Abstract — The evolution of technology in the field of

power electronics has been very evident in recent years,

including the development of new semiconductors that are

prepared to operate in systems with high working voltage,

as in the case of ultra high voltage device.

On the other hand, there has also been a large

development in high-frequency transformers, in particular

ferromagnetic alloys that promote a high saturation flux

density, that means a high power density as well as lower

losses ensuring good efficiency of the transformer.

This paper proposes a high frequency power transformer

for applications in power systems, that is, beyond the

reduction / increase of voltage levels and galvanic isolation

garnished by the classic transformer, the proposed

transformer allows many other features such as: large

capacity control, lower volume of the transformer core,

good performance against voltage fluctuations.

This transformer is designated Solid State Transformer,

and it is composed of a Modular Matrix Converter, a Three

Phase Matrix Converter and High Frequency Transformer.

The SST allows to obtain a system of adjustable output

voltage under load, not only in amplitude but also in

frequency.

The Modular Matrix Converter was designed during the

course of the dissertation. In addition to being able to

operate in MV systems, it also enables the unsaturation of

the transformer.

Index Terms — Solid State Transformer; High Frequency

Transformer; Matrix Converter; Space Vector

Modulation; Voltage Regulator; Current Regulator

I. INTRODUCTION

owadays power transformers are essential devices in the

power distribution system. The widespread use of this

device has resulted in a cheap, efficient, reliable and mature

technology and any increase in performance are marginal and

come at great cost [1]. Despite their great utility, they present

some disadvantages such as [2]:

1. Bulky size and heavy weight

2. Transformer oil can be harmful when exposed to the

environment

3. Core saturation produces harmonics, which results in

large inrush currents

4. Unwanted characteristics on the input side, such as

voltage dips, are represented in output waveform

5. Sensitivity to the harmonics of the output current

6. Voltage regulation inefficient

In 1980, researcher James Brooks implemented the first

prototype of the SST. Due to major technological limitations at

the time he had little success. However, after a few years, the

concept of SST developed, with different architectures and

topologies, and in the last 10 years, the architecture and

topology of SST has been adapted to enable new applications,

especially in energy systems.

In recent years, interest in Solid State Transformers has

grown so much that in 2010 the SST technology was named by

MIT "Massachusetts" Institute of Technology ", as one of the

technologies greater relevance in future power distribution

systems. In recent years, many researchers have been studying

new applications of SST, resulting in different architectures and

topologies, which are associated with different applications [3].

VAC VACThree-phase Matrix

Converter

High Frequency Transformer

50/60Hz 50/60HzHigh Frequency> 1kHz

Modular Matrix Converter

Figure 1 – SST Concept

The Solid State Transformer (SST) provides an alternative to

the Low Frequency Transformer (LFT). The proposed SST is

presented in Figure 1 is based on one three phase High

Frequency Transformer supported by power electronic

converters. The input is connected with a Modular Matrix

Converter with an innovative feature that guarantees the non-

saturation of the HFT. Given the voltages applied to the SST,

and the limitations of the used semiconductor, has been

designed a modular matrix converter, which ensures that each

semiconductor support a small fraction of the maximum system

voltage. Thus, it is possible to ensure that the maximum voltage

applied to the semiconductor never exceeds the maximum

allowable values.

Electronic Power Transformer for Applications

in Power Systems

Electronic Power Transformer for Applications

in Power Systems

Pedro Miguel Costa Fernandes

Department of Electrical and Computer Engineering

Instituto Superior Técnico - Technical University of Lisbon, Portugal

Email: Pedro.c.fernandes@tecnico.ulisboa.pt

N

The output is connected with a three phase Matrix Converter

controlled by Space Vector Modulation (SVM).

II. SOLID STATE TRANSFORMER (SST)

A. Modular Matrix Converter

The modular matrix converter consists of single-phase

matrix converters in series, ensuring that the maximum voltage

applied to the semiconductors is compatible with existing

semiconductors in the market. Thus, it is possible to preserve

the proper operation thereof (Figure 3)

Figure 3 - Simplified scheme of the association in series of single-

phase matrix converters

B. Single-Phase Matrix Converter

The single-phase matrix converter consists of four

bidirectional switches fully controlled, allowing the

interconnection of two single-phase systems, one with

characteristics of voltage source and another with

characteristics of current source (Figure 4).

