阅读说明：本技术 一种方波无刷直流风力发电机控制器 (Controller of square wave brushless direct current wind driven generator ) 是由 朴俊民 边春元 由旭 邢海洋 徐宁 于 2020-04-28 设计创作，主要内容包括：一种方波无刷直流风力发电机控制器,涉及一种风力发电机控制器,控制器包括功率模块、控制系统、上位机、机械刹车、电压检测模块、驱动电路、非换相相电流选择模块和无位置传感器检测模块；功率模块设有输入滤波和输出滤波电路；控制系统上设有主控芯片、PWM驱动电路、ADC模块、逻辑控制、位置检测和485通讯电路；上位机设有液晶显示面板、系统工作状态和机侧、网侧的实时电压电流及其功率、工作状态和故障代码；所述功率模块一端与风力发电机的输出连接,另一端与电网相连接；本发明提高了风力机组风速利用范围,并且无需卸荷单元；广泛应用于单相并网或三相并网运行的风力发电机控制领域。(A square wave brushless direct current wind driven generator controller relates to a wind driven generator controller, and the controller comprises a power module, a control system, an upper computer, a mechanical brake, a voltage detection module, a drive circuit, a non-commutation phase current selection module and a position-sensorless detection module; the power module is provided with an input filtering circuit and an output filtering circuit; the control system is provided with a main control chip, a PWM (pulse-width modulation) driving circuit, an ADC (analog-to-digital converter) module and a logic control, position detection and 485 communication circuit; the upper computer is provided with a liquid crystal display panel, a system working state, real-time voltage and current of a machine side and a network side, power of the real-time voltage and current, a working state and fault codes; one end of the power module is connected with the output of the wind driven generator, and the other end of the power module is connected with a power grid; the invention improves the wind speed utilization range of the wind turbine generator and does not need an unloading unit; the method is widely applied to the field of control of the wind driven generator in single-phase grid connection or three-phase grid connection operation.)

1. The square wave brushless direct current wind driven generator controller is characterized by comprising a power module, a control system, an upper computer, a mechanical brake, a voltage detection module, a driving circuit, a non-commutation phase current selection module and a position-sensorless detection module; the power module is provided with an input filtering circuit and an output filtering circuit; the control system is provided with a main control chip, a PWM (pulse-width modulation) driving circuit, an ADC (analog-to-digital converter) module and a logic control, position detection and 485 communication circuit; the upper computer is provided with a liquid crystal display panel, a system working state, real-time voltage and current of a machine side and a network side, power of the real-time voltage and current, a working state and fault codes; one end of the power module is connected with the output of the wind driven generator, and the other end of the power module is connected with a power grid; the control system drives the power module through the PWM module, the ADC module detects the voltage of a power grid and the current of a motor, the terminal voltage detection circuit detects a position signal, and the communication module is connected with an upper computer; the control system is also connected with the control end of the IGBT of the power module, and the control end of the IGBT is subjected to pulse width control according to the output voltage and current of the power module, so that overvoltage, undervoltage and overcurrent protection and automatic recovery functions are realized; the generator adopts a PWM _ OFF modulation mode.

2. The controller of the square wave brushless direct current wind driven generator according to claim 1, wherein the control system is communicated with an upper computer through a 485 communication circuit, and the upper computer displays the operation parameters of the controller in real time, wherein the operation parameters comprise power generation time, power generation capacity, machine side voltage current and power, network side voltage current and power, bus voltage, wind speed, controller operation state and fault codes, so that local or remote monitoring and recording of operation data are realized; the controller has a high step-up ratio, and can be normally connected with the power generation grid even at low wind speed.

3. The controller of claim 1, wherein the control system collects the machine side voltage and current through the voltage sensor and the current sensor to calculate the machine side power generation, controls the motor speed through the maximum tracking power, and calculates the maximum current drawn by the machine side from the machine side in the speed loop, so that the power generated by the machine side is all incorporated into the grid through the power module.

4. The controller of claim 1, wherein when a voltage drop occurs in the grid, an optimal solution is found between the grid voltage threshold and the grid-side current upper limit value according to the instantaneous power theory, and the grid can normally generate power without unloading the unit even if the grid voltage drops.

