Half-period control method of single-phase diode-clamped five-level half-bridge inverter

A technology of half-bridge inverter and control method, which is applied in the direction of converting irreversible DC power input into AC power output, so as to achieve the effect of conveniently designing an output low-pass filter

CN101860244BInactive Publication Date: 2012-04-25NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2012-04-25
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a control method of a single-phase diode-clamped five-level half-bridge inverter. The single-phase diode-clamped five-level half-bridge inverter comprises a power supply circuit (1), a half-bridge arm with a clamping diode, a filter circuit (2) and an output circuit (3) which are sequentially connected, and a half-bridge output five-level voltage supplies power for a load R after being filtered by output filters L and C. The control method has the basic thought that when the current is larger than zero, only switching tubes S1, S2, S3 and S4 of an upper bridge arm are controlled to supply half-period shut-off signals for a lower bridge arm, and when the current is smaller than zero, only switching tubes S5, S6, S7 and S8 of the upper bridge arm are controlled to supply the half-period shut-off signals for the upper bridge arm. The half-period PWM (Pulse Width Modulation) control method solves the dead-zone effect problem brought by adding a dead zone in the PWMcontrol of a five-level bridge type converter.
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Description

technical field

[0001] The invention relates to the technical field of control of a single-phase diode-clamped five-level half-bridge inverter. Background technique

[0002] With the development of society, the application of high-voltage and large-capacity inverters is becoming more and more extensive, and with the continuous improvement of input voltage levels, the limitations of the traditional two-level are becoming more and more obvious, first of all, it is limited by the withstand voltage of power electronic devices , In addition, EMI is large, and the harmonic content of the output voltage is large. In order to solve this problem, multilevel inverters have emerged, among which diode-clamped multilevel inverters are widely used because of their simple control and topology. There are also various control methods, but when these control methods are applied to bridge circuits, they all need to add a dead zone. The addition of the dead zone makes the output voltage of the...

Examples

Embodiment Construction

[0019] Such as figure 2 As shown, the half-bridge arm output voltage V A And the output voltage v obtained by filtering o Waveform, where the bridge arm outputs five levels: "+2U d ","+U d ", "0", "-U d " and "-2U d "(with the cathode of the second DC voltage source as the reference point). When the output voltage v o >0, the output level of the half-bridge arm is "0", "+U d "Switch between" (area a) or level "+U d ","+2U d "Switch between" (area b); when the output voltage v o d Switch between "(c area) or level"-U d ","-2U d " to switch between (zone d).

[0020] Output "+2U d " level, i L >0, such as image 3 (f), all power switches of the upper half-bridge arm are turned on, that is, S 1 , S 2 , S 3 and S 4 At the same time conduction, the current from U d1 Anode outflow, through S 1 , S 2 , S 3 , S 4 , the output filter inductor and filter capacitor flow into U d2 cathode; i L Figure 4 (c), all power switches are turned off, and the current flow...