Assuming that the bidirectional semiconductor switches have

an ideal behaviour (zero voltage when they are ON, zero

leakage current when they are OFF and nearly zero switching

time), and each of the switches can be represented

mathematically by a variable 𝑆𝑘𝑗 which can take the value of

"1" if the switch is closed (ON) and the value of "0" if the switch

is open (OFF).

One can represent the state of the converter in a 2x2 matrix

(1).

S11

Va

Vb

Ia

Ib

S12

S21

S22

VA VB

IA IB

Figure 4 – Single-Phase Matrix Converter

Input Filter

Output FilterThree-phase Matrix Converter

Load

Modular Matrix Converter

High Frequency Transfomer

Figure 2 - Simplified schematic of the SST model

We must take into account compliance with the topological

constraints, implying that in each time step, each phase output

is only connected to one and only one input phase.

𝑺 = [𝑆11 𝑆12𝑆21 𝑆22

] (1)

In Table I are described four possible states, with the

respective correlations between the electrical variable

combinations.

Table I – Possible switch combination for a Single-Phase

Converter

Stat

e

Si11 Si12 Si21 Si22 VA VB iA iB

1 1 0 0 1 Va Vb IA IB

2 0 1 1 0 Vb Va IB IA

3 1 0 1 0 Va Va 0 0

4 0 1 0 1 Vb Vb 0 0

C. Three Phase Matrix Converter

The three-phase Matrix Converter, which is represented in

Figure 5. It consists of nine controlled bidirectional switches

making a 3x3 matrix (2) that allows a connection between two

three-phase systems; the input with voltage source

characteristics and the output system with characteristics of

current source. These converters allow direct AC-AC

conversion, without an intermediate but with a high efficiency

guaranty.

By assuming ideal semiconductors, each switch can be

mathematical represented by 𝑺𝒌𝒋 = 1, 𝑘 ∈ {1,2,3}, a binary

variable with two possible states: “𝑺𝒌𝒋 = 1” if the switch is ON,

and “𝑺𝒌𝒋 = 0” if it OFF. Due to electrical limitations of the MC

topology, each line of the matrix can only have one switch “ON.

(2)

𝑺 = [

𝑆11 𝑆12 𝑆13𝑆21 𝑆22 𝑆23𝑆31 𝑆32 𝑆33

] ∑𝑺𝑘𝑗 = 1, 𝑘 ∈ {1,2,3}

3

𝑗=1

(2)

S11

Va

Vb

Vc

Ia

Ib

Ic

S12

S13

S21 S31

S22 S32

S13 S13

IA IB IC

VA VB VC Figure 5 – Three-Phase Matrix Converter

The S matrix represents the states of the switches and enables

a mathematical correlation between the line-to-neutral output

voltages VA, VB, VC and the line-to-neutral input voltages Va,

Vb, Vc. Still, the transpose of matrix S correlates the input

currents ia, ib, ic with the output currents (3).

[

𝑉𝐴𝑉𝐵𝑉𝐶

] = 𝑺 [

𝑉𝑎𝑉𝑏𝑉𝐶

] [

𝐼𝑎𝐼𝑏𝐼𝑐

] = 𝑺𝑻 [

𝐼𝐴𝐼𝐵𝐼𝐶

] (3)

Finally, the three-phase Matrix Converter has now 27 possible

combinations to represent the input currents and output

voltages.

D. SVM – Space Vector Modulation

SVM approach, including Indirect SVM and Direct SVM

proposed in [4] and [5] were often used in MC for it’s

appropriate in operation. Conventional SVM approach is used

to synchronize the input voltage by zero cross detecting of the

input phase voltage, which can be seen in Figure 6 a), and

assuming a balanced input voltage in rated value.

Figure 6 b) c) shows MC’s output voltage space vectors and

output voltage synthesis, where 0, I, II, III, IV, V and VI stand

for six vector sectors, and V1-V6 stand for active voltage vector,

V0 and V7 stand for zero.

