CN108696218B - Parallel operation control method for direct-current power generation system of double-winding induction generator - Google Patents

Abstract

The invention discloses a parallel operation control method of a DC power generation system of a double-winding induction generator, belonging to the technical field of power generation, transformation or distribution, and in particular to a parallel control method of an independent power supply system of a ship. The method controls the main generator to output DC power stably according to the given value of DC voltage, updates the no-load voltage of the slave generator according to the given value of DC voltage and the output required by the slave generator, and updates the value of the no-load voltage of the slave generator and the power generated by the slave generator. The actual output active power of the generator is updated by the amount deviated from the DC voltage given value from the actual output of the generator. According to the amount of deviation from the DC voltage given value from the generator, the stable output of DC power from the generator and the stable output of the DC voltage given by the two generators are controlled. Parallel operation can be performed when the value is set, which can not only give full play to the advantages of the double-winding induction motor in the independent power supply system, reduce the difficulty of parallel control without increasing the size of the generator in actual operation, and can adapt to the double-winding induction generator in the fields of aerospace and ships. of parallel operation.

Description

Parallel operation control method of double-winding induction generator DC power generation system

technical field

The invention discloses a parallel operation control method of a DC power generation system of a double-winding induction generator, belonging to the technical field of power generation, transformation or distribution, and in particular to a parallel control method of an independent power supply system of a ship.

Background technique

In recent years, the rapid development of multi-electric aircraft, multi-electric ships, and electric vehicles has put forward new requirements for independent power systems such as large capacity, high performance, high power density, and high efficiency. Throughout the development history of power supply systems in aircraft, ships, automobiles and other fields, they all use DC power generation systems, and DC power generation systems are more and more widely used in independent power supply systems. The traditional induction generator system has shortcomings and deficiencies such as the poor quality of the power supply due to the direct connection between the load and the power converter, and the fact that both the active and reactive power of the motor windings pass through the power converter, resulting in an excessively large converter capacity. The system has become an important feasible solution in the field of independent power supply because it can overcome the shortcomings of the traditional induction generator system.

The parallel operation of generators can improve the reliability of power supply. The failure of one generator will not cause the power supply of the entire system to fail. Parallel operation can increase the total output power without the need to increase the DC voltage, which is easy to control.

The existing parallel method is not suitable for the double-winding generator DC power generation system. The existing parallel technology requires two or more generators to perform parallel operation when the voltages and phases are the same, the frequency is the same, the voltage waveform is the same, and the phase sequence is the same, which increases the difficulty of the parallel operation control of the generators, and also increases the actual operation. The volume of the generator is not suitable for the requirements of the aerospace, ship and other fields suitable for the double-winding induction generator. Therefore, it is necessary to research and invent a new control method suitable for the parallel operation of the double-winding induction generator DC power generation system.

SUMMARY OF THE INVENTION

The purpose of the invention of the present invention is to solve the shortcomings of the above-mentioned background technology, to provide a parallel operation control method of a double-winding induction generator DC power generation system, to realize the parallel operation of two double-winding induction generators, and to solve the problems caused by the existing parallel technology. The control is difficult, and the actual operation increases the volume and other technical problems.

The present invention adopts following technical scheme for realizing above-mentioned purpose of invention:

The double-winding induction generator DC power generation system includes a double-winding induction generator as the main generator, a double-winding induction generator as a slave generator, two double-winding induction generators with rated voltage U _dc and DC power generation control The strategies are all the same. The parallel operation control method of the double-winding induction generator DC power generation system provided by the present invention controls the DC output of the two double-winding induction generators based on the droop control principle. Parallel operation is performed when the DC voltage is given.

Droop control of the main generator: According to the droop curve of the main generator, the product of the power P ₁ corresponding to the required output DC voltage U _pDC1 ^* and the droop coefficient K is calculated, the rated voltage U _dc of the main generator minus the power P ₁ and The product of the droop coefficient K obtains the DC voltage given value U _pDC1 ^* , the difference between the DC voltage given value U _pDC1 ^* and the DC bus voltage U _pDC1 of the main generator is adjusted by PI to obtain the given value of the d -axis current of the main generator control winding The value I _cdc1 ^* .

