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A pulse width modulation control method and device

A technology of pulse width modulation and pulse width, applied in the field of control, can solve problems such as easy fluctuation, deviation from expected value, damage to switch tube, etc.

Inactive Publication Date: 2016-10-05
SHENZHEN POLYTECHNIC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this method has the following disadvantages: the capacitor voltage V C vs. peak bus voltage V DC is not a linear relationship, although it can control the capacitor voltage V C remains constant, but V DC It will change with the change of the direct duty cycle, the peak value of the bus voltage V DC It is easy to fluctuate or deviate from the expected value, and the bus voltage peak value V DC It may damage the switch tube when it is too high

Method used

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  • A pulse width modulation control method and device
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  • A pulse width modulation control method and device

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Embodiment approach

[0081] As a possible implementation, the method also includes:

[0082] S105: Sampling the DC bus voltage at the action moment of the non-through zero state to obtain the DC bus peak voltage.

[0083] Since the through state ST and the non-through zero state are respectively located at the apex and valley positions of the carrier, that is, the through state ST and the non-through zero state are separated by an effective state, and the through state only appears once in a switching cycle, see Figure 4 , Figure 4 It is a schematic diagram of a state vector provided by an embodiment of the present invention. It can be seen from the figure that the switching state change sequence in the switching period Ts is: V 0 (000), V 4 (100), V 6 (110), straight-through state ST, V 6 (110), V 4 (100), V 0(000). Since the through-duty cycle in practical applications is limited (generally less than 30%, that is, the action time of the through-state ST is relatively short), therefore,...

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Abstract

The invention discloses a pulse width modulation control method. The pulse width modulation control method includes: acquiring a pulse width of a three-phase switch in a switching period; acquiring a first action time of a shoot-through state ST in the switching period; acquiring a second action time of a non-shoot-through null state in the switching period according to the pulse width and the first action time; synthesizing a three-phase pulse width modulation signal according to the switching period, the pulse width, the first action time and the second action time, wherein the shoot-through state ST and the non-shoot-through null state are at positions of a crest and a trough of a carrier wave respectively. Correspondingly, the invention further discloses a PWM (pulse width modulation) control device. Using the pulse width modulation control method and the pulse width modulation control device can directly measure crest voltage on a direct-current busbar to further control busbar voltage directly.

Description

technical field [0001] The invention relates to the field of control technology, in particular to a pulse width modulation control method and device. Background technique [0002] Inverter (Inverter) is a device or device that converts DC power (battery, storage battery) into AC power (generally 220V, 50Hz sine wave), including voltage source inverters, current source inverters and Z sources. Inverter (Z-source inverter, referred to as ZSI). Usually, the control method of the inverter adopts the pulse width modulation (Pulse Width Modulation, PWM) control method. In the traditional PWM control method, the state of the switch tube includes 8 non-through states, of which 6 effective states V1 (001 ), V2(010), V3(011), V4(100), V5(101), V6(110) and 2 zero states V0(000), V7(111), 1 means on, 0 means off . In the voltage source inverter and the current source inverter, the state of the three switching tubes of the lower bridge arm is opposite to that of the three switching tu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/5395
Inventor 钟宇明徐殿国文励洪常江吴志敏
Owner SHENZHEN POLYTECHNIC