Zona 1

3 5 1 2 4 6

+Vmax

-Vmax

θv

rad

Zona 2 Zona 3 Zona 4 Zona 5 Zona 6 Zona 1

a)

1

V1(D, C, C)

V2(D, D, C)

V3(C, D, C)

V4(C, D, D)

V5(C, C, D)

V6(D, C, D)

V7(C, C, C), V8(D, D, D)

III II

V VI

IV IV0

θv

Vβ

Vα

V0refαβ V7 V8

d0V0θv

π/3

dα Vα

dβ Vβ

b) c)

Figure 6 - Line-to-line output voltage sectors; b) Space location of

vectors V0 to V7, defining 6 sectors in the αβ plane; c) Representation

of the synthesis process of 𝑉𝑜𝑟𝑒𝑓𝛼𝛽 using the space vectors adjacent to

the sector where the reference vector is located.

With access to the adjacent space vectors 𝑉𝛼 , 𝑉𝛽 and

𝑉0 shown in Figure 6 c) obtains the voltage vector 𝑉𝑜𝑟𝑒𝑓𝛼𝛽 ,

wherein the duty cycle associated with each of these vectors are

𝑑𝛼, 𝑑𝛽 and 𝑑𝑜.

Theoretically, assuming that the switching frequency is much

higher than the input frequency f0 >> fs, it is possible for each

commutation period to define the reference vector 𝑉𝑜𝑟𝑒𝑓𝛼𝛽 as

(4).

𝑉𝑜𝑟𝑒𝑓𝛼𝛽 ≈ 𝑉𝛼𝑑𝛼 + 𝑉𝛽𝑑𝛽 + 𝑉0𝑑𝑜 (4)

The reference vector 𝑉𝑜𝑟𝑒𝑓𝛼𝛽 (5) of the line-to-line output

voltage describes a circular trajectory in the plane αβ and is

synthesized using the space vectors represented in Figure 6 c).

𝑉𝑜𝑟𝑒𝑓𝛼𝛽(𝑡) = √3 𝑉𝑜𝑐 𝑒𝑗𝜔𝑜𝑡 =

√3

2 𝑉𝑜𝑐𝑚𝑎𝑥 𝑒

𝑗𝜔𝑜𝑡 (5)

The maximum of the output voltage reference (5) can achieve

the same voltage is imposed VDC will output rectifier.

Therefore, we can conclude that the output voltage of the

rectifier/inverter model is limited by the rectifier.

Additionally, similar procedure is implemented for the MC

rectifier stage, which leads to nine active vectors. It is assumed

that the adjacent vectors I1-I6 are Iδ, Iϒ and zero vectors I7, I8 and

I9 with the respective duty cycles dδ (for Iδ), dϒ (for Iϒ) and d0

(for one of the zero vector).

Considering that the switching frequency is much higher than

the input frequency fs>>fi, it is possible for each commutation

period to define the reference vector 𝐼𝑖𝑟𝑒𝑓𝛼𝛽 as (6).

𝐼𝑖𝑟𝑒𝑓𝛼𝛽 ≈ 𝐼𝛾𝑑𝛾 + 𝐼𝛿𝑑𝛿 + 𝐼0𝑑0 (6)

From [4] and [5] the duty cycles dδ, dϒ and d0 can be

calculated by using a trigonometric analysis.

The rectifier stage requires two non-zero vectors to the

modulation of the input current of the inverter stage which takes

two non-zero vectors to the modulation of the output voltage,

thus resulting modulation will require four non-zero vectors and

null vector. For the modulation of the input current and the

output voltage, the switching time (7) for each vector is

obtained by multiplying the cycle factors obtained for the

rectifier and the inverter [6].

{

𝑑𝛾𝑑𝛼 = 𝑚𝑐 𝑚𝑣 sin (

𝜋

3 − 𝜃𝑖) sin (

𝜋

3 − 𝜃𝑣)

𝑑𝛾𝑑𝛽 = 𝑚𝑐 𝑚𝑣 sin ( 𝜋

3 − 𝜃𝑖) sin ( 𝜃𝑣)

𝑑𝛿𝑑𝛼 = 𝑚𝑐𝑚𝑣 sin(𝜃𝑖) sin ( 𝜋

3 − 𝜃𝑣)

𝑑𝛿𝑑𝛽 = 𝑚𝑐𝑚𝑣 sin( 𝜃𝑖) sin( 𝜃𝑣)

𝑑0 = 1 − 𝑑𝛾𝑑𝛼 − 𝑑𝛾𝑑𝛽 − 𝑑𝛿𝑑𝛼 − 𝑑𝛿𝑑𝛽

(7)

After setting the duty cycles (7), it is necessary to determine

the order in which the vectors should be applied to the matrix

converter ensuring control of output voltage and input current.

