CN203243245U

CN203243245U - Novel DC/AC inverter based on BUCK-BOOST circuit

Info

Publication number: CN203243245U
Application number: CN2013200113941U
Authority: CN
Inventors: 陈荣; 张加胜
Original assignee: China University of Petroleum East China
Current assignee: China University of Petroleum East China
Priority date: 2013-01-10
Filing date: 2013-01-10
Publication date: 2013-10-16
Anticipated expiration: 2023-01-10

Abstract

A novel DC/AC inverter based on a BUCK-BOOST circuit is mainly composed of a direct current source input 1, a direct current source input 2, a system given input, a feedback signal, a controller, a PWM signal generator, an output signal detection unit, a load and a main circuit, etc. The novel DC/AC inverter which is based on the BUCK-BOOST circuit can achieve pressure-reducing and pressure-boosting output functions. The input voltage range is widened. Meanwhile, by using the mature soft switch technology, the novel DC/AC inverter can effectively lower device switch loss. The novel DC/AC inverter adopting two direct current sources used for simultaneous power supplying and respectively generating positive and negative half-waves outputting sinusoidal signals facilitates modularization.

Description

A kind of novel DC/AC inverter based on the BUCK-BOOST circuit

Technical field

The present invention proposes a kind of novel DC/AC inverter based on the BUCK-BOOST circuit, can be widely used in wind power generation, solar power generation and other distributed generation system, also applicable to fields such as electric automobile and ac motor speed control devices.

Background technology

The DC/AC converter is called again inverter, its effect is to utilize turning on and off of semiconductor switching device, DC power supply is converted to all controllable simple alternating current out-put supplies of amplitude and frequency, be used for driving alternating current machine or as ac uninterrupted power supply, perhaps directly be connected with electrical network, the realization system is incorporated into the power networks.Along with the growing tension of global energy supply, people are to adopting the distributed generation technology growing interest of regenerative resource.The efficient operation of wind power generation, solar power generation and fuel cell distributed electricity generation system all depends on power electronic technology.But, instantaneous input power and the change range of input voltage of distributed generation system self are larger, thereby very high to the requirement of the key link-voltage source inverter of transformation of electrical energy, as, require system high efficiency operate power wide ranges, have wide-range input voltage adaptive capacity etc.Traditional DC/AC voltage source inverter has the shortcoming of self: the amplitude maximum of output voltage can only reach the DC input voitage value on the one hand, and the inverter operating efficiency obviously descends along with the minimizing of power output; On the other hand, DC-AC transducer commonly used adopts the bridge-type main circuit more, is input as single input, particularly has certain shortcoming aspect the soft switch technique application technology.In order to address the above problem, need between DC power supply and inverter, increase the Boost booster circuit to adapt to the variation of DC input voitage, increase one-level hard switching DC/DC transformation of electrical energy, overall efficiency and reliability must be affected; For life-span of prolonging power electronic device and the reliability of work, need to consider the soft problem that turns on and off of device.

Summary of the invention

The present invention proposes a kind of DC-AC translation circuit based on the BUCK-BOOST circuit, system adopts two inputs, one output form, both can realize the automatic adjusting of output voltage height, to satisfy the requirement of wide input voltage, can take full advantage of again the ripe soft technology of cut-offfing of step-up/step-down circuit, reduce to greatest extent the loss of device break-make, effectively prolong the useful life of switching device.

Novel DC/AC inverter based on the BUCK-BOOST circuit is comprised of two-way independent direct current input power, the given signal of system, feedback detection signal, controller, pwm signal generator, output signal detecting unit, load and main circuit; Two-way independent direct current input power is the main circuit power supply of inverter; The given signal of system is sent into controller after doing difference with the feedback detection signal, and controller output control pwm signal pulsewidth produces pwm signal and drives opening and turn-offing of main circuit device through the pwm signal generator again; The pwm signal generator is realized by triangular wave carrier circuit and reference signal analog comparator; Controller is by the simulation control of PID the electric circuit constitute.

Description of drawings

Fig. 1 is converter each several part pie graph;

Fig. 2 is DC-AC inverter main circuit topology;

Fig. 3 BUCK-BOOST circuit working pattern 1;

Fig. 4 BUCK-BOOST circuit working pattern 2;

Fig. 5 is that system voltage stagnates chain rate than the closed-loop control block diagram;

Fig. 6 is the open loop PD of system control block diagram;

Fig. 7 is the closed loop PI of system control block diagram;

Specific implementation method

Fig. 1 is DC/AC inverter each several part pie graph.Inverter mainly is comprised of DC power supply input 1, DC power supply input 2, the given input 3 of system, feedback signal 4, controller 5, pwm signal generator 6, output signal detecting unit 7, load 8 and main circuit 9 etc.Wherein DC power supply input 1 and the DC power supply input 2 main circuit power supplies as inverter are powered to main circuit; Given input signal 3 is given signals of system output signal, does with feedback signal 4 and sends into controller 5 after poor, generates the pwm signal pulse-width control signal, produces pwm signals and drives opening and turn-offing of main circuit device through pwm signal generator 6 again; Output signal detecting unit 7 is for generation of feedback signal.The given input 3 of system, feedback signal 4, controller 5, pwm signal generator 6 can be comprised of simulations such as potentiometer, analog pid controller and triangle wave signals when specific implementation, also can be comprised of digital circuits such as button, CPU.

