Power converter and power unit
First Claim
Patent Images
1. A power converter comprising a power conversion unit having an n-phase alternating current output (n is an integer number with n≧
- 2) connected to a direct current power source, and smoothing means provided between the direct current power source and the power conversion unit,wherein the power conversion unit comprises control means which allows the whole of a phase difference of a power waveform of each phase to be matched to a value dividing a cycle of the power waveform into n-equal portions, and at the same time, the whole of a power value of each phase is controlled to be identical.
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Abstract
Control means is provided, in which the whole of the phase difference of a power waveform of each phase is matched to a value dividing a cycle of the power waveform into n-equal portions, and at the same time, the whole of the power value of each phase is controlled to be identical, so that the power conversion unit having a n-alternating current output (n is an integer numeral serving as n≧2) connected to the direct current power source and smoothing means provided between the direct current power source and the power conversion unit are made small in capacity.
239 Citations
25 Claims
-
1. A power converter comprising a power conversion unit having an n-phase alternating current output (n is an integer number with n≧
- 2) connected to a direct current power source, and smoothing means provided between the direct current power source and the power conversion unit,
wherein the power conversion unit comprises control means which allows the whole of a phase difference of a power waveform of each phase to be matched to a value dividing a cycle of the power waveform into n-equal portions, and at the same time, the whole of a power value of each phase is controlled to be identical. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
- 2) connected to a direct current power source, and smoothing means provided between the direct current power source and the power conversion unit,
-
12. A power converter comprising a power conversion unit which is connected to a direct current power source and outputs a three phase alternating current, and smoothing means provided between the direct current power source and the power conversion unit, comprising:
- voltage detection means for detecting the voltage of a first phase, a second phase and a third phase of three phases; and
control means in which, based on the first phase among the three phases;
a second phase component of a second phase line current is increased and decreased to be adjusted in accordance with a phase voltage of the second phase, and the amount of a reverse code of the adjusted portion of the second phase component is increased and decreased to be adjusted by being distributed to the line current of the first phase and the line current of the third phase, and based on the first phase among the three phases, the third phase component of the line current of the third phase is increased and decreased to be adjusted in accordance with the phase current of the third phase, and the amount of the reverse code of the adjusted portion of the third phase component is increased and decreased to be adjusted by being distributed to the line current of the first phase and the line current of the second phase; and
at the same time, for the total value psum(t) of an instantaneous power of the three phases;
psum(t)=the phase voltage of the first phase×
the line current of the first phase+the phase voltage of the second phase×
the line current of the second phase+the phase voltage of the third phase×
the line current of the third phasethe following expression;
d(psum)/dt≈
0is satisfied. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
v2=V2×
sin(θ
+2π
/3)
v3=V3×
sin(θ
+4π
/3),and based on the first phase,
Ga=V2/V1
Gb=V3/V1the power converter controls the current i1 of the first phase, the current i2 of the second phase and the current i3 of the third phase so as to become the following expressions;
i1=I0×
(sin(θ
)+I12×
sin(θ
+2π
/3)+I13×
sin(θ
+4π
/3))
i2=I0×
((1−
2×
Ka)×
sin(θ
+2π
/3)+I23×
sin(θ
+4π
/3))
i3=I0×
(I32×
sin(θ
+2π
/3)+(1−
2×
Kb)×
sin(θ
+4π
/3))
I12+I32=2×
Ka
I13+I23=2×
Kb(I0 is an arbitrary number) provided that
Ka=(V2−
V1)/(2×
V2+V1)=(Ga−
1)/(2×
Ga+1)
Kb=(V3−
V1)/(2×
V3+V1)=(Gb−
1)/(2×
Gb+1).