The selection of vectors to be applied shall be governed by

some priorities, such as minimizing harmonic distortion of the

input current or minimize the number of commutations of the

switches [7].

The choice of vectors to use depends on the location of the

sector composed of the reference voltage output and the sector

location of the input current. Based on these conditions, it

becomes possible to identify the vectors to be used in the

modulation process (Table II).

Table II - Matrix Converter’s vectors used in the modulation of

line-to-line output voltages and input currents

V0 Ii dϒdα dϒ dβ dδ dα dδ dβ V0 Ii dϒ dα dϒ dβ dδ dα dδ dβ

1

1 -4 +1 +6 -3

4

1 +4 -1 -6 +3

2 +6 -3 -5 +2 2 -6 +3 +5 -2

3 -5 +2 +4 -1 3 +5 -2 -4 +1

4 +4 -1 -6 +3 4 -4 +1 +6 -3

5 -6 +3 +5 -2 5 +6 -3 -5 +2

6 +5 -2 -4 +1 6 -5 +2 +4 -1

2

1 +1 -7 -3 +9

5

1 -1 +7 +3 -9

2 -3 +9 +2 -8 2 +3 -9 -2 +8

3 +2 -8 -1 +7 3 -2 +8 +1 -7

4 -1 +7 +3 -9 4 +1 -7 -3 +9

5 +3 -9 -2 +8 5 -3 +9 +2 -8

6 -2 +8 +1 -7 6 +2 -8 -1 +7

3

1 -7 +4 +9 -6

6

1 +7 -4 -9 +6

2 +9 -6 -8 +5 2 -9 +6 +8 -5

3 -8 +5 +7 -4 3 +8 -5 -7 +4

4 +7 -4 -9 +6 4 -7 +4 +9 -6

5 -9 +6 +8 -5 5 +9 -6 -8 +5

6 +8 -5 -7 +4 6 -8 +5 +7 -4

The duty cycle used in the modulation process of the matrix

converter are calculated based on the output voltages and input

current reference (7). In order to know the action time of the

vectors, was used a technique that compares a triangular carrier

according to signals from the duty cycle. (Figure 7).

dϒ dα

dϒ dβ

dδ dα

dδ dβ

d0 dϒ dα

dϒ dβ

dδ dα

dδ dβ

dϒ dα

dϒ dβ

dδ dα

dδ dβ

d0 dϒ dα

dϒ dβ

dδ dα

dδ dβ

Du

ty C

ycle

Sig

na

ls

Time

Figure 7 - Modulation process used to select the space vectors and

the time interval when they are applied

The selection of vectors to be applied in the control of matrix

converter is not only based on the analysis of Figure 7 but also

in Table II.

Figure 7 show the driving time of each vector. This

information together with the location of the input current and

the output voltage follows for Table II, from which the result

vectors to be applied to three-phase matrix converter switches.

The Figure 8 is a simplified way of obtaining the final vector

to apply to the matrix converter.

dϒ dα

dϒ dβ

dδ dα

dδ dβ

d0 dϒ dα

dϒ dβ

dδ dα

dδ dβ

dϒ dα

dϒ dβ

dδ dα

dδ dβ

d0 dϒ dα

dϒ dβ

dδ dα

dδ dβ

Du

ty C

ycle

Sig

na

ls

Tempo

S11

Va

Vb

Vc

Ia

Ib

Ic

S12

S13

S21 S31

S22 S32

S13 S13

IA IB IC

VA VB VC

Tdϒ dα Vector -4

Input current LocationOutput Voltage

Location

1 1

Figure 8 - Selection scheme for the SVM vectors

SST proposed in this paper, the modulation method must be

modified to ensure non-saturation of the high frequency

transformer.

E. Modified SVM

Modified SVM is a switching a strategy based on SVM that

to ensure non-saturation of transformer. Figure 9 represents the

modulation process already used with appropriate

modifications to prevent saturation of the transformer.

