A novel control device and method for broadening the input voltage range

Abstract

A novel control device and method for widening input voltage range, the device comprising a transformer TD, an error amplifier EAP1, an error amplifier EAP2, a PI regulator PI1, a PI regulator PI2, a variable frequency sawtooth wave generator SAW, a comparator CMP, an inverter NOT, a multiplier AND1, a multiplier AND2, a drive circuit DR1, a drive circuit DR2 and a monostable multivibrator generator MONO, and the control method adjusts the output voltage by simultaneously adjusting the working frequency and the duty cycle. Through the implementation of the application, the input voltage range of the double-output LLC resonant converter is widened, the working frequency and the duty cycle can be changed simultaneously during operation, and after the input voltage jumps or the output branch load jumps, the working frequency of the control method is closer to the resonant frequency compared with the working frequency of the variable frequency control.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of data switch converter, and particularly relates to a novel input voltage range widening control device and method. BACKGROUND

[0002] As the source power of electronic equipment, the power supply bears the important role of electric energy conversion. With the continuous improvement of the requirements of high efficiency and low electromagnetic interference (EMI), the double-output LLC resonant converter gradually becomes the focus of the development of power supply technology. As a new type of soft switching technology, the double-output LLC resonant converter has the advantages of low EMI, zero voltage turn-on (ZVS) of the switching tube, zero voltage turn-off (ZCS) of the rectifier diode, and is widely used in the power supply industry. The main control mode of the double-output LLC resonant converter is usually frequency control, but under this control mode, the input voltage range is narrow, and under the light load condition, the working frequency deviates from the resonant frequency more, which leads to the system unable to realize high efficiency operation. SUMMARY

[0003] To solve the above technical problems, the application provides a new control method and device for widening the input voltage range. The control method adjusts the output voltage by adjusting the working frequency and the duty cycle at the same time, realizes wide range output, has high engineering application value, and at the same time, the control method is not only used in the double-output LLC resonant converter, but also can be applied to the LLC resonant converter.

[0004] The application is realized through the following technical schemes.

[0005] The application provides a novel input voltage range widening control device, which comprises a transformer TD, an error amplifier EAP1, an error amplifier EAP2, an error amplifier EAP2, a PI regulator PI1, a PI regulator PI2, a variable frequency sawtooth wave generator SAW, a comparator CMP, an inverter NOT, a multiplier AND1, a multiplier AND2, a drive circuit DR1, a drive circuit DR2 and a monostable multivibrator generator MONO; the transformer TD is a full-bridge LLC resonant transformer, is provided with control switching tubes Q1-Q4, the output end of the drive circuit DR1 is connected with the control switching tubes Q1 and Q4, the conduction of the control switching tubes Q1 and Q4 is controlled, the output end of the drive circuit DR2 is connected with the control switching tubes Q2 and Q3, the conduction of the control switching tubes Q2 and Q3 is controlled; the output end of the transformer TD is connected with the input ends of the error amplifiers EAP1 and EAP2, the output end of the error amplifier EAP1 is connected with the input end of the PI regulator PI1, the output end of the PI regulator PI1 is connected with the input end of the variable frequency sawtooth wave generator SAW; the output end of the error amplifier EAP2 is connected with the input end of the PI regulator PI2, the output end of the PI regulator PI2 is connected with the input end of the variable frequency sawtooth wave generator SAW, and the output end of the variable frequency sawtooth wave generator SAW is connected with the input end of the comparator CMP; the output end of the comparator CMP is connected with the input end of the monostable multivibrator generator MONO, the input end of the inverter NOT and the input end of the multiplier AND1, the output end of the inverter NOT is connected with the input end of the multiplier AND2, the output end of the monostable multivibrator generator MONO is connected with the input ends of the multiplier AND1 and the multiplier AND2, the output end of the multiplier AND1 is connected with the drive signal input end of the drive circuit DR1, and the output end of the multiplier AND2 is connected with the drive signal input end of the drive circuit DR2.

