirements for the radar arrays to determine the total DC power drawn from the DC power source by the radar system.
19. The method according to claim 11 , further comprising:
extending the duration of the empty dwell period.
20. The method according to claim 11 , wherein the total DC power draw is constrained on a dwell-by-dwell basis for all of the radar arrays, collectively, based on an initial energy resource state for a respective face at a start of a dwell period, a rate of power draw to be drawn by the respective face during the dwell period, a rate of power spend for a transmit/receive operation, if any, by the respective face during the dwell period, a rate of unallocated power directed to a load other than one of the faces during the dwell period to reduce excess power at the respective face, a duration of the dwell period, minimum and maximum energies allowed to maintain less than the predetermined ripple, and maximum and minimum powers allowed to maintain less than the predetermined ripple.