CN103346586B - The method for handover control of double-mode converter in a kind of three-phase microgrid - Google Patents

Abstract

The method for handover control of double-mode converter in a kind of three-phase microgrid.When current transformer by group net operation be switched to be incorporated into the power networks time, by the tuning controller unit adjustment output voltage amplitude of current transformer and frequency, after meeting grid-connected requirement, closed by static switch, current transformer is converted to Current Control, enters the pattern of being incorporated into the power networks; When electric network state exception being detected or needing to switch to autonomous operational mode, by the given value of current value of tuning controller unit adjustment current transformer, static switch is disconnected simultaneously, then current transformer is converted to voltage control, enters group net operation pattern.The present invention controls simply, can improve stability and the reliability of double-mode converter.

Description

The method for handover control of double-mode converter in a kind of three-phase microgrid

Technical field

The present invention relates to the method for handover control of double-mode converter in a kind of micro-capacitance sensor.

Background technology

Micro-capacitance sensor, except grid-connected and networking two kinds of steady state mode of operation, also also exists the transient process changed between two kinds of patterns.The mode of patten transformation is not restarting of power supply, but while current transformer constantly works, ensure the continuous and stable transition of netting interior voltage by the adjustment of its aspect such as control method and network configuration, namely realize taking over seamlessly, unaffected to guarantee the power supply of local load.At present, existing current transformer just adopts simple Current Control or voltage control mostly, realizes being incorporated into the power networks or group net operation, and power is little, inhibits the development of micro-capacitance sensor.

Summary of the invention

For overcoming the shortcoming of prior art, the present invention proposes a kind of method for handover control to the double-mode converter in three-phase microgrid.The invention enables current transformer both can be incorporated into the power networks also can group net operation.The present invention is also applicable to high-power ruuning situation.

The method for handover control of double-mode converter of the present invention realizes being incorporated into the power networks taking over seamlessly between pattern and group net operation pattern by tuning controller unit.

The present invention adopts following technical scheme for achieving the above object:

Double-mode converter system in described three-phase microgrid comprises double-mode converter, sample circuit, grid-connected cell controller, networking cell controller and cooperation control unit.

Described double-mode converter comprises DC bus power supply Vdc, three phase inverter bridge, three-phase filter inductance, three-phase filter capacitor and three-phase transformer.

Control method of the present invention is realized by net-connected controller unit, networking controller unit and the cooperation control unit be integrated in a dsp controller.

The voltage that sample circuit will gather, current signal is sent to net-connected controller unit, networking controller unit and tuning controller unit by holding wire.Double-mode converter, connected by busbar between local load and electrical network, net-connected controller unit, networking controller unit and tuning controller unit are with double-mode converter, be connected by serial communication between load and electrical network.

In three-phase microgrid of the present invention the method for handover control of double-mode converter be double-mode converter be in be incorporated into the power networks pattern time, grid-connected current is controlled by the electric current of net-connected controller unit controls filter inductance, when double-mode converter is in group net operation pattern, by networking controller unit controls current transformer load voltage; When double-mode converter is in the process of the pattern of being incorporated into the power networks and group net operation patten transformation, realize being incorporated into the power networks taking over seamlessly between pattern and group net operation pattern by cooperation control unit.

In described net-connected controller unit, control grid-connected current mainly through the electric current controlling filter inductance, realize grid-connected requirement.In the process of being incorporated into the power networks, the line voltage collected and filtered current signal are sent to dsp chip by sample circuit, produce pwm signal, through drive circuit Direct driver three phase inverter bridge through net-connected controller unit.

In described networking cell controller, mainly through controlling load voltage and the filter inductance electric current of current transformer, carry out the power supply quality of guaranteed load.When group net operation, the current transformer load voltage collected and filtered current signal are sent to dsp chip by sample circuit, produce pwm signal through networking controller unit, export, Direct driver three phase inverter bridge through drive circuit.

Current transformer by group net operation patten transformation for be incorporated into the power networks pattern time, tuning controller unit detects amplitude and the frequency that the amplitude of the line voltage obtained and frequency constantly adjust double-mode converter load voltage by sample circuit, the knots modification of given amplitude and frequency is determined according to difference in magnitude and frequency extent, thus change amplitude and the frequency of double-mode converter output voltage, realize taking over seamlessly of double-mode converter.