[0006] Further, the application further comprises a limiter LIM, the input end of the limiter LIM is connected with the output end of the PI regulator PI1, and the output end is connected with the input end of the variable frequency sawtooth wave generator SAW.

[0007] Further, the input ends of the error amplifiers EAP1 and EAP2 are further connected with a voltage reference value Vref1.

[0008] Further, the transformer TD is connected with an input voltage V in .

[0009] A control method of a novel input voltage range widening control device, comprising the following steps:

[0010] Step 1, at any cycle starting moment, the output end of the transformer TD outputs a sampling output voltage Voa, which is processed by the error amplifiers EAP1 and EAP2 to generate amplified error signals Ve1 and Ve2, and is input to the input ends of the PI regulators PI1 and PI2 respectively;

[0011] Step 2, the error signal Ve1 is input to the input end of the frequency conversion sawtooth wave generator SAW after being regulated by the PI regulator PI1, to generate a frequency conversion sawtooth wave signal VSAW;

[0012] Step 3, the error signal Ve2 is input to the PI regulator PI2 to generate a signal VPI2 after being regulated by the PI regulator PI2;

[0013] Step 4, the signal VSAW is input to the positive end of the comparator CMP, and the signal VPI2 is input to the negative end of the comparator CMP, and the comparator CMP outputs a signal to the signal input end of the monostable multivibrator MONO, the input end of the multiplier AND1 and the input end of the inverter NOT after processing;

[0014] Step 5, the Q end signal Vdead of the monostable multivibrator MONO is input to the multiplier AND1, and the multiplier AND1 outputs a signal to the drive circuit DR1 after processing the output signal of the comparator CMP and the Q end signal Vdead of the monostable multivibrator MONO, and the drive circuit DR1 outputs a drive signal to control the conduction of the control switch tubes Q1 and Q4;

[0015] Step 6, the Q end signal Vdead of the monostable multivibrator MONO is input to the multiplier AND2, and the output end signal of the inverter NOT is input to the multiplier AND2, and the multiplier AND2 outputs a signal to the drive circuit DR2 after processing the output end signal of the inverter NOT and the Q end signal Vdead of the monostable multivibrator MONO, and the drive circuit DR2 outputs a drive signal to control the conduction of the control switch tubes Q2 and Q3.

[0016] Further, in step 1, when the error amplifier EAP1 processes the signal, a voltage reference value Vref1 is also input, and the error amplifier EAP1 processes the sampling output voltage Voa and the voltage reference value Vref1 to generate the amplified error signal Ve1.

[0017] Further, in step 1, when the error amplifier EAP2 processes the signal, a voltage reference value Vref1 is also input, and the error amplifier EAP2 processes the sampling output voltage Voa and the voltage reference value Vref1 to generate the amplified error signal Ve2.

[0018] Further, in step 2, the error signal Ve1 is input into a limiter LIM after being regulated by a PI regulator PI1, and then the output signal of the limiter LIM is input into an input terminal of a variable frequency sawtooth wave generator SAW.

[0019] The present application has the advantages of: (1) widening the input voltage range of the double-output LLC resonant converter; (2) simultaneously changing the working frequency and the duty cycle; (3) after the input voltage jumps or the output branch load jumps, the working frequency of the novel control method is closer to the resonant frequency than the working frequency of the variable frequency control. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a system structure diagram of the present application;

[0021] Figure 2 is a circuit structure block diagram when the present application adopts the double-output LLC resonant converter;

[0022] Figure 3 is a waveform diagram of the output voltage, the resonant inductance, the excitation inductance and the switch device control pulse of the output branch 1 when the present application adopts the double-output LLC resonant converter;

[0023] Figure 4 is a control timing diagram of the control device of the present application;

[0024] Figure 5 is the output voltage waveform of the double-output LLC resonant converter controlled by the traditional CMP output signal when the input voltage jumps from 400V to 300V;

[0025] Figure 6 is the output voltage waveform of the double-output LLC resonant converter controlled by the traditional CMP output signal when the input voltage jumps from 400V to 250V;

[0026] Figure 7 is the output voltage waveform of the present application when the input voltage jumps from 400V to 250V. DETAILED DESCRIPTION

[0027] The technical solutions of the present application are further described below, but the scope of protection is not limited to the description.

