The interface with the DC bus is performed with a boost converter and two bidirectional boost converters, which are regulated using classical PI controllers. This HESS has a power management strategy designed to reduce the dynamic stress of the battery, provide a stable DC voltage, prevent a deep battery discharge, and enhance the overall efficiency of the system. The tuning process of these PI controllers is performed with different methods: pole placement, linear matrix inequalities (LMIs), particle swarm optimization (PSO), and genetic algorithm (GA). Then, the performances of the PI controllers, under several scenarios and with different tuning methods, are compared in Matlab/Simulink only. Simulations and experimental comparisons of the three HESS types are reported in [6]. The tested HESSs are formed by a PV panel, a battery, and an SC using bidirectional boost converters, where the primary controllers are classical PI, with reference currents obtained from a second-level power flow control. Another HESS formed by batteries and lithium-ion capacitors (LiCs) is reported in [24], where the semi-active configuration is used. In this case, the battery is connected to a DC bus, and the LiC current is controlled by a non-specified bidirectional DC/DC converter. A power flow controller in the second level sets the battery current, which is regulated using a classical PI acting on the power converter. Finally, the validation of this HESS is carried out using an advanced vehicle simulation platform. Similar to the previous work, in [25] is used a non-specified bidirectional DC/DC converter to form a semi-active HESS based on a battery and a supercapacitor. This HESS is controlled using a hysteresis control algorithm, where its reference is generated by an optimizer based on both fuzzy logic and model predictive controllers. Unfortunately, the dynamic performance of the controllers is not evaluated. Another hysteresis control for HESS is reported in [26], where the battery SoC and the supercapacitor SoV (state of voltage) are used to control a bidirectional boost converter. This solution reduces the battery discharge percentage and improves the system's efficiency by stabilizing the DC bus voltage. Typically, the HESS control strategy consists of distributing the power between the storage devices, and thus it is mainly an energy management system (EMS). A well-designed control strategy will use the complementary features of the ESS forming the HESS, allocating the low-frequency power demand to the device of high energy density. Similarly, the high-power density device must to attend the short-time peaks, i.e., the high-frequency power profile. There are multiple EMSs for HESSs reported in the literature, which can be divided into three main categories: rule-based control strategies, optimization-based control strategies, and intelligence-based control strategies [27]. In summary, the previous literature review shows that bidirectional boost converters are commonly used in HESS systems to connect the supercapacitor with the battery or DC bus [6; 21; 22; 23; 26]. This selection is based on the simplicity of the bidirectional boost topology; however, this topology introduces two major limitations: first, the supercapacitor voltage must be lower than the battery or DC bus voltage, which limits the commercial supercapacitors and batteries that can be used to form the HESS; and, second, the supercapacitor boost converter provides a discontinuous current to the battery, which introduces high-frequency current harmonics that could produce heating and damages. The literature revision also shows that classical PI controllers are widely used to regulate the supercapacitor converter [6; 21; 23; 24], which must be designed around a particular operation condition. Therefore, such a solution makes it impossible to ensure the desired performance (and even global stability) in a wide operation range.