Some Power Quality and Electromagnetic Compatibility ...kgh-kongres.rs/images/2016/doc/ppt/108-Buzdugan.pdf · The ferrites obey to the concept of complex magnetic permeability: ...

47th International Congress and Exhibition on Heating, Refrigeration and Air-Conditioning

Belgrade, Sava Centre, 30th November – 2nd December 2016

Some Power Quality and Electromagnetic Compatibility Issues in HVAC Equipment

Mircea Ion Buzdugan

Faculty of Building Services EngineeringTechnical University of Cluj-Napoca, Romania



Motto: Think EMC!

Are Electromagnetic Compatibility and Power Quality dichotomous?

A system is electromagnetically compatible with its environment if it satisfies three criteria:1. It does not cause interference with other systems.2. It is not susceptible to emissions from other systems.3. It does not cause interference with itself.

But what does Power Quality mean?

Two relevant case studies!



Case study no. 1: An air handling unit using two fans driven by brushless DC motors

Schematic diagram of an air handling unit Hardware block diagram Input stage of the drive circuit



Supply voltage and current drawn by the AHU The FFT chart of the harmonic limits of the AHU



Harmonic limits check

Harmonic limits test report for one centrifugal fan

Harmonic limits test report for the air handling unit



The schematic test setup for conducted interference

Conducted interferences of a single BLDC drive in linear scale

Conducted interferences of the AHU in linear scale



Case study no. 2: A residential heating gas central 24 kW

EMI filter of the gas home heating system

The transfer characteristics of the filter indifferential mode

The transfer characteristics of the filter incommon mode

1

2

C D

C D

I I II I I= += −

( )

( )

1 2

1 2

1212

D

C

I I I

I I I

= − = +



RF conducted emissions induced in the public low voltage network by a nearby AM radio broadcasting station

Linear scaleLogarithmic scale



The topology of the power EMI filter

The equivalent circuit of the differential mode filter

The equivalent circuit of the common mode filter

The ferrites obey to the concept of complex magnetic permeability: j′ ′′µ = µ − ⋅µ

0X L ′= ω⋅ ⋅µ 0R L ′′= ω⋅ ⋅µ 2 2Z R X= + tan /′′ ′δ = µ µ



The reactive component of different ferrite materials

The resistive component of different ferrite materials

THE NON-IDEAL BEHAVIOR OF LUMPED COMPONENTS

RESISTORSTransfer function: ( )

2 1

1

ssR EPC ESL EPCH s ESL

sR EPC

+ +⋅ ⋅=+

⋅

Hidden schematics:a. b.

Theoretical Bode plots of the impedance variation with frequency

11

2f

R ECPπ=

⋅first cut-off frequency

12Sf ESL EPCπ

=⋅

self resonant frequency

( ) 2 1s ESL RH s

s ESL EPC sR EPC⋅ +

=⋅ ⋅ + ⋅ +



Magn

itude

(dB)

-50

0

50

100

150

10 4 10 6 10 8 10 10

Phas

e (de

g)

-90

-45

0

45

90

Bode plot of the impedance variation

Frequency (Hz)

Bode plots of the transfer function for a resistor.

Magn

itude

(dB)

-50

0

50

100

150

10 3 10 4 10 5 10 6 10 7

Phas

e (de

g)

-90

-45

0

45

90


Frequency (Hz)

Bode plots of the model from Fig. a. in the relevant range for conducted emissions

Magn

itude

(dB)

-50

0

50

100

10 4 10 5 10 6

Phas

e (de

g)

-90

-45

0


Frequency (Hz)

Bode plots of the model from Fig. b in the relevant range for conducted emissions



CAPACITORSTransfer function: ( )

2 1s ESRsESL ESL CH s ESL

s

⋅+ +

⋅=

Hidden schematics:

a.


self resonant frequency1

2Sf ESL Cπ=

⋅

b.

( ) 1

11

H ss EPC ESR s ESL

sC

−= ⋅ + + ⋅ +



Magn

itude

(dB)

-50

0

50

100

10 3 10 4 10 5 10 6 10 7

Phas

e (de

g)

-90

-45

0

45

90

Bode Diagram

Frequency (Hz)

System: sys

Frequency (Hz): 2.01e+04

Magnitude (dB): -20

Bode plots of the impedance variation with frequency of thecapacitor from Fig. a

Magn

itude

(dB)

-50

0

50

100

150

200

10 3 10 4 10 5 10 6 10 7

Phas

e (de

g)

-90

-45

0

45

90


Frequency (Hz)

System: sys


Magnitude (dB): 191

Bode plots of the impedance variation with frequency of thecapacitor from Fig. b

series resonance frequency 1

ss

ESLC

ωω

⋅ =

parallel resonance frequency1

pp

ESLEPC

ωω

⋅ =⋅



INDUCTORS

Transfer function: ( ) 2

1

1L

sLESRH s ESR

s L EPC s ESR EPC

+=

⋅ + ⋅ ⋅ +( )

11LH s s EPC ESR

sL

− = ⋅ + +

Hidden schematics:a. b.


cut-off frequency 1 2ESRf

Lπ=

self resonant frequency


1p

p

LEPC

ωω

⋅ =⋅


Bode plots of the impedance variation with frequency of theinductor from Fig. a

Magn

itude

(dB)

-50

0

50

100

150

200

10 2 10 4 10 6 10 8 10 10 10 12

Phas

e (de

g)

-135

-90

-45

0

45

90


Frequency (Hz)

System: sys


Magnitude (dB): 150

Bode plots of the impedance variation with frequency of theinductor from Fig. b

Magn

itude

(dB)

0

50

100

150

200

250

10 2 10 4 10 6 10 8 10 10 10 12

Phas

e (de

g)

-90

-45

0

45

90

Bode plot of impedance variation

Frequency (Hz)

System: sys


Magnitude (dB): 236



Equivalent schematics of the common mode choke Equivalent schematics of an EMI filtering cell

The interest in the components’ behavior was focused on the high frequencies where they are to be used to reduceconducted and/or radiated emissions.In order to obtain consistent results, apart from the conventional parameters and stress de-rating factors (powerdissipation, limiting voltage and current, operating temperature range, etc.), one should think also in terms ofnonideal behaviour of the circuit elements in the equivalent model.





EMI filter transfer characteristics in differential mode

EMI filter transfer characteristics in common mode



Final spectrum of RF emissions of the AHU Final spectrum of RF emissions of the gas heating central

Conclusions!



Thank you for your attention!



Some Power Quality and Electromagnetic Compatibility ...kgh-kongres.rs/images/2016/doc/ppt/108-Buzdugan.pdf · The ferrites obey to the concept of complex magnetic permeability: ...

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