III. CONTROL OF THE OUTPUT CURRENT

The current regulator block diagram is show in Figure 8,

where 𝐼𝑜𝑑𝑞𝑟𝑒𝑓 is the reference current and 𝐼𝑜𝑑𝑞 the load current.

Both are multiplied by αi, the current sensor gain, and the

difference between the two currents, i.e., the current error is

applied to the controller Ci(s). This controller generates the

modulating voltage used by the SVM.

LoadHdq V0dq I0dq

αi

αi

I0dq ref

+ -

Figure 8 – Output current regulator block diagram

C(s) is a Proportional-Integral (PI) Controller, which

ensures a dynamic second order closed chain. This

compensator ensures a null static error and an acceptable rise

time.

For the sizing of the current regulator, the three-phase matrix

converter can be represented as transfer function of the first

order (8) with a given delay time Td.

𝐺(𝑠) =1

1 + 𝑠 𝑇𝑑 (8)

To calculate the Tz and Tp parameters, it is considered that

the zero of C (s) cancels the lowest frequency pole, introduced

by the output filter. From (9), one obtains Tz where Rout is the

sum of the internal resistance of the coil with the load

resistance.

𝑇𝑧 = 𝐿𝑜𝑢𝑡𝑅𝑜𝑢𝑡

(9)

The value of Tp is calculated by (10), where αi is the current

gain and Td is the average delay of the system.

𝑇𝑝 = 2 𝛼𝑖 𝑇𝑑𝑅𝑜𝑢𝑡

(10)

Three-Phase Matrix ConverterModular Matrix Converter

1 2 3 4

Signal Modified SVM

High Frequency Transformer

Gate

Gate

SVM+1

-1

Figure 9 – Modified SVM

IV. CONTROL OF THE OUTPUT VOLTAGE

In sizing the voltage controller, care has based on this single-

line diagram in Figure 9.

System

ISystem ILoad

ic

VLoadCf1

Figure 9- Load voltage regulator

The voltage regulator has to ensure that the load voltage,

which is the same as the capacitor voltage (11).

𝑉𝐿𝑜𝑎𝑑 = 𝑖𝑐𝑠𝐶𝑓1

(11)

In the design of the controller, it is considered that the load

current (Iload) is a disturbance of the system [8], [9]. As the

current output of the matrix converters is controlled, it is also

possible to consider that the matrix converters, filters and

transformer leakage inductances can be represented by the

current source Isystem.

In Figure 10 is presented the voltage regulator block diagram,

wherein the block

𝐺𝑖𝛼𝑖⁄

𝑠𝑇𝑑+1 represents the matrix converter

controlled by current, [10].

Iref matrix Iline VLoad

αv

αv

VLoad ref

+ -

ILoad

+

- Ic

Figure 10 – Block diagram of the voltage regulator

Finally, the proportional gain Kp and the integral gain Ki are

obtain by (12):

{

𝐾𝑝 =

2.15𝐶𝑓1𝛼𝑖

𝛼𝑣𝑇𝑑(1.75)2

𝐾𝑖 =𝐶𝑓1 𝛼𝑖

𝛼𝑣𝑇𝑑2(1.75)3

(12)

V. RESULTS

The SST developed in this dissertation was implemented in

MATLAB / Simulink software in order to evaluate and test the

performance and robustness in several operating scenarios.

A. Scenario 1 – Ideal conditions

In the first scenario is take analysis of the system before

normal operation without any disruption in the network.

In this dissertation was used High frequency transformer

with a power of 630KVA with a working frequency of 2000Hz

In Figure 11 and Figure 12 are shown the waveforms of the

voltage in the load as well as the respective current.

The waves have a sinusoidal forms with a fundamental

frequency of 50Hz.

Figure 11 – Line to-neutral load voltage

Figure 12 – Load current

In Figure 13 was compared the reference voltage with the

control voltage, and conclude that the reference tracking is

achieved with a greatly reduce error.

Figure 13- Line-to neutral load reference voltage (Red), and line-

to-neutral load voltage (Blue))

Figure 14 – Error between in reference voltage and control

voltage.