- voltage detection means for detecting the voltage of a first phase, a second phase and a third phase of three phases; and
-
15. The power converter according to claim 13, wherein in case where a voltage v1 of the first phase, a voltage v2 of the second phase and a voltage v3 of the third phase are given by the following expressions:
-
v1=V1×
sin(θ
)
v2=V2×
sin(θ
+2π
/3)
v3=V3×
sin(θ
+4π
/3),and based on the first phase,
Ga=V2/V1
Gb=V3/V1the power converter controls the current i1 of the first phase, the current i2 of the second phase and the current i3 of the third phase so as to become the following expressions;
i1=I0×
(sin(θ
)+I12×
sin(θ
+2π
/3)+I13×
sin(θ
+4π
/3))
i2=I0×
((1−
2×
Ka)×
sin(θ
+2π
/3)+I23×
sin(θ
+4π
/3))
i3=I0×
(I32×
sin(θ
+2π
/3)+(1−
2×
Kb)×
sin(θ
+4π
/3))
I12+I32=2×
Ka
I13+I23=2×
Kb(I0 is an arbitrary number) provided that
Ka=(V2−
V1)/(3×
V2)=(Ga−
1)/(3×
Ga)
Kb=(V3−
V1)/(3×
V3)=(Gb−
1)/(3×
Gb).
-
-
16. The power converter according to claim 14 or 15, wherein, by way of
-
I12=I32=Ka
I13=I23=Kb,the current i of the first phase, the current i2 of the second phase and the current i3 of the third phase are controlled so as to become the following expressions;
i1=I0×
(sin(θ
)+Ka×
sin(θ
+2π
/3)+Kb×
sin(θ
+4π
/3))
i2=I0×
((1−
2×
Ka)×
sin(θ
+2π
/3)+Kb×
sin(θ
+4π
/3))
i3=I0×
(Ka×
sin(θ
+2π
/3)+(1−
2×
Kb)×
sin(θ
+4π
/3)).
-
I12=I32=Ka
-
17. The power converter according to claim 14 or 15, the current i1 of the first phase, the current i2 of the second phase and the current i3 of the third phase are controlled so as to become the following expressions:
-
I12=2×
Ka×
(V3/(V1+V3)), I32=2×
Ka×
(V1/(V1+V3)),
I13=2×
Kb×
(V2/(V1+V2)), I23=2×
Kb×
(V1/(V1+V2)).
-
-
18. The power converter according to claim 12, wherein each phase current is further current-controlled to an advancing or a lagging phase with the same phase.
-
19. The power converter according to claim 12, wherein a phase having the second largest magnitude of the phase voltage among the three phases is selected as a first reference phase.
-
20. The power converter according to claim 12, comprising:
a first storage portion in which the smoothing means is connected in parallel with the direct current power source between the direct current power source and the power conversion unit;
a bi-directional power conversion unit having one terminal connected in parallel with the first storage portion;
a second storage portion connected to the other terminal of the bi-directional power conversion unit; and
smoothing control means for controlling a power flow of the bi-directional power conversion unit such that a ripple of the first storage portion becomes small.
-
21. The power converter according to claim 20, wherein the smoothing control means detects the ripple of the first storage portion and controls the power flow of the bi-directional power conversion unit such that the detected ripple becomes small.
-
22. The power converter according to claim 20, wherein the smoothing control means detects the lower harmonic of the output voltage of the power conversion unit and/or the lower harmonic of the output current, and controls the bi-directional power conversion unit such that the ripple of the first storage portion becomes small in accordance with the lower harmonic.
-
23. The power converter according to claim 12, wherein the direct current power source is either the solar cell or the fuel cell.
-
24. The power converter according to claim 12, wherein the power source comprises a solar cell or a fuel cell and a DC/DC converter for voltage-converting and outputting a direct output from the solar cell or the fuel cell.
-
25. A power unit comprising the direct current power source and the power converter according to claim 12 connected to the direct current power source.
Specification
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Current AssigneeCanon Kabushiki Kaisha (Canon Inc.)
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Original AssigneeCanon Kabushiki Kaisha (Canon Inc.)
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InventorsNakanishi, Manabu, Takehara, Nobuyoshi, Kurokami, Seiji
-
Primary Examiner(s)RILEY, SHAWN
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Application NumberUS10/792,713Publication NumberTime in Patent Office613 DaysField of Search136/205, 136/206, 307/154, 363/41US Class Current307/154CPC Class CodesH02M 7/53871 with automatic control of o...