Tuning controller unit current transformer by group net operation patten transformation for be incorporated into the power networks pattern time, detected the amplitude U of the line voltage obtained in real time by sample circuit _gand frequency f _gconstantly adjust the amplitude U (k-1) of the given voltage of double-mode converter ^*with frequency f (k-1) ^*, according to difference in magnitude Δ U(U _g-U (k-1) ^*) and difference on the frequency Δ f(f _g-f (k-1) ^*) size, determine given voltage magnitude U (k-1) ^*with frequency f (k-1) ^*knots modification, by adjustment after current transformer voltage magnitude U (k) ^*with frequency f (k) ^*as the set-point of bimodulus current transformer, thus change amplitude and the frequency of current transformer load voltage, networking controller cell voltage amplitude U (k) after adjustment ^*with frequency f (k) ^*value be shown below:

$\left\{\begin{array}{c}f{\left(k\right)}^{*}=\frac{f_g-f{(k-1)}^{*}}{n}+f{(k-1)}^{*}=\frac{\mathrm{\Δf}}{n}+f{(k-1)}^{*}\\ U{\left(k\right)}^{*}=\frac{U_g-U{(k-1)}^{*}}{n}+U{(k-1)}^{*}=\frac{\mathrm{\ΔU}}{n}+U{(k-1)}^{*}\end{array}\right.$

In formula: n represents integer, k represents the k moment, and (k-1) represents (k-1) moment, f (k) ^*represent the given electric voltage frequency in k moment, f (k-1) ^*represent the given electric voltage frequency in (k-1) moment, U (k) ^*represent the given voltage magnitude in k moment, U (k-1) ^*represent the given voltage magnitude in (k-1) moment.

After meeting grid-connected requirement, by voltage magnitude U (k) obtained after adjustment ^*with frequency f (k) ^*as the set-point of bimodulus current transformer, ensure that current transformer load voltage and electric current are not undergone mutation with this, realize taking over seamlessly.After current transformer stable operation, be Current Control by net-connected controller cell translation, realize being incorporated into the power networks.

When grid collapses or initiative current transformer are converted to group net operation by being incorporated into the power networks, tuning controller unit adjusts rapidly the given current i of current transformer _d ^*, i _q ^*, work as i _d ^*, i _q ^*after matching with load current, current transformer being converted to group net operation, after current transformer stable operation, is voltage control by networking controller cell translation, ensures the output of current transformer, realizes taking over seamlessly.

The present invention can make double-mode converter realize taking over seamlessly in group net operation and the mutual transient process switched that is incorporated into the power networks, and can improve stability and the reliability of electric power system.

Accompanying drawing explanation

Fig. 1 double-mode converter system architecture diagram;

Fig. 2 double-mode converter structure chart.

Embodiment

The present invention is further illustrated below in conjunction with the drawings and the specific embodiments.

As shown in Figure 1, double-mode converter system comprises double-mode converter 1, grid-connected cell controller 3, networking cell controller 2, cooperation control unit 4, sample circuit 5.

As shown in Figure 2, double-mode converter 1 comprises DC bus power supply Vdc, three phase inverter bridge 101, three-phase filter inductance 102, three-phase filter capacitor 103 and three-phase transformer 104, current transformer is that load 105 is powered, by static switch 106 to electrical network conveying capacity in addition.

The voltage that sample circuit 5 will gather, current signal is sent to net-connected controller unit, networking controller unit and tuning controller unit by holding wire.Double-mode converter, connected by busbar between load and electrical network, cutting-in control unit, networking control unit and cooperation control unit are with double-mode converter, be connected by serial communication between load and electrical network.

In three-phase microgrid of the present invention, the control method of double-mode converter is as follows:

In described net-connected controller unit, control grid-connected current mainly through the electric current controlling filter inductance, realize grid-connected requirement.In the process of being incorporated into the power networks, the line voltage collected and filtered current signal are sent to dsp chip by sample circuit, produce pwm signal, through drive circuit Direct driver three phase inverter bridge through net-connected controller unit.

In described networking cell controller, mainly through controlling load voltage and the filter inductance electric current of current transformer, carry out the power supply quality of guaranteed load.When group net operation, the current transformer load voltage collected and filtered current signal are sent to dsp chip by sample circuit, produce pwm signal, through drive circuit Direct driver three phase inverter bridge through networking controller unit.

Described tuning controller unit detects amplitude and the frequency of the line voltage obtained in real time by sample circuit, the output voltage amplitude of continuous adjustment current transformer and frequency, according to difference in magnitude and frequency extent, determine the knots modification of given amplitude and frequency, thus change amplitude and the frequency of current transformer load voltage, realize taking over seamlessly of double-mode converter.

