CN-122000185-A - Energy storage type flexible on-load voltage regulating transformer based on power control and model predictive control method thereof

CN122000185ACN 122000185 ACN122000185 ACN 122000185ACN-122000185-A

Abstract

The invention discloses an energy storage type flexible on-load voltage regulating transformer based on power control and a model prediction control method thereof, belonging to the technical field of transformer topology and control, wherein the transformer comprises a multi-winding transformer, a plurality of on-load tap switches, a power electronic converter and an energy storage module; the invention discloses a power control-based primary side winding of an energy storage type flexible on-load voltage regulating transformer, which comprises a main winding, a plurality of sectional windings and an isolation winding, wherein the main winding and the sectional windings are respectively connected with an on-load tap-changer, the on-load tap-changer acts to cut off or connect the primary side winding of the energy storage type flexible on-load voltage regulating transformer, the isolation winding provides energy for a power electronic converter and is connected with an input side of the power electronic converter, the power electronic converter is a back-to-back power electronic converter, and an energy storage module is connected to a direct current side of the power electronic converter, so that the problem of insufficient power quality control capability of the flexible on-load voltage regulating transformer is solved.

Inventors

YIN JINGYUAN
XIAO HAO
SUN LONGFEI
MA SHIQIAN
GUO BOWEN
WANG ZHISHUANG
JIN CUICUI
WEI TONGZHEN

Assignees

中国科学院电工研究所
国网天津市电力公司

Dates

Publication Date: 20260508
Application Date: 20260115

Claims (10)

1. The energy storage type flexible on-load voltage regulating transformer based on power control is characterized by comprising a multi-winding transformer T1, a plurality of on-load tap switches K 0 ~K n , a power electronic converter and an energy storage module; The primary side winding of the energy storage type flexible on-load voltage regulating transformer based on power control comprises a main winding N 1m , a plurality of segmented windings N 11 ~N 1n and an isolation winding N 3 , wherein N represents the number of the segmented windings, the main winding N 1m and the segmented windings N 11 ~N 1n are respectively connected with an on-load tap switch K 0 ~K n , the on-load tap switch K 0 ~K n acts to cut off or connect the primary side winding of the energy storage type flexible on-load voltage regulating transformer, and the isolation winding N 3 provides energy for the power electronic converter and is connected with the input side of the power electronic converter; the power electronic converter is a back-to-back power electronic converter, the output of the power electronic converter is coupled in series to a main circuit of a primary side winding of an energy storage type flexible on-load voltage regulating transformer based on power control through an isolation transformer T 2 , and an energy storage module is connected to the direct current side of the power electronic converter; The power electronic converter is composed of a parallel-side converter and a series-side converter, the parallel-side converter is filtered through a grid-connected inductor L 1 , the series-side converter is filtered through a low-pass filter composed of a filter inductor L 2 and a filter capacitor C 2 , and the output of the power electronic converter is coupled in series through an isolation transformer T 2 to a main circuit of a primary side winding of the energy storage type flexible on-load voltage regulating transformer based on power control.
2. The power control-based energy storage type flexible on-load tap changer of claim 1, wherein the parallel side converter and the series side converter are each single-phase full-bridge circuits.
3. The power control-based energy storage type flexible on-load tap changer of claim 2, wherein the circuit equation of the parallel-side converter and the series-side converter is: (2) Wherein, the In order to be able to take time, 、 Network side voltages of the parallel side converter and the series side converter respectively; For the series side converter to output a voltage, For the output current of the series-side converter, For the input voltage of the parallel side converter, For the input current of the parallel side converter, For the current through the inductance L 2 .
4. The power control-based energy storage type flexible on-load voltage regulating transformer according to claim 3, wherein the relation among the power of the direct current side of the power electronic converter, the active power flowing from the primary side to the secondary side of the multi-winding transformer T1 and the active power of the load side is: (12) Wherein, the For the power on the dc side of the power electronic converter, For the active power output by the energy storage module, As the active power on the load side, As a ratio of the grid voltage dip value to the grid voltage rating, Active power flowing from the primary side to the secondary side of the multi-winding transformer T1.
5. A model predictive control method of an energy storage type flexible on-load voltage regulating transformer based on power control, which is used for the energy storage type flexible on-load voltage regulating transformer based on power control as set forth in any one of claims 1 to 4, and is characterized by comprising the predictive control of a parallel side converter model and the model predictive control of a series side converter; the predictive control of the parallel side converter model includes real-time acquisition of parallel side converter input voltage And input current And will 、 After being converted into alpha-axis and beta-axis components, the real-time active power of the parallel side converter is obtained through instantaneous power calculation And reactive power DC bus voltage reference value The power is calculated by the difference value with the actual value u dc of the DC bus voltage, and then the output of the PI regulator is multiplied with the actual value u dc of the DC bus voltage through a PI regulator, and then added with the SOC feedforward value of the energy storage module to obtain the active reference power P ref of the parallel side converter Then generating a switching signal of the parallel side converter through SPWM control; The model predictive control of the series-side converter includes collecting the series-side converter output voltage u c2 at the first The value of the sampling interval is equal to the first The values of the sampling intervals give u c2 in the first place The values of the sampling intervals are then used to optimize the modulation function using a model predictive instantaneous power control scheme And finally, generating a switching signal of the series-side converter through SPWM control.
6. The model predictive control method for a power control-based energy storage type flexible on-load tap changer of claim 5, wherein in the predictive control of the parallel side converter model, the real-time active power of the parallel side converter is obtained through instantaneous power calculation And reactive power : (14) Wherein, the Input voltage for parallel side converters An axis component of the optical fiber, Input voltage for parallel side converters Axial component For the nominal peak value of the parallel side converter input current, Inputting current to parallel side converters An axis component of the optical fiber, Inputting current to parallel side converters An axis component.
7. The method for model predictive control of a power control based energy storage type flexible on-load tap changer of claim 6 wherein in the predictive control of the parallel side converter model, the parallel side converter is at the first stage Active power of individual sampling intervals And reactive power The method comprises the following steps: (18) After the variable is added Is shown in the first The variable of the sampling interval is added to Is shown in the first This variable of the sampling interval is used for the time interval, wherein, the Is a time variable in the modulation function; Cost function for parallel side converter model predictive control The method comprises the following steps: (19) Wherein, the And Respectively the first Active and reactive reference power of parallel side converters of a sampling interval, In order to sample the time of the sample, In order to be of an angular frequency, For the nominal peak value of the parallel side converter input voltage, For the network-side voltage of parallel-side converters An axis component of the optical fiber, For the network-side voltage of parallel-side converters An axis component.
8. The model predictive control method for a power control-based energy storage type flexible on-load tap changer of claim 7, wherein in the predictive control of the parallel side converter model, the optimized modulation function The method comprises the following steps: (23) Wherein, the Is a direct current side voltage.
9. The model predictive control method for a power control-based energy storage type flexible on-load tap changer of claim 5, wherein in the model predictive control of the series side converter, the series side converter output voltage is collected First, the The value of the sampling interval is equal to the first Substituting the values of the sampling intervals into (28) to obtain In the first place The values of the sampling intervals The modulation function is then optimized by equation (33) using a model predictive instantaneous power control scheme ; (28) Is that In the first place The values of the individual sampling intervals are chosen, Is that In the first place The values of the individual sampling intervals are chosen, In order to sample the time of the sample, The first series-side converter Network side voltages at sampling intervals; cost function for series-side converter model predictive control The definition is as follows: (29) Wherein, the Is the first Reference values of the series-side converter output voltages for the sampling intervals, Is that In the first place The values of the sampling intervals.
10. The model predictive control method for a power control-based energy storage type flexible on-load tap changer of claim 9, wherein in the model predictive control of the series side converter, the optimized modulation function The method comprises the following steps: (33) Wherein, the Is a direct current side voltage.

