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 IGBT three-phase SPWM inverter
The cascade superposition of independent DC power supply is realized by using the unidirectional conductivity of superposition diode. Its principle circuit includes (a) the main circuit and (b) the control circuit. (a) In, E1 ~ en are n independent DC power supplies, S1 ~ Sn are superposition control switches, VD1 ~ vdn are superposition diodes,…
There are two types of existing SPWM multilevel inverters: one is a clamped multilevel inverter (including diode clamping, capacitor clamping and hybrid clamping multilevel inverters), which are typically The control method is the carrier triangular wave stacked SPWM control method; the other is the H-bridge cascaded multi-level inverter, and its typical control method is the…
For large-capacity three-phase UPS, a high-power three-phase SPWM inverter needs to be selected. Due to the substantial improvement of the power level, new requirements are put forward for the structure of the three-phase SPWM inverter. Using a single-phase full-bridge inverter (2H bridge) as a bridge arm of a three-phase SPWM inverter is one of the…
The voltage space phasor pulse width control technology of the three-phase four-leg inverter, namely the three-phase four-leg VSV-PWM inverter, will be introduced. The main circuit of the three-phase four-arm inverter is shown in Figure 1. It is composed of a three-phase half-bridge inverter and a bridge arm formed by a neutral point (composed of switch…
The three-phase half-bridge SPWM inverter VSV-PWM state space modulation mapping method is also called the six-step PWM mapping method. It is a drawing method that makes the magnetic flux trajectory tend to be circular, or a method of finding the magnetic flux trajectory using the drawing method. The basic idea is to use numerical control…
The voltage space phasor representation is a method that directly combines the SPWM and the circular trajectory of the motor flux linkage, which was proposed by J.Holtz in 1983. According to the principles of electrical engineering, the sine quantity can be represented by a complex number, that is, it can be represented by the projection…
There are two output forms of three-phase inverter: one is three-phase three-wire output; the other is three-phase four-wire output. Ordinary inverters are three-phase three-wire output, that is, only line voltage can be output. In order to obtain the phase voltage output, that is, to convert the ordinary three-phase inverter into a three-phase four-wire system output,…
There are two control methods for the three-phase half-bridge SPWM inverter: one is to use the complementary switches of the same bridge arm to perform SPWM control according to the waveforms of the phase voltages uA, uB, and uC. This control method is derived from the early inverter control method using the half-controlled switching device…
A circuit form of a three-phase four-wire inverter is shown in Figure 1. This is a four-wire output inverter that uses the midpoint of the DC input supply voltage as the neutral point. For a balanced linear load, the neutral current is equal to zero; but for unbalanced and nonlinear loads, there is a zero-sequence…
The three-phase three-wire inverter circuit using the output filter is shown in Figure 1. When the SPWM control method is adopted, the Fourier series expansion of 3 symmetric switching functions (interface signals) is Using SPWM control, when n=3,5,7,11,13, An=0 can be set, then the inverter output line voltage is In the formula, Ud is the…