Voltage stabilizing method and device for single phase DC-to-AC converter

Abstract

The invention discloses a single-phase inverter stabilizer control method and a device thereof; wherein, the method comprises the steps as follows: the practical output voltage modulus of the inverter is gained; the error of the practical voltage modulus is gained according to the given output voltage modulus and the practical output voltage modulus; the error is adjusted by integral and by multiplying a cosine value with the given phase so as to gain a first adjusting quantity; according to the first adjusting quantity, the output voltage of the inverter is adjusted; the device comprises a practical output voltage modulus gaining unit, a subtracter, an adjuster and a multiplier; the practical output voltage modulus gaining unit gains the practical voltage modulus and outputs the practical voltage modulus to the subtracter, which gains the error according to the given voltage modulus and the practical voltage modulus and outputs the error to the adjuster, which carries out integral adjustment on the error and outputs the value to the multiplier, which multiplies the value output by the adjuster with the cosine value with the given phase so as to gain the first adjusting quantity and outputs the first adjusting quantity to the inverter. The invention has the advantages of high stabilizer precision and quick dynamic response speed.

Description

technical field [0001] The invention relates to a single-phase inverter voltage stabilization control method, and the invention also relates to a single-phase inverter voltage stabilization control device. Background technique [0002] For a three-phase inverter whose output AC voltage differs by 120 degrees, vector control is usually used to convert the three-phase voltage into a vector with a fixed vector length and rotate at a certain speed for control and adjustment. That is, the three-phase A / B / C voltage is transformed into the d / q / 0 coordinate system through coordinate transformation, so that the given three-phase AC voltage becomes the given d / q / 0 three DCs. Under d / q / 0 coordinates, three DC given errors can be adjusted. Since the DC given error is adjusted, the static error can be eliminated in theory, so that the voltage regulation accuracy control of the output voltage of the three-phase inverter becomes relatively easy. But for single-phase inverters, the above-...

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Problems solved by technology

[0004] The disadvantage of existing single-phase inverters is that the instantaneous value of the voltage is given by v ref From constant flow voltage modulo given V mod and AC sine wave cos(ωt+ ) product

However, the disadvantage of this method is that if the effective value is obtained through a hardware circuit, a large filter must be added. If it is calculated by software, the general method can only calculate the effective value once every interval of a power frequency cycle, that is, It is said that the effective value can be adjusted once every interval of a power frequency cycle, so that the adjustment cycle of the effective value adjustment will be longer, and the response to similar load changes such as sudden increase and sudden unloading will be slower

This will affect the dynamic response speed of the voltage control loop, voltage regulation speed, etc.

Even if the effective value is calculated in real time by software (which will take up more storage resources and code execution time), the calculated effective value can only reflect the magnitude of the voltage in one cycle before each calculation time, and for a certain time load The sudden change in voltage caused by the sudden change, due to the periodicity of the effective value calculation, the sudden change in voltage will be integrated by the stable voltage at other times in the whole cycle, and it is difficult to show the real-time change of the voltage, thus affecting the adjustment effect

The hardware method generally adopts the method of rectifying and filtering the AC voltage after sampling to obtain the feedback value that is actually the average value of the voltage, and then adjusts the voltage. Since a low-pass filter with a large time constant is required, the lag time will be longer

In summary, the use of effective value for non-difference adjustment determines that the adjustment has relatively poor real-time performance, and the adjustment delay is relatively large, which affects the dynamic response of the adjustment and leads to poor dynamic performance of the inverter.

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