5. The controller of claim 1, wherein when the wind speed is too high, the converter control system sends a mechanical brake enable command and a machine side star blocking command to stop the wind turbine at zero speed, and the controller is automatically powered off.

Technical Field

The invention relates to a generator controller, in particular to a square wave brushless direct current wind driven generator controller.

Background

Wind energy is taken as a clean renewable energy source, the abundance of the wind energy is huge, the wind energy is more and more emphasized by various countries in the world under the background that fossil energy is increasingly scarce and the environment protection situation is increasingly severe, and a wind energy controller is taken as a main control part of a wind power generation system and plays an extremely important role in wind power generation.

The grid-connected wind driven generator controller is the core of a grid-connected wind power generation technology, and has the main functions of rectifying and filtering three-phase alternating voltage output by wind power generation, transmitting the direct current voltage to a grid-connected inverter after rectification and filtering, detecting the magnitude of the output voltage and working current, and braking through a braking circuit when the output voltage or the output current exceeds a set voltage or current to stop the wind driven generator, so that the inverter is prevented from being damaged by overvoltage or overcurrent.

The small-sized wind driven generator has the advantages that the effective power generation time is short, and the available wind speed range is small, so that the cut-in wind speed is reduced, the cut-out wind speed is increased, the power generation time is prolonged, the wind energy utilization rate and the equipment utilization rate are increased, and the generated energy is increased.

The traditional wind generator controller needs to add a resistance unloading unit, so that the system is redundant and complex, and the cost of the controller is increased.

The starting wind speed of a common small-sized wind driven generator is about 5m/s, the stopping wind speed is about 20m/s, namely 5-20m/s is an effective wind area, the boosting ratio is about 4 times, and the wind energy cannot be well utilized. If the rated rotating speed of the generator is reduced, the generator generates electricity at low wind speed, but the low-rotating-speed generator has large volume and overhigh manufacturing cost, so the low-rotating-speed generator can not effectively improve the generating efficiency of the wind driven generator.

Disclosure of Invention

The invention aims to provide a controller of a square wave brushless direct current wind driven generator, which is a novel controller of the square wave brushless direct current motor wind driven generator with a high step-up ratio and without a resistance unloading unit. And a resistor unloading unit is not needed, and the system cost is reduced.

The purpose of the invention is realized by the following technical scheme:

a square wave brushless direct current wind driven generator controller comprises a power module, a control system, an upper computer, a mechanical brake, a voltage detection module, a driving circuit, a non-commutation phase current selection module and a position-sensorless detection module; the power module is provided with an input filtering circuit and an output filtering circuit; the control system is provided with a main control chip, a PWM (pulse-width modulation) driving circuit, an ADC (analog-to-digital converter) module and a logic control, position detection and 485 communication circuit; the upper computer is provided with a liquid crystal display panel, a system working state, real-time voltage and current of a machine side and a network side, power of the real-time voltage and current, a working state and fault codes; one end of the power module is connected with the output of the wind driven generator, and the other end of the power module is connected with a power grid; the control system drives the power module through the PWM module, the ADC module detects the voltage of a power grid and the current of a motor, the terminal voltage detection circuit detects a position signal, and the communication module is connected with an upper computer; the control system is connected with the control end of the IGBT of the power module, and performs pulse width control on the control end of the IGBT according to the output voltage and current of the power module, so as to realize overvoltage, undervoltage and overcurrent protection and automatic recovery functions; the generator adopts a PWM _ OFF modulation mode.

According to the square wave brushless direct current wind driven generator controller, the control system is communicated with an upper computer through a 485 communication circuit, and the upper computer displays the operation parameters of the controller in real time, wherein the operation parameters comprise power generation time, power generation capacity, machine side voltage current and power, network side voltage current and power, bus voltage, wind speed, controller operation state and fault codes, and local or remote monitoring and recording of operation data are realized; the controller has a high step-up ratio, and can be normally connected with the power generation grid even at low wind speed.