Tuning controller unit current transformer by group net operation be converted to be incorporated into the power networks time, the given voltage of current transformer and frequency are respectively U (k-1) ^*with f (k-1) ^*, by the amplitude U of the real-time detection of grid voltage of sample circuit 5 _gand frequency f _gconstantly adjust U (k) ^*with f (k) ^*, according to difference in magnitude Δ U(U _g-U (k-1) ^*) and difference on the frequency Δ f(f _g-f (k-1) ^*) size, determine given amplitude U (k-1) ^*with frequency f (k-1) ^*knots modification, by adjustment after current transformer voltage magnitude U (k) ^*with frequency f (k) ^*as the set-point of bimodulus current transformer, change amplitude and the frequency of current transformer output voltage, thus change amplitude and the frequency of current transformer load voltage, networking controller cell voltage amplitude U (k) after adjustment ^*with frequency f (k) ^*value be shown below:

$\left\{\begin{array}{c}f{\left(k\right)}^{*}=\frac{f_g-f{(k-1)}^{*}}{n}+f{(k-1)}^{*}=\frac{\mathrm{\Δf}}{n}+f{(k-1)}^{*}\\ U{\left(k\right)}^{*}=\frac{U_g-U{(k-1)}^{*}}{n}+U{(k-1)}^{*}=\frac{\mathrm{\ΔU}}{n}+U{(k-1)}^{*}\end{array}\right.$

N represents integer, and k represents the k moment, and (k-1) represents (k-1) moment, f (k) ^*represent the given frequency in k moment, f (k-1) ^*represent the given frequency in (k-1) moment, U (k) ^*represent the given voltage magnitude in k moment, U (k-1) ^*represent the given voltage magnitude in (k-1) moment.

After meeting grid-connected requirement, by voltage magnitude U (k) obtained after adjustment ^*with frequency f (k) ^*as the set-point of current transformer, realize taking over seamlessly.After current transformer stable operation, be changed to Current Control by net-connected controller unit, realize being incorporated into the power networks.

When grid collapses or initiative current transformer are converted to group net operation by being incorporated into the power networks, tuning controller unit adjusts rapidly the given current i of current transformer _d ^*, i _q ^*, work as i _d ^*, i _q ^*after matching with load current, current transformer is converted to group net operation, after current transformer stable operation, is changed to voltage control by networking controller unit, ensure the output of current transformer, realize taking over seamlessly.

Claims (2)

1. the method for handover control of double-mode converter in a three-phase microgrid, in described three-phase microgrid, the method for handover control of double-mode converter is, double-mode converter be in be incorporated into the power networks pattern time, control grid-connected current by the electric current of net-connected controller unit controls filter inductance; When double-mode converter is in group net operation pattern, by networking controller unit controls current transformer load voltage; When double-mode converter is in the process of the pattern of being incorporated into the power networks and group net operation patten transformation, realize being incorporated into the power networks taking over seamlessly between pattern and group net operation pattern by tuning controller unit,

It is characterized in that: described double-mode converter by group net operation patten transformation for be incorporated into the power networks pattern time, described tuning controller unit adjustment detects the amplitude U of the line voltage obtained in real time by sample circuit _gand frequency f _gconstantly adjust the amplitude U (k-1) of the given voltage of double-mode converter ^*with frequency f (k-1) ^*, k represents the k moment, and (k-1) represents (k-1) moment, according to difference in magnitude △ U (U _g-U (k-1) ^*) and difference on the frequency △ f (f _g-f (k-1) ^*) size, determine given voltage magnitude U (k-1) ^*with frequency f (k-1) ^*knots modification, by adjustment after current transformer voltage magnitude U (k) ^*with frequency f (k) ^*as the set-point of double-mode converter, change amplitude and the frequency of double-mode converter load voltage, realize taking over seamlessly; After double-mode converter stable operation, be Current Control by net-connected controller cell translation, realize being incorporated into the power networks;

Current transformer voltage magnitude U (k) after described adjustment ^*with frequency f (k) ^*value be shown below:

$\left\{\begin{array}{c}f{\left(k\right)}^{*}=\frac{f_g-f{(k-1)}^{*}}{n}+f{(k-1)}^{*}=\frac{\mathrm{\Δf}}{n}+f{(k-1)}^{*}\\ U{\left(k\right)}^{*}=\frac{U_g-U{(k-1)}^{*}}{n}+U{(k-1)}^{*}=\frac{\mathrm{\ΔU}}{n}+U{(k-1)}^{*}\end{array}\right.$

In formula: n represents integer, k represents the k moment, and (k-1) represents (k-1) moment, f (k) ^*represent the given electric voltage frequency in k moment, f (k-1) ^*represent the given electric voltage frequency in (k-1) moment, U (k) ^*represent the given voltage magnitude in k moment, U (k-1) ^*represent the given voltage magnitude in (k-1) moment.

2. the method for handover control of double-mode converter in three-phase microgrid according to claim 1, it is characterized in that: when the double-mode converter described in grid collapses or initiative is converted to group net operation by being incorporated into the power networks, described tuning controller unit adjusts rapidly the given current i of current transformer _d ^*, i _q ^*, when given current i _d ^*, i _q ^*after matching with load current, double-mode converter being converted to group net operation, after double-mode converter stable operation, is voltage control by networking controller cell translation.