CN202333813U - Multifunctional electric energy quality regulator based on voltage type inverter - Google Patents

Abstract

The utility model discloses a multifunctional power quality regulator based on a voltage type inverter. The regulator is composed of a main circuit and a control circuit; the main circuit is composed of a three-phase rectifier bridge, an inverter power module, an output filter, and an isolation transformer; the control circuit is composed of a sampling circuit, a DSP controller, a photoelectric isolation input Control computer composition. The main circuit consists of three-phase rectifier bridge, inverter power module, output filter and isolation transformer. The beneficial effects of the utility model are: the utility model can greatly improve the running time and efficiency of the reactive power compensation device, reduce the maintenance workload, give full play to the dynamic and fast adjustment function of the device, and strengthen the reactive power and voltage regulation ability of the central point , promote the rapid realization of reactive power balance and voltage stability of the regional power grid, and improve the modernization and automation level of the power grid.

Description

Multifunctional Power Quality Conditioner Based on Voltage Type Inverter

technical field

The utility model relates to a power quality regulator, in particular to a multifunctional power quality regulator based on a voltage type inverter.

Background technique

With the development of power electronics technology, nonlinear power electronic devices and devices have been widely used in modern industry. The operation of these devices makes the voltage and current waveform distortion in the power grid more and more serious, and the harmonic pollution is becoming more and more serious. In addition, impact and fluctuating loads, such as electric arc furnaces, large rolling mills, electric locomotives, etc., will not only generate a large number of high-order harmonics during operation, but also cause voltage fluctuations, drops, three-phase imbalances, power supply interruptions, etc. The problem of power quality is that the alternating current output by the grid is not a stable sine wave, which makes the quality of power supply continue to deteriorate. On the other hand, with the continuous popularization of various complex, sophisticated and power-quality-sensitive electrical equipment, people have higher and higher requirements for power quality, so power quality has become a hot spot in current research.

At present, the main means of improving power quality, such as passive filters, contact switches or thyristor switching capacitors, static var compensation devices, and uninterruptible power supply (UPS), etc., are not the most effective way to solve power quality problems . Can not meet people's higher requirements for power quality. In 1976, L. Gyugyi et al. used a pulse width modulation (PWM) converter based on high-power transistors to form an active power filter (APF) and a static var generator (DSTATCOM) to eliminate grid harmonics and improve voltage quality. , Compensate reactive power, improve load imbalance, etc. Since then, with the rapid development of power electronics technology and PWM technology, and in-depth research on reactive power theory under non-sinusoidal conditions, especially the instantaneous reactive power theory proposed by Japanese scholar H.Akagi et al., APF and DSTATCOM have been obtained Rapid development and improvement. And began to gradually shift from the experimental stage to the industrial application stage. The multifunctional power quality conditioner described in this claim can simultaneously realize functions such as power factor and load voltage regulation, and filtering of grid harmonics.

Utility model content

The purpose of the utility model is to provide a multifunctional power quality regulator based on a voltage type inverter. The power quality conditioner has a simple structure, and can realize functions such as power factor and load voltage regulation as well as filtering grid harmonics at the same time.

The technical scheme that the utility model solves the problems of the technologies described above is:

A multi-functional power quality conditioner based on a voltage-type inverter is composed of a main circuit and a control circuit. The main circuit consists of a three-phase rectifier bridge, an inverter power module, an output filter, and an isolation transformer. The control circuit is composed of sampling circuit, DSP controller, photoelectric isolation input and output circuit and industrial control computer;

1) Structure of each part

The output filter is composed of inductors and capacitors; the DSP controller has three ports I, II, and III, and the I port of the DSP controller is the I/O input and output port; the II port is the sampling module; the III port is the communication module;

2) The connection relationship of each component

One end of the three-phase rectifier bridge is connected to the power grid, and the other end is connected to the inverter power module of the voltage support capacitor C. The output end of the inverter power module is connected to one end of the output filter, and the other end of the output filter is connected to the isolation transformer. The primary side, the secondary side of the isolation transformer is connected to the grid;

The output terminal of the sampling circuit is connected to the II of the DSP controller, the I of the DSP controller is connected to the photoelectric isolation input and output circuit through an optical fiber, and the output terminal of the photoelectric isolation input and output circuit is connected to the inverter power module; the III of the DSP controller is connected to the industrial The control computer is connected through the RS232 serial port;

The above-mentioned inverter power module adopts the FF450R17ME3 module of infineon (Infineon).