According to the controller of the square wave brushless direct current wind driven generator, the control system collects the voltage and current of the generator side through the voltage sensor and the current sensor, so that the power generated by the generator side is calculated, the control of the rotating speed of the motor is realized through the maximum tracking power, the maximum current extracted from the generator side at the network side is calculated in the speed ring, and the power generated by the generator side is all merged into a power grid through the power module.

According to the controller of the square wave brushless direct current wind driven generator, when a voltage drop occurs to a power grid, an optimal solution is found in a power grid voltage threshold value and a grid side current upper limit value according to an instantaneous power theory, and even if the power grid voltage drops, normal power generation can be carried out without unloading a unit.

When the wind speed is too high, the converter control system can send out a mechanical brake enabling command and a machine side star sealing command, so that the wind driven generator stops at zero speed, and the controller is automatically powered off.

The invention has the advantages and effects that:

the controller has high voltage boosting ratio, and the generator controller has about 10 times of voltage boosting ratio, so that the wind speed utilization range is effectively improved; the controller can normally generate power and be connected to the grid even at low wind speed, so that the wind speed utilization range is enlarged, and the power generation efficiency of the wind generating set is effectively improved.

The generator controller does not need a resistance unloading unit, and reduces the system cost.

The generator controller is compatible with single-phase grid connection and three-phase grid connection modes.

The generator controller of the invention does not need a position sensor, adopts a position-free algorithm and reduces the volume and the cost of the controller.

The main control unit has the functions of overvoltage, undervoltage, overcurrent and overtemperature protection and self-recovery. The main control unit has a maximum power tracking function.

Drawings

FIG. 1 is a block diagram of the principle structure of the present invention;

FIG. 2 is a block diagram of the process of the present invention in the event of a grid voltage sag;

FIG. 3 is a block diagram of the main loop process of the present invention.

Detailed Description

The present invention will be described in detail with reference to the embodiments shown in the drawings.

The invention discloses a square wave brushless direct current motor wind driven generator controller which comprises a power module, a control system, an upper computer, a mechanical brake, a voltage detection module, a driving circuit, a non-commutation phase current selection module and a position-sensorless detection module. The power module is provided with an input filtering circuit and an output filtering circuit; the control system is provided with a main control chip, a PWM (pulse-width modulation) driving circuit, an ADC (analog-to-digital converter) module and a logic control, position detection and 485 communication circuit; the controller adopts a square wave brushless direct current motor as a wind driven generator. And the mechanical brake device locks the wind wheel.

As shown in fig. 1, the wind turbine controller includes a power module, a control system, an upper computer, a mechanical brake, a voltage detection module, a driving circuit, a non-commutation phase current selection module, and a position-sensorless detection module. The power module is provided with an input filtering circuit and an output filtering circuit; the control system is provided with a main control chip, a PWM (pulse-width modulation) driving circuit, an ADC (analog-to-digital converter) module and a logic control, position detection and 485 communication circuit; the upper computer is provided with a liquid crystal display panel, a system working state, real-time voltage and current of a machine side and a network side, power of the real-time voltage and current, a working state and fault codes of the real-time voltage and current. And one end of the power module is connected with the output of the wind driven generator, and the other end of the power module is connected with a power grid. The control system drives the power module and the ADC module through the PWM module to detect the voltage of a power grid and the current of a motor, the terminal voltage detection circuit detects a position signal, and the communication module is connected with an upper computer. The control system is also connected with the control end of the IGBT of the power module, and the control end of the IGBT is subjected to pulse width control according to the output voltage and current of the power module, so that overvoltage, undervoltage and overcurrent protection and automatic recovery functions are realized.

The control system is communicated with the upper computer through a 485 communication circuit, and the upper computer displays the operation parameters of the controller in real time, wherein the operation parameters comprise power generation time, power generation capacity, machine side voltage current and power, network side voltage current and power, bus voltage, wind speed, controller operation state and fault codes, and local or remote monitoring and recording of operation data are realized.

The square wave brushless direct current motor wind power generation system adopts the square wave brushless direct current motor as a wind power generator.