Description

Energy storage type flexible on-load voltage regulating transformer based on power control and model predictive control method thereof Technical Field The invention belongs to the technical field of transformer topology and control, and particularly relates to an energy storage type flexible on-load voltage regulating transformer based on power control and a model predictive control method thereof. Background In the prior art, after photovoltaic power generation is connected to the direct current side of a power electronic converter, electric energy generated by the photovoltaic power generation must be output in real time through a parallel side converter, a photovoltaic power generation unit must generate power in illumination time, an energy storage unit without buffering is not needed, and power control is limited. The flexible on-load voltage regulating transformer in the prior art can enable the power electronic converter to output compensation voltage with a certain phase angle and amplitude by controlling the output voltage of the power electronic converter, and further realize continuous voltage regulation by coordinated control of the power electronic converter and the on-load tap changer, so that the technical problem that the traditional on-load voltage regulating transformer can only realize discrete voltage regulation is solved. However, to increase the voltage output range of the series-side converter, and even the inductor current range of the parallel-side converter, of the power electronic converter of the flexible on-load tap-changing transformer can only be achieved by increasing the power class of the whole power electronic converter. In view of the difficulty in rapidly calculating and controlling the output voltage of the series-side converter according to various conditions, and the strong power coupling between the parallel-side converter and the series-side converter, the difficulty in directly controlling the parallel-side converter according to the instantaneous power, there is a need to solve the problem of improving the power quality control capability without increasing the input voltage of the power electronic converter. The technical aim of the invention is to realize that the voltage output range of the series-side converter or the inductance current range of the parallel-side converter of the flexible on-load voltage regulating transformer can be expanded without improving the power grade of the whole power electronic converter. Disclosure of Invention In order to solve the technical problems, the invention adopts the following technical scheme: An energy storage type flexible on-load voltage regulating transformer based on power control comprises a multi-winding transformer T1, a plurality of on-load tap-changers K 0~Kn, a power electronic converter and an energy storage module; The primary side winding of the energy storage type flexible on-load voltage regulating transformer based on power control comprises a main winding N 1m, a plurality of segmented windings N 11~N1n and an isolation winding N 3, wherein N represents the number of the segmented windings, the main winding N 1m and the segmented windings N 11~N1n are respectively connected with an on-load tap switch K 0~Kn, the on-load tap switch K 0~Kn acts to cut off or connect the primary side winding of the energy storage type flexible on-load voltage regulating transformer, and the isolation winding N 3 provides energy for the power electronic converter and is connected with the input side of the power electronic converter; the power electronic converter is a back-to-back power electronic converter, the output of the power electronic converter is coupled in series to a main circuit of a primary side winding of an energy storage type flexible on-load voltage regulating transformer based on power control through an isolation transformer T 2, and an energy storage module is connected to the direct current side of the power electronic converter; The power electronic converter is composed of a parallel-side converter and a series-side converter, the parallel-side converter is filtered through a grid-connected inductor L 1, the series-side converter is filtered through a low-pass filter composed of a filter inductor L 2 and a filter capacitor C 2, and the output of the power electronic converter is coupled in series through an isolation transformer T 2 to a main circuit of a primary side winding of the energy storage type flexible on-load voltage regulating transformer based on power control. A model prediction control method of an energy storage type flexible on-load voltage regulating transformer based on power control is used for the energy storage type flexible on-load voltage regulating transformer based on power control and comprises the following steps of prediction control of a parallel side converter model and model prediction control of a series side converter; the predictive control of the parallel side conve