[0028] As Figure 1 shown, one specific embodiment of the present application is a novel input voltage control double-output LLC resonant converter control method and device, which is composed of a converter TD and a control device of switch tubes Q1, Q2, Q3 and Q4. The output voltage V oaThe following components are connected in sequence: error amplifier EAP1, PI regulator PI1, limiter LIM, frequency converter sawtooth wave generator SAW, comparator CMP, and EAP1 is also connected to the reference voltage V. ref1 Sampled output voltage V oa The error amplifier EAP2, PI regulator PI2, comparator CMP, and reference voltage V are connected in sequence. ref1 The output of the CMP is connected in sequence to a monostable multivibrator (MONO), multipliers AND1 and AND2, driving DR1 and DR2. AND1 is also connected to the Q input of the TGR, and AND2 is connected to the Q input signal of the TGR after passing through a NOT gate. oa DR1 and DR2 are respectively connected to the dual-output LLC resonant converter.

[0029] In this example, the converter TD is a dual-output LLC resonant converter, and its working process and principle are as follows.

[0030] The working process and principle of the control device using variable frequency and variable duty cycle control:

[0031] like Figure 2 As shown, at the start of any cycle, the output voltage V oa and voltage reference value V ref1 The error signal V is amplified by the error amplifier EAP1. e1 V e1 The signal, after being regulated by the PI1 regulator, is limited by the LIM limiter and then input into the sawtooth wave generator (SAW) to generate a sawtooth wave signal V whose frequency can be changed. SAW V SAW The input is given to the positive terminal of comparator CMP; the output voltage V oa and voltage reference value V ref1 The error signal V is amplified by error amplifier EAP2. e2 V e2 The output signal V after being regulated by the PI2 regulator PI2 The input is given to the negative terminal of the comparator CMP; the output signal of CMP is given to the signal input terminal of the monostable multivibrator MONO, and the signal V at the Q terminal of MONO is also given. dead The input is fed into multiplier AND1, and the CMP output signal is also fed into multiplier AND1. dead The signal multiplied by the CMP output signal is input to the driver circuit DR1, which controls the conduction of switching transistors Q1 and Q4, and the signal V at the Q terminal of MONO. dead The CMP output signal is input to multiplier AND2, and then input to multiplier AND2 via an inverter NOT. deadThe signal obtained by multiplying the CMP output signal and the signal through the inverter is input to the drive circuit DR2 to control the conduction of the switching transistors Q2 and Q3.

[0032] Figure 3 The output voltage waveform of the double-output LLC resonant converter controlled by the novel method of widening the input voltage range is shown in the figure. Figure 3 In the period T on , the switching transistors Q1 and Q4 are on and the switching transistors Q2 and Q3 are off, the current I Lr flows through the resonant inductor and the current I Lm flows through the magnetizing inductor. No resonance occurs at this time, and the energy flows to the secondary side of the transformer, and the output voltage V oa rises. In the period T off , the switching transistors Q2 and Q3 are on and the switching transistors Q1 and Q4 are off, the current I Lr flows through the resonant inductor and the current I Lm flows through the magnetizing inductor. No resonance occurs at this time, and the energy flows to the secondary side of the transformer, and the output voltage V oa rises. After a period of energy transmission, the currents I Lr and I Lm resonate, and the output voltage V oa begins to drop.

