**3.2 Input voltage reference (IVR) technique**

The voltage across small input filter capacitor is measured and compared to the MC supply voltage to generate gate drive signal for RCC of IPC method as shown in **Figure 8**.

The IVR technique can be used to detect the regeneration in the matrix converter for electrical braking methods. The duty cycle variation is directly proportional to the increase in the line to line voltage across the input filter capacitor of the matrix converter under regeneration with respect to the output power (Po), as shown in Eq. (5).

$$\mathbf{V\_{AB}} \propto P\_o \propto D \tag{5}$$

**61**

**Figure 9.**

*Bidirectional switch (BDS) method.*

*Matrix Converter for More Electric Aircraft DOI: http://dx.doi.org/10.5772/intechopen.81056*

1.Bidirectional switch (BDS) method

2.Input power clamp (IPC) method

**4.1 Bidirectional switch (BDS) method**

3.Standard clamp circuit (SCC) method

regeneration takes place in the MC motor drive.

**4.2 Input power clamp (IPC) method**

investigated:

**4. Methods for avoiding regeneration in matrix converter**

To avoid regeneration in matrix converters, three novel circuit topologies are

The power circuit for the BDS method [18], regeneration control circuit (RCC) or electrical braking circuit, is shown in **Figure 9**. The regeneration control circuit (RCC) is introduced across the input filter capacitors (CAB, CBC, and CAC). The regeneration control circuit (RCC) is responsible for power dissipation when

The RCC consists of three bidirectional switches (BDSAB, BDSBC, and BDSAC) in series with three resistors (RAB, RBC, and RAC) connected across the input lines, in parallel with the input filter capacitor. The schematic of the regeneration control

The input power clamp (IPC) method [19] is used for braking the electrical energy in a matrix converter motor drive. The IPC method requires only one braking resistor and a UDS, as shown in **Figure 10**, when compared to the BDS method, which requires three switches in series with three resistors. Electrical braking circuit or regeneration control circuit (RCC) for the input power clamp (IPC) method

circuit (RCC) or electrical braking circuit (EPC) is depicted in **Figure 9**.

Here, *VAB* is line voltage across small input filter capacitor.

The RCC is turned on only if any voltage difference is detected between MC supply voltage and voltage across the small input filter capacitor for each sampling period. In addition, if the small input filter capacitor voltage is equal to the MC supply voltage, then the duty cycle is set to zero. Gate drive signal is generated using FPGA and DSP control platform similar to PC technique. The power dissipation through RCC happens only if the MC drive is operating under regenerative mode.

*Aerospace Engineering*

**Figure 8**.

shown in Eq. (5).

regenerative mode.

power. The MC drive is not capable to output whole of regenerated power because of it losses such as friction, windage, iron, switching and conduction losses. Because of above reason, the braking resistor dissipates less than the actually regenerated power. As written in Eqs. (3) and (4), the design of braking resistor

Ib = Vin/Rb (4)

where the braking current (Ib) and input power (Pin,max) are directly proportional to the input voltage. The braking resistor design also depends on the braking time, thermal capacity of the resistor, and heat sink. And the current rating of UDS/

The voltage across small input filter capacitor is measured and compared to the MC supply voltage to generate gate drive signal for RCC of IPC method as shown in

The IVR technique can be used to detect the regeneration in the matrix converter for electrical braking methods. The duty cycle variation is directly proportional to the increase in the line to line voltage across the input filter capacitor of the matrix converter under regeneration with respect to the output power (Po), as

VAB ∝ Po ∝ D (5)

The RCC is turned on only if any voltage difference is detected between MC supply voltage and voltage across the small input filter capacitor for each sampling period. In addition, if the small input filter capacitor voltage is equal to the MC supply voltage, then the duty cycle is set to zero. Gate drive signal is generated using FPGA and DSP control platform similar to PC technique. The power dissipation through RCC happens only if the MC drive is operating under

Here, *VAB* is line voltage across small input filter capacitor.

*Block diagram of the input voltage reference (IVR) technique for IPC method.*

2

/Rb (3)

(Rb) relies on maximum regenerative power during regeneration.

Pin,max = Vin

BDS in RCC must be higher than the braking current.

**3.2 Input voltage reference (IVR) technique**

**60**

**Figure 8.**
