1. A message display system disposed in a vehicle comprising:
a display unit mounted in a manner such that a message displayed in said unit is viewable from outside of said vehicle;
a control mechanism integral with said vehicle for customizing the message displayed on the display unit;
said control mechanism having a message text box for displaying selected messages either input by said user or selected by scrolling arrows adjacent said message text box;
a remote control for uploading message selections and customizations made in said control mechanism by said user; and
said remote control having buttons for making a selection of a message to be displayed on the display unit from the message selections stored therein.
2. The message display system of claim 1 in which said control mechanism includes a group box in said display unit for displaying a group name, and group box scrolling arrows for scrolling through groups of messages in said group box.
3. The message display system of claim 1 in which said control mechanism includes customization buttons for selecting scroll characteristics, blinking characteristics, and text characteristics of the display unit.
4. The message display system of claim 3 in which said remote control has said selected messages arranged in columns with a button for each message for selection by the user for display on the display unit.
5. The message display system of claim 4 in which said remote control has auto-off and manual buttons, use of said auto-off button providing for termination of a displayed message after a predetermined period of time.
6. The message display system of claim 5 in which said remote control emits an audio alert when a message display time has expired.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A space vector modulation method for a multi-phase AC-AC direct conversion device that PWM-controls bidirectional switches with space vector modulation by a direct ACAC conversion system, the space vector modulation method for the AC-AC direct conversion device comprising:
defining a vector state in which a line voltage of multi-phase AC output is expanded onto a two-phase static \u03b1\u03b2 coordinates;
defining a phase-lagging simple harmonic oscillation vector axis and a phase-leading simple harmonic oscillation vector axis in a sector where an output voltage command value vector Vo* exists as an X axis and a Y axis respectively;
setting maximum voltage vectors XL, YL, middle vectors XM, YM and minimum vectors XS, YS in the each axis, a zero vector Z that is an intermediate voltage phase of a power source, and a rotation vector R that is one rotation vector existing in the sector, as base vectors;
determining a switching selection pattern formed by a combination of four vectors among the eight varieties of vectors, which satisfies predetermined conditions for reducing higher harmonics of an input current andor an output voltage,
deriving a duty coefficient matrix associated with the input and output for the four vectors of this selection pattern on the basis of power source voltage information and output current information;
calculating its inverse matrix and determining a duty solution of the four vectors; and
converting input and output waveforms into sine waves simultaneously by the determined duty solution.
2. The space vector modulation method for the AC-AC direct conversion device as claimed in claim 1, wherein:
the predetermined conditions have at least one or more conditions from the following conditions;
the input waveform and the output waveform can be simultaneously converted into the sine waves.
a vector whose voltage difference from a command value when viewed toward a line voltage vector direction is a maximum is not selected.
a switching transition every one phase is possible.
a direct commutation between a maximum voltage phase and a minimum voltage phase of the power source does not occur upon the switching transition.
the zero vector of the intermediate voltage phase of the power source is used all the time.
3. The space vector modulation method for the AC-AC direct conversion device as claimed in claim 1, wherein:
of all the space vectors of the AC-AC direct conversion device, an output side space vector is listed in tabular form as coefficients of a three-phase two-phase converted \u03b1 component Vi\u03b1 of a power source phase voltage detection value and a three-phase two-phase converted \u03b2 component Vi\u03b2 of the power source phase voltage detection value,
an input side space vector is listed in tabular form as coefficients of a three-phase two-phase converted \u03b1 component Io\u03b1 of an output load current detection value and a three-phase two-phase converted \u03b2 component Io\u03b2 of the output load current detection value, and
the duty solution of the four vectors is determined by using the table.
4. The space vector modulation method for the AC-AC direct conversion device as claimed in claim 1, wherein:
when determining the duty solution, a check is previously made whether the inverse matrix is present for the each selection pattern of the four vectors, and
a selection pattern, the duty solution of which can be obtained, is used as a final duty.
5. The space vector modulation method for the AC-AC direct conversion device as claimed in claim 1, wherein:
when determining the duty solution, the operation is performed with a row whose duty addition value becomes 1 eliminated in the duty coefficient matrix.
6. The space vector modulation method for the AC-AC direct conversion device as claimed in claim 1, wherein:
as the selection pattern, on the basis of magnitude of the output voltage command value,
in a case of a low output voltage area, a selection pattern containing the zero vector is used, and
in a case of a high output voltage area, a selection pattern containing no zero vector is used.
7. The space vector modulation method for the AC-AC direct conversion device as claimed in claim 1, wherein:
a determinant of the duty coefficient matrix whose inverse matrix is present is previously listed in tabular form for the selection patterns, and
the duty solution of the four vectors is determined by using the table.
8. The space vector modulation method for the AC-AC direct conversion device as claimed in claim 1, wherein:
the selection pattern is fixed according to lag or lead of a rotation vector phase in the sector of the output side space vector.
9. The space vector modulation method for the AC-AC direct conversion device as claimed in claim 1, wherein:
the selection pattern is fixed according to comparison of magnitude of a connection between the middle voltage vectors XM and YM of the simple harmonic oscillation vectors and the output voltage command value.
10. The space vector modulation method for the AC-AC direct conversion device as claimed in claim 1, wherein
as the selection pattern, a selection pattern having two levels is used in preference to the others.
11. The space vector modulation method for the AC-AC direct conversion device as claimed in claim 1, wherein
at a time when the current detection value is small or at an initial operating start-up, the operation for determining the duty solution of the four vectors is performed on the basis of the power source voltage information and an output current command value.