The turns ratio of the primary and secondary sides of the above isolation transformer is 1:2.

The DSP controller module mentioned above adopts the DPS2812M controller of Hezhongda Company.

The above-mentioned sampling circuit uses two AD7656 chips with a precision of 16 bits.

The beneficial effects of the utility model are:

1) In terms of improving the transient stability of the system and damping system oscillation, the performance of the multifunctional power quality conditioner is much better than that of the traditional synchronous condenser;

2) Using digital control technology, the system has high reliability and basically does not require maintenance, which can save a lot of maintenance costs; at the same time, the optimal control of reactive power flow and voltage can be realized through the EMS of the dispatching center. It is a digital power system (DPS) under construction Part;

3) The control is flexible and the adjustment range is wide. It can be adjusted continuously and quickly under both perceptual and capacitive operating conditions, and the response speed can reach millisecond level.

4) Static operation, safe and stable, no large rotating equipment like a condenser, no wear, no mechanical noise, which will greatly increase the life of the device and improve the environmental impact.

5) After the PWM wave output by the inverter power module is filtered by the output filter, the waveform can meet the requirements, and then output through the isolation transformer with a transformation ratio of 1:2, so that the DC side voltage of the inverter power module does not need to be very high It can be suitable for reactive power compensation under the condition of high voltage level.

In summary, the utility model can greatly improve the running time and efficiency of the reactive power compensation device, reduce the maintenance workload, give full play to the dynamic and rapid adjustment function of the device, strengthen the reactive power and voltage regulation ability of the central point, and promote the regional The power grid quickly realizes reactive power balance and voltage stability, and improves the modernization and automation level of the power grid.

Description of drawings

Fig. 1 is a schematic structural diagram of a multifunctional power quality conditioner based on a voltage type inverter of the present invention.

In the figure: three-phase rectifier bridge 1, inverter power module 2, output filter 3, isolation transformer 4, sampling circuit 5, DSP controller 6, photoelectric isolation input and output circuit 7, industrial control computer 8, main circuit 9 and control circuit 10.

Fig. 2 is a schematic diagram of the DSP controller of the present invention.

In the figure: zero-crossing measurement module 6-1, sampling module 6-2, filter module 6-3, fault detection module 6-4, communication module 6-5.

Detailed ways

The structure of the multifunctional power quality regulator based on the voltage type inverter of the utility model is shown in Figure 1, the multifunctional power quality regulator based on the voltage type inverter described in the utility model is composed of the main circuit 9 and The control circuit 10 is composed. The main circuit 9 is composed of a three-phase rectifier bridge 1, an inverter power module 2, an output filter 3, an isolation transformer 4 and the like. A three-phase rectifier bridge, an inverter power module, an output filter, and an isolation transformer are sequentially connected in series. The control circuit 10 includes a sampling circuit 5 , a DSP controller 6 , a photoelectric isolation input and output circuit 7 and an industrial control computer 8 .

The main circuit 9 part of the multifunctional power quality conditioner based on the voltage type inverter includes a three-phase rectifier bridge 1, an inverter power module 2, an output filter 3, an isolation transformer 4, etc.; its control circuit 10 part mainly includes Sampling circuit 5, DSP controller 6, photoelectric isolation input and output circuit 7 and industrial control computer 8. The main feature of the DSP controller 6 is DPS2812M as the core, and at the same time integrates commonly used DSP peripheral circuits, integrating real-time processing capabilities and controller peripheral functions. The output of the three-phase rectifier bridge 1 in the main circuit 9 is connected with a voltage support capacitor C, whose function is to provide a voltage support for the device; for the inverter power module 2, an IGBT with a higher switching frequency is selected, and PWM modulation technology is used. When the power is first turned on, the six pulses of the inverter bridge are blocked, so that it is in the state of full bridge rectification, and the voltage support capacitor C is charged. The inverter power module 2 is composed of a group of three-phase bridge and two-level structure, which is controlled by PWM modulation technology. The sinusoidal voltage output by the inverter power module 2 is filtered by the output filter 3 and then connected to the grid through a three-phase isolation transformer 4 . The novel multifunctional power quality regulator can absorb or send out reactive power from the system, and it can be regarded as a controllable reactive current source.