0.25 0.255 0.26 0.265 0.27 0.275 0.28 0.285 0.29-400

-300

-200

-100

0

100

200

300

400

Tens

ão [V

]

Tempo [s]

0.25 0.255 0.26 0.265 0.27 0.275 0.28 0.285 0.29-400

-300

-200

-100

0

100

200

300

400

Corre

nte

[A]

Tempo [s]

0.25 0.255 0.26 0.265 0.27 0.275 0.28 0.285 0.29-400

-300

-200

-100

0

100

200

300

400

Tens

ão [V

]

Tempo [s]

0.21 0.22 0.23 0.24 0.25 0.26 0.27 0.28 0.29-3

-2

-1

0

1

2

3

Tens

ão [V

]

Tempo [s]

Figure 15 represents the output voltage of the modular matrix

converter, applied to a primary winding.

Figure 16 represents the input voltage of the three-phase

converter.

Figure 15 – Voltage applied to a primary winding of transformer

Figure 16 - Voltage applied to a secondary winding of transformer

Figure 17 represents the input currents of SST. The currents

contais the high frequency harmonics arising from the high-

frequency semiconductor switching converters.

Figure 17 – Input currents of SST (MV)

B. Scenario 2 – Voltage sag

In this section it was the behavior of the SST when

confronted with a voltage sag on the medium voltage.

In Figure 18 can check the wave disturbance in the input

voltage. The perturbance caused a lowering in input voltage

during two periods of the network.

Figure 18 – Medium voltage.

Figure 19 represents the load voltage, and it can be concluded

that the voltage suffered no change.

Figure 19 – Load voltage

In Figure 20 was compared the reference voltage with the

control voltage, and conclude that the reference tracking is

achieved with a greatly reduce error.

Figure 20 - Line-to neutral load reference voltage (Red), and line-

to-neutral load voltage (Blue))

C. Scenario 2 – Voltage swell

In this section, the behavior of the SST was evaluated for a

voltage swell on the medium voltage.

In Figure 21 it can be seen the wave disturbance in the input

voltage. The disturbance caused a substantial increase in the

input voltage during two periods of the grid.

0.02 0.022 0.024 0.026 0.028 0.03 0.032 0.034 0.036 0.038 0.04-5000

-4000

-3000

-2000

-1000

0

1000

2000

3000

4000

5000

Tens

ão [V

]

T [s]

0.02 0.022 0.024 0.026 0.028 0.03 0.032 0.034 0.036 0.038 0.04-600

-400

-200

0

200

400

600

Tens

ão [V

]

T [s]

0.25 0.255 0.26 0.265 0.27 0.275 0.28 0.285 0.29-100

-80

-60

-40

-20

0

20

40

60

80

100

Corre

nte

[A]

Tempo [s]

0.16 0.18 0.2 0.22 0.24 0.26 0.28-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1x 10

4

Tens

ão [V

]

Tempo [s]

0.16 0.18 0.2 0.22 0.24 0.26 0.28-400

-300

-200

-100

0

100

200

300

400

Tens

ão [V

]

Tempo [s]

0.16 0.18 0.2 0.22 0.24 0.26 0.28-400

-300

-200

-100

0

100

200

300

400

Tens

ão [V

]

Tempo [s]

Figure 21 – Medium voltage

Figure 22 the sinusoidal load voltage. Faced with an voltage

swell at the entrance of the SST, the waveforms of voltages

underwent no significant changes, which shows the good

response of the SST.

Figure 22 – Load voltage

In Figure 23 was compared the reference voltage with the

control voltage, and conclude that the reference tracking is

achieved with a greatly reduce error

Figure 23 - Line-to neutral load reference voltage (Red), and line-

to-neutral load voltage (Blue))

D. Scenario 3 – Harmonic Distortion on the medium

voltage

In this operating scenario, consider the existence of

harmonics of the medium voltage. In the test scenario is

considered the 5th harmonic, ensuring that its amplitude does

not exceed the threshold of 6% set by the standard (EN 50160).

In Figure 24 is represented the wave of the input voltage in

SST. There is the effect of the 5th harmonic, responsible for

wave distortion of the input voltage.

Figure 24 – Medium voltage

The voltage at the load (Figure 25) shows a nearly sinusoidal

wave with a small ripple.

Figure 25 – Load voltage

VI. CONCLUSIONS AND FUTURE WORK

This work aimed to develop a electronic power transformer

for distribution systems, capable of producing voltages of

variable magnitude and frequency at the output.

