Inverter for use with solar arrays
First Claim
1. In a system for generating an N phase alternating electric current by using switching means controlled by a controller to intermittently connect a number M of solar arrays (listed in order of decreasing output voltage as D1, D2, . . . Di . . . DM) to the lines L1, L2, . . . Lk . . . LN where N is an odd number equal to or greater than M, the improvement comprising:
- control means for controlling the switching means to connect Di to Lk in a positive sense for an interval of duration 90°
/N beginning at ##EQU10## where δ
is any constant angle, and for controlling the switching means to connect Di to Lk in a negative sense for an interval of duration 90°
/N beginning at ##EQU11## for all values of i and k, where 1<
i≦
M and 1<
k≦
N, whereby at any particular instant no more than one array is feeding a particular line, and whereby each array is utilized 100% of the time.
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Abstract
A controlled switching system for converting the output of several photovoltaic solar arrays into a polyphase alternating electric current. Each array is utilized 100% of the time, and at any particular instant only one array or no array is feeding a particular phase. The specific line to which an array is connected is altered in a cyclic manner by the switching system to synthesize the polyphase current. Energy is not stored in the switching system, but instead is made available as polyphase electric current as soon as it is generated by the photovoltaic arrays. Each phase approximates a sine wave to an extent that is limited by the number of arrays. For the closest approximation, the arrays must be configured to have prescribed voltages and currents. Alternatively, a single array may be partitioned electrically in such a way that the desired voltages and currents are attained.
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Citations
16 Claims
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1. In a system for generating an N phase alternating electric current by using switching means controlled by a controller to intermittently connect a number M of solar arrays (listed in order of decreasing output voltage as D1, D2, . . . Di . . . DM) to the lines L1, L2, . . . Lk . . . LN where N is an odd number equal to or greater than M, the improvement comprising:
control means for controlling the switching means to connect Di to Lk in a positive sense for an interval of duration 90°
/N beginning at ##EQU10## where δ
is any constant angle, and for controlling the switching means to connect Di to Lk in a negative sense for an interval of duration 90°
/N beginning at ##EQU11## for all values of i and k, where 1<
i≦
M and 1<
k≦
N, whereby at any particular instant no more than one array is feeding a particular line, and whereby each array is utilized 100% of the time.- View Dependent Claims (2, 3, 4)
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5. In a system for generating a 2N-phase electric current by switching means controlled by a controller to intermittently connect M pairs of solar arrays, each pair consisting of two identical arrays and listed in order of decreasing output voltage as (D1, D1 '"'"') . . . (Di, Di '"'"') . . . (DM, DM '"'"') where 1≦
- i≦
M and where each array has a positive terminal and a negative terminal, to the lines Ll, . . . Lk, . . . LN and to the lines Ll '"'"', . . . Lk '"'"' . . . LN '"'"', where 1≦
k≦
N and where 1≦
M≦
N, the improvement comprising;grounding means connecting the negative terminals of D1, D2, . . . DM and the positive terminals of D1 '"'"', D2 '"'"' . . . DM '"'"' to ground; and
,control means for controlling the switching means to connect the positive terminal of Di to Lk and simultaneously to connect the negative terminal of Di '"'"' to Lk '"'"' for an interval of 90°
/N beginning at ##EQU12## and for controlling the switching means to connect the negative terminal of Di '"'"' to Lk and simultaneously to connect the positive terminal of Di to Lk '"'"' for an interval of 90°
/N beginning at ##EQU13## for all values of i and k, where 1≦
i≦
M and 1≦
k≦
N and where δ
is any constant angle, whereby at any particular instant no more than one array is feeding a particular line, and whereby each array is utilized 100% of the time. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
- i≦
Specification