The square wave brushless direct current motor wind driven generator controller does not need a resistance unloading unit, a control system collects the voltage and current of a generator side through a voltage sensor and a current sensor so as to calculate the power generated by the generator side, then the control on the rotating speed of the motor is realized through the maximum tracking power, so that the generator works at an optimal working point, the maximum current extracted from the generator side by the network side is calculated in a speed ring, and the power generated by the generator side is all merged into a power grid through a power module.

When the voltage of the power grid drops, according to the instantaneous power theory, the output current of the wind turbine generator is increased, and when the voltage of the power grid drops to a threshold value, the system can enter shutdown protection. According to meticulous calculation, an optimal solution is found in a grid voltage threshold value and a grid side current upper limit value, and power can be normally generated without unloading a unit even if the grid voltage drops.

When the wind speed is too high, the converter control system can send out a mechanical brake enabling command and a machine side star sealing command, so that the wind driven generator stops at zero speed, the controller is automatically powered off, the inverter damage caused by overspeed, overvoltage and overcurrent is avoided, and after 10 minutes, the controller can be restarted and judges whether the wind speed is suitable for starting.

As shown in fig. 3, after the chip is powered on, the program first enters an initialization stage, which is mainly to block the output of the PWM signal, define the function of the GPIO pin of the DSP, initialize the operations of the ADC, the I/O, PWM output ports and other related ports, configure the chip interrupt system, and finally initialize the variables in the program.

After the initialization is finished, the system enters a dead loop, and different running states of the system are switched according to the value of the state variable in a finite state machine mode. The Idle state is prepared before the system is started, the system starts to Run in the Start state, the Run state is the system running state, and the Stop state is the system stopping state, wherein a plurality of variables are reinitialized. The Fault state is a system error reporting state, and if the Fault state is in the system error reporting state, the PWM is blocked, so that the whole system is protected.

Taking the brushless DC motor adopting PWM _ OFF modulation mode as an example, the circuit principle of the brushless DC motor rectifier in the switching state is analyzed.

During the switch tube switches on, the electric current that flows through inductance and switch tube increases gradually, and inductance current variable quantity is:

；

whereinIs the sum of the conducting opposite potentials in the circuit,in order to reduce the voltage of the switch tube,is a diode drop. When the switch tube is turned off, the inductive current provides energy for the bus, and the change quantity of the inductive current is

；Is the boosted bus voltage.

The inductive current is not changed at the moment of switching on and switching off the switch tube, so:；(ii) a (ii) a Therefore, the relationship among the back electromotive force of the motor, the bus voltage and the duty ratio D is as follows:；

if voltage drops of the switch tube and the diode are neglected, the relation between the back electromotive force and the bus voltage is as follows:；（1）

the duty ratio ranges from 0 to 1, so in theory, when the duty ratio is 1, the square wave brushless direct current generator adopts a PWM-like control strategy, and the boost ratio can reach infinity.

The DC voltage value output by the permanent magnet synchronous motor after being rectified by the diodeThe relation between the effective value U of the phase voltage of the permanent magnet synchronous motor and the amplitude E of the phase voltage is as follows:；

the DC voltage value output by the brushless DC motor after being rectified by the diodeEqual to the line voltage thereof, so that the output DC voltage valueThe relation with the phase voltage amplitude E is；

The rectified DC voltage of the brushless DC motorAnd DC voltage of permanent magnet synchronous motorSubstituting the above formula (1) to obtain

；

According to the formula, when the counter electromotive force amplitude of the brushless direct current motor is equal to that of the permanent magnet synchronous motor and the duty ratio is equal, the bus voltage boosting of the brushless direct current motor is about 21% higher than that of the permanent magnet synchronous motor.

In practical application, the boost ratio cannot reach infinity due to the influence of various factors such as the equivalent series resistance of the inductor in the circuit. The boost ratio of a common brushless direct current wind power generation system is about 2 times, and the boost ratio of the common brushless direct current wind power generation system is more than 10 times according to the power generation capacity of the brushless direct current motor, so that the system can more fully utilize wind energy, and the operating wind speed range of the wind power system is widened.