In the control circuit 10 , the three-phase current and voltage signals of the grid are collected by the sampling circuit 5 and then input to the DSP controller 6 . The DSP controller 6 calculates and processes the collected data, outputs PWM control pulses, and the PWM control pulses are sent to the control terminal of the inverter power module 2 through the photoelectric isolation input and output circuit 7 . The industrial control computer 8 communicates with the DSP controller 6 through the RS232 interface, and is used to display the three-phase current and voltage signals of the power grid in real time, and has the functions of historical data query and fault data query.

The structure of the DSP controller of the present utility model is shown in Figure 2, and the DSP controller 6 includes a zero-crossing measurement module 6-1, a sampling module 6-2, a filter module 6-3, a fault detection module 6-4 and a communication module 6- 5.

The main function of the zero-crossing determination module 6-1 is to realize the sampling of the zero-crossing point of the synchronous signal. In order to ensure that the output voltage of the multifunctional power quality conditioner based on the voltage source inverter is synchronized with the system, the zero-crossing point of the grid voltage must be measured as the initial signal of sampling. The capture unit of the DSP event manager can capture the jump signal (signal rising or falling edge) on its input pin, so that the capture of the zero-crossing point is much easier to realize than the microcontroller.

The role of the sampling module 6-2 is to realize AC real-time sampling of grid data. According to the PWM wave calculation requirements, the sampling period is set to 156us, and the frequency is 128 times the power frequency, so that the carrier frequency can reach 128×50=6400Hz, and the carrier frequency is so high that the output harmonic components can be reduced.

The filtering module 6-3 uses a non-recursive digital filter to filter out the sampled high-frequency noise signal. The amount of calculation that needs to be completed in this function module is relatively large. The non-recursive digital filter is a type of filter realized by convolving the input signal and the unit impulse response of the filter. It can completely filter out various components whose frequency is an integer multiple of the fundamental frequency in the signal.

The fault detection module 6-4 realizes the fault detection and protection of the voltage-type inverter-based multi-functional power quality conditioner. When the IGBT of the inverter power module has faults such as overcurrent, overvoltage, overheating, and short circuit, the IGBT gate drive unit will shut off the current and output a fault signal (FO). When the fault detection module detects this signal, it will immediately generate an interrupt signal PDPINT, which prohibits the DSP from continuing to send out PWM waves.

The communication module 6-5 is used to complete the communication between the DSP controller and the industrial control computer. Exchange data (sampling data, reactive power, fault signal, etc.), these functions are realized by programming the communication port of DSP. The industrial control computer communicates with the DSP controller through the RS232 interface, which is used to display the three-phase current and voltage signals of the power grid in real time, and has the functions of historical data query and fault data query.

Claims (5)

1. based on the multifunctional electric energy quality adjustor of voltage source inverter, it is characterized in that this adjuster is made up of main circuit and control circuit; Main circuit is made up of three-phase commutation bridge, inverter power module, output filter, isolating transformer; Control circuit isolates imput output circuit by sample circuit, dsp controller, photoelectricity and industrial control computer is formed;

1) structure of each parts

Output filter is made up of inductance and electric capacity; Dsp controller (6) is provided with I, II, three ports of III, and the I port of dsp controller is the I/O input/output port; The II port is a sampling module; The III port is a communication module;

2) annexation of each parts

One end of three-phase commutation bridge links to each other with electrical network; The other end connects the inverter power module that voltage supports capacitor C; The output of inverter power module is connected with an end of output filter, and the other end of output filter connects the former limit of isolating transformer, and the secondary of isolating transformer gets access to grid;

The II port of the output termination dsp controller of sample circuit, the I port of dsp controller is isolated imput output circuit with photoelectricity and is linked to each other through optical fiber, and the output that photoelectricity is isolated imput output circuit is connected with inverter power module; The III port of dsp controller is connected through the RS232 serial ports with industrial control computer.

2. the multifunctional electric energy quality adjustor based on voltage source inverter according to claim 1 is characterized in that: described inverter power module adopts the FF450R17ME3 module of infineon.

3. the multifunctional electric energy quality adjustor based on voltage source inverter according to claim 1 is characterized in that: the turn ratio of the former secondary of said isolating transformer is 1: 2.

4. the multifunctional electric energy quality adjustor based on voltage source inverter according to claim 1 is characterized in that: described dsp controller module adopts closes the DPS2812M controller that the crowd reaches company.

5. the multifunctional electric energy quality adjustor based on voltage source inverter according to claim 1 is characterized in that: said sample circuit adopts two AD7656 chips, 16 of precision.

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