Droop control of the slave generator: Calculate the DC voltage given value U _pDC1 ^* according to the droop curve of the slave generator and add the product of the output target power P2 required from the generator and the droop coefficient K to get the new no _- load voltage from the generator U _pDC2 ^* , from the new no-load voltage U _pDC2 of the generator ^* after subtracting the product of the actual output power P _2m from the generator and the droop coefficient K, subtract the DC bus voltage U _pDC2 from the generator to get the deviation from the actual output DC voltage of the generator to A given value of the d -axis current from the generator control winding I _cdc2 ^* is obtained by performing PI adjustment on the amount deviating from the given value of the DC voltage from the actual output of the generator.

When the output voltages U _pDC1 and U _pDC2 of the main generator and the slave generators are stable, at this time, the output voltages of the two generators are the same and both are given DC voltages, and the DC output terminals of the slave generators are connected in parallel to the DC output of the main generator On the terminal bus, the parallel operation is completed. Two generators running in parallel can distribute power according to the command to realize parallel operation control.

The present invention adopts the above-mentioned technical scheme, and has the following beneficial effects:

(1) The present invention proposes a new parallel operation control method for the DC power generation system of the double-winding induction generator. The main generator is controlled to output DC power stably according to the given value of the DC voltage, and the given value of the DC voltage is used to output the required output from the generator. The active power is updated from the value of the generator no-load voltage, by the updated value from the generator no-load voltage and the active power update from the generator actual output The amount by which the actual output from the generator deviates from the DC voltage given value, according to the deviation from the DC voltage from the generator The quantity control of the given value is to output the DC power from the generator stably and perform parallel operation when the two generators output the given value of the DC voltage stably. The traditional parallel method has many defects in parallel conditions. It reduces the difficulty of parallel control and does not need to increase the size of the generator in actual operation. It can adapt to the parallel operation of dual-winding induction generators in aerospace, marine and other fields.

(2) The present invention adopts the droop characteristic curve to realize parallel operation control, can realize the accurate distribution of the output power of each generator, and improve the reliability and stability of the system.

Description of drawings

FIG. 1 is a schematic diagram of a DC power generation system of two double-winding induction generators operating in parallel.

FIG. 2 is a schematic diagram of the control strategy of a single dual-winding induction generator DC power generation system.

Figure 3 is a schematic diagram of the droop characteristic curves of the master and slave generators.

Detailed ways

The technical solutions of the invention will be described in detail below with reference to the accompanying drawings.

The DC power generation system of two double-winding induction generators running in parallel is shown in Figure 1. One double-winding induction generator is used as the main generator and is connected with the main generator droop controller, and the other double-winding induction motor is used as the slave generator. The generator is connected to the droop controller of the slave generator. When the stable output DC voltage of the two generators is the same, the DC output terminal of the slave generator is connected in parallel to the DC output terminal bus of the main generator, and the two parallel generators are connected to DC load.

The control strategy of the DC power generation system of a single double-winding induction generator is shown in Figure 2. Both generators adopt the same control strategy of controlling the orientation of the flux linkage of the windings. The specific implementation process of the control strategy is as follows: the actual values of the DC voltage output by the generator and the SEC DC bus voltage are compared with their respective reference voltages respectively, and the difference between them is obtained through the proportional integral regulator to obtain the control windings d -axis and q -axis respectively. Then, according to the coordinate transformation formula and the orientation angle, the given value of the three-phase current of the control winding is calculated, and then the control signal of the power switch tube that drives the SEC is obtained. The rated voltage U _dc of each generator is the same.

As shown in Figure 3, in the droop curve of the main generator, it is assumed that the main generator is required to output a DC voltage U _pDC1 ^* , corresponding to point A in the figure, and the power is P ₁ at this time, and the product of the power P ₁ and the droop coefficient K is calculated. .

As shown in Figure 1, at this time, the rated voltage U _dc of the main generator is subtracted from the product of the power P ₁ and the droop coefficient K to obtain the DC voltage given value U _pDC1 ^* , the DC voltage given value U _pDC1 ^* and the main generator DC The difference of the bus voltage U _pDC1 is adjusted by PI to obtain the given value I _cdc1 ^* of the d -axis current of the control winding of the main generator, and the main generator SEC is driven by turning off the control switch, and the given value of the DC voltage U _pDC1 ^* is output when it is stable .