Figure 2 shows that main circuit topology figure.Circuit is by just organizing and two BUCK-BOOST the electric circuit constitutes of anti-group.Just organizing and be responsible for providing reverse voltage, anti-group is responsible for producing forward voltage.

S ₁During conducting, sustained diode ₁Cathode voltage be input voltage E ₁, and capacitor C during stable state ₁Be charged to a certain negative voltage, caused the anti-partially cut-off of diode, because constant voltage E ₁Be applied to L ₁On, so its electric current is with di/di=E ₁/ L ₁Linear rising of slope.After conducting a period of time, the electric current of inductance L 1 reaches maximum, and its equivalent electric circuit as shown in Figure 3.Work as S ₁During shutoff, inductive energy storage discharges with the self induction electromotive force form, sustained diode ₁Conducting, the linear decline of electric current is also given capacitor charging, and its equivalent electric circuit is as shown in Figure 4.Inductive current i _LBy filter capacitor C ₁, load inductance L and load resistance R, load voltage mean value and input voltage E ₁Polarity is opposite.Because adopt the BUCK-BOOST circuit, output voltage can be higher than input voltage, also can be lower than input voltage.

In order to realize the DC-AC converter function, need S ₁/ S ₂With S ₃/ S ₄Collocation is used.As the counter-portion timesharing that needs output voltage, switching device S ₂Normal open, switching device S ₁Play the function of regulation output voltage.Equally, when needing the forward part of output voltage, switching device S ₄Normal open, switching device S ₃Play the function of regulation output voltage.Conventional BUCK-BOOST circuit, be mainly used to carry out the DC-DC conversion, require the output voltage fluctuation little, antijamming capability is strong, and when being used as the DC-AC converter, require output voltage adjustable continuously, pursuit be quick trace performance, specific implementation can realize by the duty ratio of regulating in real time the BUCK-BOOST circuit.

In order to realize output signal to the high-quality tracking of given sinusoidal signal, control impuls generation method commonly used has hysteresis loop tracking control method and high frequency triangle wave modulator approach.Hysteresis loop tracking control method is with output signal and given sinusoidal reference signal, compare in real time, can realize that output signal is to the real-time tracking of input signal, the category that belongs to the input and output closed-loop control, shortcoming is that the operation time of system is unfixing, impact on system output signal is larger, and its corresponding control block diagram as shown in Figure 5.In order to guarantee the tracking effect of output voltage, when practical application, adopt the voltage chain rate that stagnates to determine the operating time, the high-frequency signal by fixed frequency and duty ratio in the operating time.The high frequency modulated method is that triangle modulating wave and sinusoidal reference ripple compare in real time, produces the control impuls that needs, i.e. so-called SPWM control, and its advantage is that the switching device operating frequency of system is fixed, and is convenient to the filtering harmonic signal.But be the positive and negative half-wave by positive and negative two groups of circuit sine wave outputs when utilizing the BUCK-BOOST circuit to realize sine wave, when not being very high, the requirement of offset of sinusoidal waveform quality adopts open loop control, directly usage ratio differential control, the rapidity that had not only guaranteed the quality that waveform output is sinusoidal but also can well guarantee to respond, but the amplitude of output voltage is subject to the control of input voltage, and corresponding control block diagram as shown in Figure 6.If the requirement to output voltage waveforms is very high, can adopt the output voltage closed-loop control, directly adopt PI control, effectively guarantee the constant impact that not changed by input voltage of output voltage, its control block diagram is as shown in Figure 7.When the baseline sinusoidal wave Vref increase of starting from scratch, output voltage is followed the tracks of reference voltage and is changed, and obtains error signal Ve by pi regulator, and Ve produces pwm signal with triangle wave, and pwm signal is controlled and cooperated control with given signal zero cross signal again, control switch device S ₁, S ₂, S ₃, S ₄Break-make, thereby export corresponding voltage signal.

The feature of this explanation can be summarized as: the two dc power supply input, and the output of single cross stream, output voltage can raise and also can reduce.

Claims

1. based on the novel DC/AC inverter of BUCK-BOOST circuit, it is characterized in that its main circuit power supply is that main circuit output is one tunnel AC power by two groups of independent DC power supply power supplies; Main circuit topology can be realized the output of ascending, descending pressure by positive and negative two groups of BUCK-BOOST the electric circuit constitutes; Novel DC/AC inverter is comprised of two-way independent direct current input power, the given signal of system, feedback detection signal, controller, pwm signal generator, output signal detecting unit, load and main circuit; Two-way independent direct current input power is the main circuit power supply of inverter; The given signal of system is sent into controller after doing difference with the feedback detection signal, and controller output control pwm signal pulsewidth produces pwm signal and drives opening and turn-offing of main circuit device through the pwm signal generator again; The pwm signal generator is realized by triangular wave carrier circuit and reference signal analog comparator; Controller is by the simulation control of PID the electric circuit constitute.