# Compact 3 \(\times\) 1 Matrix Converter Module Based on the SiC Devices with Easy Expandability
## 1 Introduction  
The popularity of the matrix converter increased in the last years [1, 2] due to the possible advantages over the standard back-to-back converters (BBC). The improvement in the semiconductor industry, especially in the field of Silicon Carbide (SiC) and Gallium Nitride (GaN) transistors and the small footprint of the component, has opened new ways to build a compact and high-power density matrix converter. The main advantage of the matrix converter is the absence of the storage components (capacitor or inductor), which are getting bulkier if the output power of the standard BBC converter rises. The lack of storage components predetermines the matrix converter to applications with high-power density and it can be used in environments with low or high temperatures (for example, in aerospace applications). The market research shows that commercial products are not available nowadays for use in the matrix converter application. In the past, some power modules were designed and introduced. However, they are not available now due to the shortage of products, and researchers must design their module for the direct matrix converter (DMC) or indirect matrix converter (IMC). For the proper function of the converter, a bidirectional switch is required. The bidirectional switches are built from the discrete transistor in various configurations shown in Figure 1.  
The first device is built from one semiconductor switch and four diodes, where the diode bridge is used. The advantage is that no complex commutation algorithm is required. The main disadvantage is the higher power losses, since the load current flows through three semiconductor devices [3]. The second configuration in Figure 1b, called the common emitter, is widely used due to its good dynamic parameters and lower power losses in comparison to the connection in Figure 1a [3]. The switch in Figure 1c is, from the loss point of view, the same as in Figure 1b but requires less isolated power supplies in the caseof a 3 \(\times\) 3 converter [3; 4]. The CC-switch configuration requires six power supplies, and the CE-switch configuration requires nine power supplies. The CC configuration has worse dynamic parameters due to the big collector parasitic inductance of the components [1]. The last structure is shown in Figure 1d and is represented by the RB-IGBT, which can block voltages in the reverse direction. However, their dynamic behavior in reverse recovery is very slow compared to the standard P-N diode, which can significantly raise the power losses. Because of the slow reverse recovery behavior, these types of switches are not much used in this application currently [5]. The experiments with the relatively new GaN technology show the potential of this technology to be used in future matrix converters applications [6; 7; 8; 9]. These publications show the effort of the researchers to build a compact sample of the bidirectional switch for the matrix converter [10], where authors build an intelligent power switch module with implemented commutation in the module (since every module consists of a microcontroller in which the commutation algorithm is implemented). The next publications show a sample of the low parasitic inductance module based on the SiC chips from the CREE manufacturer [11; 12]. The disadvantage of these modules is that if one device is destroyed, the whole module becomes useless, or the replacement of the broken component can be very expensive. A partial solution is presented in [13], where authors used D2 PAK IGBTs mounted at the PCB in 3 \(\times\) 1 configuration. This arrangement ensures good maintenance and repraability, but using the IGBT transistor leads to higher power losses which cannot be easily dissipated through FR4 substrate. So, additional cooling is required, especially at higher power outputs. Another approach presented by the authors in [14] offers a compact direct matrix converter using the SiC MOSFETs. The sample with a power of 2 kW was built in the PCB with dimensions of 358 \(\times\) 155 \(\times\) 40 mm.