Embed Size (px)
Citation preview
Controller Designof Power Quality-Improving
Appliances
PNNL-SA-55816
D. J. Hammerstrom, N. Zhou, and N. LuPacific Northwest National Laboratory
902 Battelle Blvd., P. O. Box 999Richland, WA 99352 USA
[email protected](509) 372-4087
time
curr
ent
Excessive PQIcurrent correctionPerfect PQIcurrent correctionInadequate PQIcurrent correctionNon-PQI currents
Let one load improve the power quality and power factor for an entire premise
Power Quality-Improving Appliances
33
Sum of currents
Voltage
PQI current
Voltage
Shifted current
Voltage
Premise current before PQI
PQI current
Sum of premise and PQI currents
PQI appliances are like filters, but they can only consume energy. Where the energy can be put to good use, the PQI is, in theory, 100% efficient.
V
IPremise
IPremise
IPremise+PQI
Measure and Improve Current at Premise Service Panel
Controller Input Signals
GainRectified ac voltageRectified premise current
Note: PQI controller design can be greatly simplified by using an inexpensive power factor control chip.
A Simple, Nearly Failsafe Power Circuit
Line 1 Line 2 / N
IGBT 1 IGBT 2
Load
Most circuit failure modes would result in normal, rated appliance conduction.
Floating Driver Circuits
Optically coupled PWM signalAdjustable positive and negative drive biasSame circuit works for both power switchesSame PWM signal sent to both switches
-
+ +N1N2
N3
IN
GND
OUT
INGND
OUT
Line 1
Line 2 / N
Gate ref erence
Gate signal
Upper power rail
Lower power rail
Gate control signal
Gate control signal
MOS
Driver-
+ +N1N2
N3
IN
GND
OUT
INGND
OUT
Line 1
Line 2 / N
Gate ref erence
Gate signal
Upper power rail
Lower power rail
Gate control signal
Gate control signal
MOS
Driver
Prototype Hardware
Driver and Power Circuits Test Stand and Load
Same Premise IRMS; PQI Load is Active Only When Needed
-10
-8
-6
-4
-2
0
2
4
6
8
10
curr
ent (
A)
-15
-10
-5
0
5
10
15
curre
nt (A)
PQI Appliance Inactive PQI Appliance Active
Effect of PQI Gain Input
-15
-10
-5
0
5
10
15
curr
ent (
A)
-15
-10
-5
0
5
10
15
curr
ent (
A)
-25
-20
-15
-10
-5
0
5
10
15
20
25
time
curren
t (A)
Too Low Active
Too High
Effect of PQI Load Impedance
-15
-10
-5
0
5
10
15
time
curre
nt (A
)
High Z; Low PQI LoadLow Z; High PQI Load
-15
-10
-5
0
5
10
15
curr
ent (
A)
Conclusions
PQI appliances are an undiscovered opportunitySimple effective circuit designsComparable to, but less expensive than, filtersImprove premise power quality and power factor while performing useful tasks like heating waterTheoretically high effective efficiency