[0033] Figure 4 The control timing diagram of the control device is shown in the figure. Figure 4 At the beginning of each switching period, the variable-frequency sawtooth generator SAW generates a variable-frequency sawtooth signal V SAW , the sampling output voltage V oa is compared with the reference voltage V ref1 through the error amplifier to generate an error signal V e2 , and the signal V PI2 obtained after the adjustment of the regulator PI2 is compared with V SAW and V PI2 through the comparator CMP. When V SAW is less than V PI2 , a high-level signal is obtained, and the switching transistors Q1 and Q4 are turned on and the switching transistors Q2 and Q3 are turned off after the high-level signal is input to the drive circuit. At this time, the output voltage V oa begins to rise. When V SAW is greater than V PI2 , a low-level signal is obtained, and the switching transistors Q2 and Q3 are turned on and the switching transistors Q1 and Q4 are turned off after the low-level signal is input to the drive circuit. At this time, the output voltage V oa begins to drop after a period of rise. When the input voltage changes, the variable-frequency sawtooth generator SAW generates a signal V SAW with a frequency different from V PI2The magnitude of the voltage changes simultaneously, causing the converter's operating frequency and duty cycle to change simultaneously, thereby controlling the output voltage to achieve stability.

[0034] The method of this invention was simulated and analyzed in the time domain using PSIM simulation software, and the results are as follows.

[0035] Figures 5-7 To employ frequency conversion control and implement this invention in a dual-output LLC resonant converter at an input voltage V in The time-domain simulation waveform of the output voltage under varying conditions. Figure 6 , Figure 7 The time-domain simulation waveforms of the output voltage when the input voltage jumps from 400V to 300V and from 400V to 250V under strain frequency control are respectively presented. Figure 7 The figure shown is a time-domain simulation waveform of the output voltage when the input voltage changes from 400V to 250V under the control of this invention. Figure 5 In the middle, the input voltage V of the frequency conversion controlled dual-output LLC resonant converter is... in After switching from 400V to 300V, the output voltage Voa of output branch 1 enters a new stable state after 4.56ms, and the output voltage Vob of output branch 2 enters a new stable state after 4.54ms. Figure 6 In the middle, the input voltage V of the frequency conversion controlled dual-output LLC resonant converter is... in After switching from 400V to 250V, the output voltage cannot reach a new stable state; Figure 7 In this context, the input voltage V of the dual-output LLC resonant converter is... in After switching from 400V to 250V, the output voltage Voa of output branch 1 enters a new stable state after 3.24ms, and the output voltage Vob of output branch 2 enters a new stable state after 3.02ms. Figure 5 The simulation conditions are: input voltage V in =400V, voltage reference value V ref1 =420V、V ref2 =24V, resonant inductor L r =12μH, magnetizing inductance L m =54μH, resonant capacitance C r =204μF, filter capacitor C o1 =200μF, C o2 =200μF, parasitic resistance R esr1 =10mΩ, R esr2 =10mΩ, load resistance R a =21Ω, R b =1.2Ω.

Claims

1. A novel control device for widening the input voltage range, characterized in that: It includes a converter TD, error amplifier EAP1, error amplifier EAP2, PI regulator PI1, PI regulator PI2, frequency conversion sawtooth wave generator SAW, comparator CMP, inverter NOT, multiplier AND1, multiplier AND2, drive circuit DR1, drive circuit DR2, and monostable multi-oscillator MONO. The converter TD is a full-bridge LLC resonant converter, equipped with control switches Q1~Q4. The output terminal of the drive circuit DR1 is connected to the control switches Q1 and Q4 to control the conduction of control switches Q1 and Q4. The output terminal of the drive circuit DR2 is connected to the control switches Q2 and Q3 to control the conduction of control switches Q2 and Q3. The output of the converter TD is connected to the inputs of error amplifiers EAP1 and EAP2. The output of error amplifier EAP1 is connected to the input of PI regulator PI1, and the output of PI regulator PI1 is connected to the input of frequency converter sawtooth wave generator SAW. The output of error amplifier EAP2 is connected to the input of PI regulator PI2, and the output of PI regulator PI2 is connected to the input of comparator CMP. The output of frequency converter sawtooth wave generator SAW is connected to the input of comparator CMP. The output of comparator CMP is connected to the inputs of monostable multivibrator MONO, inverter NOT, and multiplier AND1. The output of inverter NOT is connected to the input of multiplier AND2. The output of monostable multivibrator MONO is connected to the inputs of multipliers AND1 and AND2. The output of multiplier AND1 is connected to the drive signal input of drive circuit DR1, and the output of multiplier AND2 is connected to the drive signal input of drive circuit DR2.