As shown in Figure 3, in the droop curve of the slave generator, it is assumed that the target power P ₂ is required to be output from the generator. If it is to be connected in parallel to the DC bus of the main generator, the slave generator must also output a stable DC voltage given value U. _pDC1 ^* (corresponds to point B in the droop curve from the generator). At this time, the DC voltage given value U _pDC1 ^* is added to the product of the target power P ₂ required from the generator output and the droop coefficient K to obtain the new no-load voltage U _pDC2 ^* from the generator.

As shown in Figure 1, subtract the product of the actual output power P _2m from the generator and the droop coefficient K from the new no-load voltage U _pDC2 ^* of the generator, and then subtract the DC bus voltage U _pDC2 from the generator to obtain the actual output from the generator. The amount deviating from the set value of the DC voltage is adjusted by PI for the amount deviating from the set value of the DC voltage from the actual output of the generator to obtain the set value I _cdc2 ^* of the d -axis current from the control winding of the generator, by controlling the turn-off of the switch tube The drive slave generator SEC, when stable, outputs the DC voltage given value U _pDC1 ^* .

When the main generator and the slave generator output a stable DC voltage given value U _pDC1 ^* at the same time, the DC output terminal of the slave generator is connected in parallel to the DC bus of the DC output terminal of the main generator. The two generators running in parallel can perform power distribution according to the command to realize parallel operation control. This control method is also applicable to the parallel operation of multiple double-winding induction generator DC power generation systems.

Claims (4)

1. A parallel operation control method for a double-winding induction generator DC power generation system is characterized in that one double-winding induction generator is used as a main generator, the other double-winding induction generators are used as auxiliary generators,

regulating d-axis current of a control winding of the main generator by adopting a droop control method according to a given value of direct current voltage, and carrying out SVPWM (space vector pulse width modulation) on the main generator according to the direct current voltage input by the control winding side of the main generator;

updating the idle load voltage of the slave generator according to the voltage corresponding to the target power required to be output from the generator droop curve and the given value of the direct current voltage, obtaining the amount of deviation from the actual output of the generator to the given value of the direct current voltage according to the difference between the updated value of the idle load voltage of the slave generator, the product of the actual output power of the slave generator and the droop coefficient and the actual output direct current voltage of the slave generator, carrying out PI regulation on the amount of deviation from the actual output of the generator to the given value of the direct current voltage to obtain d-axis current of a slave generator control winding, and carrying out SVPWM modulation on the slave generator according to the direct current voltage input from the side of the slave generator;

when the main generator and the slave generator stably output given direct-current voltage, the direct-current output end of the slave generator is connected to a direct-current bus of the direct-current output end of the main generator in parallel.

2. The parallel operation control method of the direct current power generation systems of the double-winding induction generators of claim 1, wherein the method for adjusting the d-axis current of the control winding of the main generator by adopting a droop control method according to the given value of the direct current voltage comprises the following steps: and determining a direct-current voltage given value according to the power corresponding to the direct-current voltage given value on the droop curve of the main generator and the rated voltage of the main generator, and carrying out PI regulation on the direct-current voltage given value and the difference value of the actual output of the main generator to update the d-axis current of the control winding of the main generator.

3. The parallel operation control method of the direct current power generation system of the double-winding induction generator as claimed in claim 1, wherein the droop coefficient K of the master/slave generator is: k ═ Δ U_max/ΔP_maxWherein, Δ U_maxIs the difference between the rated voltage of the master/slave generator and the corresponding voltage at the time of outputting the maximum power, delta P_maxThe maximum power output by the main/auxiliary generator.

4. The parallel operation control method of the direct current power generation system of the double-winding induction generator as claimed in claim 1, wherein the given values of the three-phase currents of the control windings of the master/slave generator are determined according to a coordinate transformation formula and an orientation angle in the process of performing SVPWM modulation on the master/slave generator.

Images