3 phase online ups uninterruptible power supply electrical Circuit knowledge
Provide knowledge of UPS uninterruptible power supply, understand the classification of UPS uninterruptible power supply and UPS electrica Circuit, etc.
the following will learn basic knowledge of uninterruptible power supply
The THDi value of the mains input current can also be reduced by interleaving two three-phase Boost single switch SPWMPFC rectifiers, as shown in Figure 1-1.The idea of this interleaving is to make these two three-phase single switch PFC circuits work as close to the critical state of DCM and CCM as possible, and then…
Comparison of Fixed Switching Frequency and Variable Switching Frequency PFC RectifiersFor convenience, the input current at fixed switching frequency is also represented by phase voltage, that is, M ‘=√ 3M instead of M, as shown in Figure 1-1 From the average value equation of current ia at constant switching frequency and variable switching frequency, the…
In 1993, Ucecla et al. studied the three-phase single switch Boost PFC rectifier controlled by DCM mode variable frequency PWM with variable switching frequency fs. Its circuit is shown in Fig1-1. This is a single switch three-phase PFC rectifier circuit with Boost input inductance L. For the convenience of analysis, it is assumed that: ①…
This site uniformly uses SPWM control technology for introduction for two reasons: one is to facilitate the comparison of different schemes; the other is because it is the most basic control technology. Other control technologies are derived from SPWM control technology. With the development of control theory and functional technology, various microcontrollers with excellent performance…
Switching devices for UPS should be selected based on the following factors: switching frequency, switching capacity, switching voltage and current, etc. The switching frequency should be considered first. Figure 1 shows the capacity range and operating frequency of various switching devices. When making a specific selection, you should first determine the switching frequency of the…
Insulated Gate Bipolar Transistor (IGBT) is a composite power switching device that combines power MOSFET and bipolar power transistor. It not only has the advantages of fast switching speed of MOSFET, high input impedance, low driving power and simple driving circuit, but also the advantages of large capacity and high blocking voltage of high-power bipolar…
Silicon controlled rectifier (SCR), also called thyristor, is the earliest semi-controlled switching device used in power electronics. ①The main parameters of SCR(1) Off-state repetitive peak voltage UDRM.UDRM refers to the maximum off-state pulse voltage with an open gate, the repetition rate is 50 times per second, and the duration of each time is not greater…
Thyristor is also called silicon controlled rectifier (SCR), the following is described as SCR (1) Working conditions of SCR. Because SCR has only two working states of on and off, it has switching characteristics. This characteristic requires certain conditions to be transformed. Such conditions are shown in Table 1. ① When the SCR bears the…
There are two main types of switching devices used in modern UPS, namely Thyristor (SCR) and IGBT. SCR is mainly used in multi-phase phase-controlled rectifiers and bypass switches. Let’s talk about the Thyristor (SCR) Thyristor (SCR), also called silicon controlled rectifier, is the earliest semi-controlled switching device used in power electronics. It is a four-layer…
(1) Characteristics of SPWM modulation waveThe rectifier and inverter in the UPS adopt SPWM control, and the obtained SPWM modulated wave has the following four characteristics.①The SPWM modulation waveform can be turned into a numerically stable quasi-sine wave waveform②By moving the phase of the sinusoidal modulation wave us, the phase of the SPWM modulation wave…