2. The novel input voltage range widening control device as described in claim 1, characterized in that: It also includes a limiter LIM, whose input is connected to the output of a PI regulator PI1, and whose output is connected to the input of a variable frequency sawtooth wave generator SAW.

3. The novel input voltage range widening control device as described in claim 2, characterized in that: The input terminals of error amplifiers EAP1 and EAP2 are also connected to a voltage reference value V. ref1 .

4. The novel control device for widening the input voltage range as described in claim 1, characterized in that: The converter TD is connected to the input voltage V. in .

5. A control method for a novel extended input voltage range control device as described in any one of claims 1-4, characterized in that... Includes the following steps: Step 1: At the start of any cycle, the output terminal of the converter TD outputs a sampled output voltage V. oa The error signal V is amplified by error amplifiers EAP1 and EAP2. e1 With V e2 And input them to the input terminals of PI controller PI1 and PI controller PI2 respectively; Step 2, the error signal V e1 After being regulated by PI regulator PI1, the signal is input to the input terminal of the variable frequency sawtooth wave generator (SAW) to generate a variable frequency sawtooth wave signal V. SAW ; Step 3, convert the error signal V e2 The signal V is generated after the input PI regulator PI2 is adjusted. PI2 ; Step 4, transfer signal V SAW The signal V is input to the positive terminal of comparator CMP. PI2 The input is fed to the negative terminal of comparator CMP. After processing, comparator CMP outputs a signal to the signal input terminal of monostable multivibrator MONO, the input terminal of multiplier AND1, and the input terminal of inverter NOT. Step 5, convert the Q signal V of the monostable multi-oscillator (MONO) to... dead The input is fed into multiplier AND1, which processes the output signal of comparator CMP and the Q signal V of monostable multivibrator MONO. dead The output signal is then sent to the drive circuit DR1, which outputs a drive signal to control the conduction of control switches Q1 and Q4. Step 6, convert the Q-terminal signal V of the monostable multi-oscillator (MONO) to... dead The output signal of the inverter NOT is input to multiplier AND2. Multiplier AND2 processes the output signal of inverter NOT and the Q signal V of monostable multivibrator MONO. dead The output signal is then sent to the drive circuit DR2, which outputs a drive signal to control the conduction of control switches Q2 and Q3.

6. The control method of the novel input voltage range widening control device as described in claim 5, characterized in that: In step 1, when the error amplifier EAP1 performs signal processing, it also receives a voltage reference value V. ref1， Error amplifier EAP1 will sample the output voltage V oa With voltage reference value V ref1 After processing, an amplified error signal V is generated. e1 .

7. The control method of the novel input voltage range widening control device as described in claim 5, characterized in that: In step 1, when the error amplifier EAP2 performs signal processing, it also receives a voltage reference value V. ref1， Error amplifier EAP2 will sample the output voltage V oa With voltage reference value V ref1 After processing, an amplified error signal V is generated. e2 .

8. The control method of the novel extended input voltage range control device as described in claim 5, characterized in that: In step 2, the error signal V e1 After being regulated by PI regulator PI1, the signal is first input to limiter LIM, and then the output signal of limiter LIM is input to the input terminal of variable frequency sawtooth wave generator SAW.

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