During the development of this project, emerged several

concerns, such as non-saturation of the transformer, that with

the change in the characteristics of the modulation SVM was

achieved. Another major concern is the limited voltage imposed

by semiconductor constituting the matrix converters, not

facilitating the integration of the matrix converter in the

medium-voltage side.

Known the problem, we developed a modular matrix

converter, which regulates the voltage to levels that do not cast

doubt on the operability of used converters.

The current controller, based in PI controller, was tested with

a good performance, with a static error close to zero, and

allowing a quick response while ensuring system stability for

various load scenarios. The power factor might not be unitary

since it depends on the input filter and the load conditions.

Finally, it is important to note that this system has many other

utilities that may be developed in the near future, such as

integration into a smart grid or in substations fitted to renewable

energy systems.

REFERENCES

[1] van der Merwe, J., W.; du T. Mouton, H.; “The solid-state transformer

concept: A new era in power distribution,” in AFRICON 2009, 2009;

[2] Hassan, R.; Radman, G.; "Survey on Smart Grid" IEEE 2010

SoutheastCon, Proceedings of the power electronic application

0.16 0.18 0.2 0.22 0.24 0.26 0.28

-1

-0.5

0

0.5

1

x 104

Tens

ão [V

]

Tempo [s]

0.16 0.18 0.2 0.22 0.24 0.26 0.28-400

-300

-200

-100

0

100

200

300

400

Tens

ão [V

]

Tempo [s]

0.16 0.18 0.2 0.22 0.24 0.26 0.28-400

-300

-200

-100

0

100

200

300

400

Tens

ão [V

]

Tempo [s]

0.25 0.255 0.26 0.265 0.27 0.275 0.28 0.285 0.29-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1x 10

4

Tens

ão [V

]

Tempo [s]

0.25 0.255 0.26 0.265 0.27 0.275 0.28 0.285 0.29-400

-300

-200

-100

0

100

200

300

400

Tens

ão [V

]

Tempo [s]

conference, vol., no., pp.210–213, March 2010;

[3] She, X.; “Review of Solid-State Transformer Technologies and Their

Application in Power Distribution Systems”, Future Renewable Electr.

Energy Delivery & Manage. Syst. Center, North Carolina State Univ.,

2013;

[4] Huber, L., Borojevic, D., Burany, N., Analysis, Design and

Implementation of the Space-Vector Modulator for Forced- Commutated

Cycloconverters; IEE Proceedings-B Electric Power Applications, vol

139, No 2, March 1992;

[5] Nielsen, P.; Blaabjerg, F.; Pedersen, J.; “Space-Vector Modulated Matrix

Converter with Minimized number of Switchings and a Feedforward

Compensation of Input Voltage Unbalance”; Proc. PEDES’96

Conference, Vol. 2, pp. 833-839, New Delhi, India.

[6] Huber, L.; Borojevic, D.; “Space Vector Modulated Three-Phase to

Three-Phase Matrix Converter with Input Power Factor Correction”;

IEEE Transactions on Industry Applications, Vol. 31, No 6, pp. 1234 -

1246, November/December 1995.

[7] Nielsen, P.; Blaabjerg, F.; Pedersen, J.; “Space-Vector Modulated Matrix

Converter with Minimized number of Switchings and a Feedforward

Compensation of Input Voltage Unbalance”; Proc. PEDES’96

Conference, Vol. 2, pp. 833-839, New Delhi, India.

[8] Pinto, S., Silva, J. F., Silva, F., Frade, P., Design of a Virtual Lab to

Evaluate and Mitigate Power Quality Problems Introduced by

Microgeneration, in “Electrical Generation and Distribution Systems and

Power Quality Disturbances, Intech, 2011.

[9] Alcaria, P, Pinto, S. F., Silva, J. F., Active Voltage Regulators for Low

Voltage Distribution Grids: the Matrix Converter Solution, Proc. 4th

International Conference on Power Engineering, Energy and Electrical

Drives, PowerEng 2013, pp 989-994, Istanbul, Turkey, May 2013.

[10] Pinto, S.; Silva, J.; Gambôa, P.; “Current Control of a Venturini Based

Matrix Converter”, IEEE International Symposium on Industrial

Electronics – ISIE 2006, Vol. 4, pp. 3214 – 3219, Montréal, Canada, July

2006.