July
2005, Issue 180
Solar-Powered
Water Pump Controller
Cypress
PSoC High Integration Challenge 2004 Contest Winner
PRINCIPLE
PARTS
The
solar pump controller consists of three principle blocks:
the inverter waveform generator, the analog signal acquisition,
and the over-current detector. The elements that make
up these blocks consist of hardware and software components
in the CY8C27443 (see Figure 5).
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(Click
here to enlarge)
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Figure
5—The CY8C27443 hardware block diagram shows the
inverter waveform generator PWMs (bottom right).
The analog signal acquisition is at the top left.
The current-sensing circuits are at the bottom left. |
The
inverter waveform generator is responsible for directly
controlling the inverter power stage’s switching action.
It does this using three H-Bridge MOSFET switches (one
set for each phase). The switches are modulated at the
switching frequency by way of the CY8C27443’s pulse-width
modulator blocks. Additionally, the internal dead-band
generator times the break-before-make interval on the
H-Bridge. This delay is required to allow the switch
time to turn off before the complementary H-Bridge switch
is turned on. Three of the PWMDB8 blocks are used (one
for each phase). The top and bottom switches are connected
to phase 1 and phase 2, respectively.
