Unlock instant, AI-driven research and patent intelligence for your innovation.

A three-level inverter pwm pulse sealing method and device

A three-level inverter, inverter technology, applied in emergency protection circuit devices, electrical components and other directions, can solve the problem of switching tube voltage stress exceeding the standard, to solve the midpoint offset, reduce the impact, and solve the voltage stress effect of the problem

Active Publication Date: 2018-10-02
SUNGROW POWER SUPPLY CO LTD
View PDF5 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] In order to solve the problems in the prior art, the present invention provides a PWM pulse sealing method and device for a three-level inverter, which can solve the problem that the voltage stress of the switching tube exceeds the standard after the PWM wave sealing

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • A three-level inverter pwm pulse sealing method and device
  • A three-level inverter pwm pulse sealing method and device
  • A three-level inverter pwm pulse sealing method and device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0102] And the three-level inverter PWM pulse sealing method provided by the present invention is suitable for Figure 1-Figure 3 The topology structures of the T-type and Type 1 three-level inverters shown are also applicable to other variants of the T-type and Type-1 three-level inverters.

[0103] Figure 1-Figure 3 It is only the topology structure of the single-phase inverter. The inverter corresponding to a is used as an example to illustrate the following. The wave sealing method of the inverter corresponding to phase b and c is the same as that of phase a, so it will not be repeated here.

[0104] refer to Figure 4 , which is a flow chart of Embodiment 1 of the PWM pulse wrapping method for a three-level inverter provided by the present invention.

[0105] The inverter includes: a first switching tube Q1, a second switching tube Q2, a third switching tube Q3 and a fourth switching tube Q4;

[0106] Three-level inverter PWM pulse sealing methods include:

[0107] S...

Embodiment 2

[0117] refer to Figure 5 , is a flow chart of Embodiment 2 of the PWM pulse wrapping method for a three-level inverter provided by the present invention.

[0118] S501 and S502 in this embodiment are the same as S401 and S402 in the first method embodiment, and will not be repeated here.

[0119] Also included in this embodiment:

[0120] S503: When the bridge arm current Ia is greater than the first preset current I1 and enters the first preset current interval [I2, I1], control the second switching tube Q2 to turn on, and the third switching tube Q3 to turn off ;

[0121] S504: When the bridge arm current Ia enters the first preset current interval [I2, I1] from less than the second preset current I2, control the third switching tube Q3 to turn on, and the second switching tube Q2 turn off;

[0122] S505: When the bridge arm current Ia is within the first preset current range [I2, I1], keep the off-states of the second switching tube Q2 and the third switching tube Q3 u...

Embodiment 3

[0134] refer to Figure 6 , which is a flow chart of Embodiment 3 of the PWM pulse wrapping method for a three-level inverter provided by the present invention.

[0135] S601 in this embodiment is the same as S401 in Method Embodiment 1, and details are not repeated here.

[0136] S602: Control the second switching transistor Q2 and the third switching transistor Q3 to be turned on alternately for a third predetermined time period t3 with a first preset period Tx, and then complete the wave blocking process.

[0137] It can be understood that the second switching tube Q2 and the third switching tube Q3 are controlled to be turned on alternately in the first preset period Tx, that is, during the period T1, the switching tube Q2 is first controlled to be turned on and the switching tube Q3 is turned off; During the period T2, control the second switching tube Q2 to turn off and the third switching tube Q3 to turn on; during the period T3, control the switching tube Q2 to turn o...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The embodiment of the invention discloses a PWM pulse blocking method and device for a three-level inverter applied to a T-type three-level inverter and an I-type three-level inverter. The inverter comprises a first switch tube, a second switch tube, a third switch tube and a fourth switch tube. The method comprises the following steps: receiving a PWM pulse blocking instruction, controlling the first switch tube and the fourth switch tube to be turned off, and then controlling the second switch tube and the third switch tube to be turned off after a first preset time period; detecting a bridge arm current output by the inverter; and controlling on / off states of the second switch tube and the third switch tube according to the magnitude of the bridge arm current. A low-current zero-level freewheel loop is forcibly built when a freewheel current passes through a zero point, so that the two-level freewheel condition is avoided in the current commutating process; the problem of impact to a semi-bus capacitor caused by a blocking state is reduced; and the problem of voltage stress of each switch tube is effectively solved. According to the method and the device provided by the invention, the implementation scheme is simple and easy; the cost is low; and the safety performance of system grid connection is greatly improved.

Description

technical field [0001] The invention relates to the technical field of inverter control, in particular to a PWM pulse wrapping method and device for a three-level inverter. Background technique [0002] Inverters, also known as DC / AC converters, are used to convert direct current into alternating current, and are widely used in new energy generation fields such as wind power generation and photovoltaic power generation. The application of the inverter is more and more extensive, and its control is more and more important. [0003] see figure 1 , which is a schematic topology diagram of a T-shaped three-level inverter in the prior art. [0004] In the prior art, the conventional method of blocking the PWM of the inverter is: [0005] After the controller sends out the PWM wave sealing command, the PWM pulses driving the first switching tube Q1, the second switching tube Q2, the third switching tube Q3, and the fourth switching tube Q4 are simultaneously blocked, that is, t...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/122
CPCH02H7/122
Inventor 李晓迅杨本和申凯江鹏孟杰
Owner SUNGROW POWER SUPPLY CO LTD