基于不连续调制的主动热控制以提升并网逆变器类资源的kVA容量限制

The kVA limit of a power electronic converter (PEC) is often limited to keep the junction temperature ($T_{j}$) within a safe operating area (SOA). Hence, controlling $T_{j}$ with advanced algorithms such as active thermal control (ATC) methods seems to be a promising way to increase the kVA limit of PEC. In this regard, this article presents a novel closed-loop control approach, combining the discontinuous pulse width modulation (DPWM) strategy with a system-level current controller. The proposed method enables grid-connected inverter-based resources (IBR) to increase their kVA limit without violating the $T_{j}$ limit. This method further allows the converters to operate at a higher ambient temperature ($T_{\rm amb}$) without sacrificing their power handling capacity. An analytical relationship between the bus clamp angle ($\alpha$) with respect to the switching loss ($P_{\rm sw}$) for DPWM has been explained, which is then used as a control variable for the ATC. For the thermal model, a simple Foster thermal model-based temperature estimation method is described, and its accuracy has been depicted.