Novel control device and method for widening input voltage range

Abstract

The invention discloses a novel control device and method for widening an input voltage range, and the device comprises a converter TD, an error amplifier EAP1, an error amplifier EAP2, an error amplifier EAP2, a PI regulator PI1, a PI regulator PI2, a frequency conversion sawtooth wave generator SAW, a comparator CMP, a phase inverter NOT, a multiplier AND1, a multiplier AND2, a drive circuit DR1, a drive circuit DR2, and a monostable multi-oscillation generator MONO. According to the control method, the output voltage is adjusted by simultaneously adjusting the working frequency and the duty ratio. Through the implementation of the dual-output LLC resonant converter, the input voltage range of the dual-output LLC resonant converter is widened, the working frequency and the duty ratio can be changed at the same time during working, and after the input voltage jumps or the output branch load jumps, the working frequency of the control mode is closer to the resonant frequency compared with the working frequency of frequency conversion control.

Description

Technical Field

[0001] The present invention relates to the technical field of data switch converters, and in particular to a novel control device and method for widening the input voltage range. Background Art

[0002] As the source of power for electronic devices, power supplies play an important role in power conversion. With the increasing requirements for high efficiency and low electromagnetic interference (EMI), dual-output LLC resonant converters have gradually become a hot spot in the development of power supply technology. As a new soft switching technology, dual-output LLC resonant converters have the advantages of low EMI, zero voltage switch-on (ZVS) of the switch tube, and zero voltage shutdown (ZCS) of the rectifier diode, and are widely used in the power supply industry. The main control method of the dual-output LLC resonant converter is usually frequency control, but under this control method, its input voltage range is narrow. Under light load conditions, the operating frequency deviates from the resonant frequency a lot, resulting in the system being unable to achieve high-efficiency operation. Summary of the invention

[0003] In order to solve the above technical problems, the present invention proposes a new control method and device for widening the input voltage range. The control method adjusts the output voltage by adjusting the operating frequency and duty cycle at the same time, realizes a wide range of output, and has a high engineering application value. At the same time, the control method is not only used in dual-output LLC resonant converters, but also can be applied to LLC resonant converters.

[0004] The present invention is achieved through the following technical solutions.

[0005] The present invention provides a novel control device for widening the input voltage range, comprising a converter 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 multi-oscillation generator MONO; the converter TD is a dual-output full-bridge LLC resonant converter, provided with control switch tubes Q1~Q4, the output end of the drive circuit DR1 is connected to the control switch tubes Q1 and Q4 to control the conduction of the control switch tubes Q1 and Q4, the output end of the drive circuit DR2 is connected to the control switch tubes Q2 and Q3 to control the conduction of the control switch tubes Q2 and Q3; the output end of the converter TD is connected to the input end of the error amplifier EAP1 and the error amplifier EAP2, the error amplifier EAP1 is connected to the input end of the error amplifier EAP2, and the error amplifier EAP2 is connected to the input end of the error amplifier EAP1. The output end of P1 is connected to the input end of the PI regulator PI1, and the output end of the PI regulator PI1 is connected to 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 to the input end of the comparator CMP; the input end of the error amplifier EAP2 is connected to the input end of the PI regulator PI2, and the output end of the PI regulator PI2 is connected to the input end of the comparator CMP; the output end of the comparator CMP is connected to the input end of the monostable multi-oscillation 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 to the input end of the multiplier AND2, the output end of the monostable multi-oscillation generator MONO is connected to the input ends of the multiplier AND1 and the multiplier AND2, the output end of the multiplier AND1 is connected to the drive signal input end of the drive circuit DR1, and the output end of the multiplier AND2 is connected to the drive signal input end of the drive circuit DR2.

[0006] Furthermore, it also includes a limiter LIM, wherein the input end of the limiter LIM is connected to the output end of the PI regulator PI1, and the output end of the limiter LIM is connected to the input end of the variable frequency sawtooth wave generator SAW.

[0007] Furthermore, the input terminals of the error amplifier EAP1 and the error amplifier EAP2 are also connected to a voltage reference value V ref1 .

[0008] Furthermore, the converter TD is connected to the input voltage V in .

[0009] A novel control method for a control device for widening an input voltage range comprises 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 amplifier EAP1 and the error amplifier EAP2 generate an amplified error signal V e1 With V e2 , and are input to the input terminals of PI regulator PI1 and PI regulator PI2 respectively; Step 2: The error signal V e1 After being adjusted by the PI regulator PI1, the signal is input to the input end of the variable frequency sawtooth wave generator SAW to generate a variable frequency sawtooth wave signal V SAW ; and the frequency conversion sawtooth wave signal V SAW enter; Step 3: convert the error signal V e2 The input PI regulator PI2 generates a signal V PI2 ; Step 4: Set the signal V SAW Input to the positive terminal of the comparator CMP, the signal V PI2 The signal is input to the negative terminal of the comparator CMP, and after being processed, the comparator CMP outputs a signal to the signal input terminal of the monostable multi-oscillation generator MONO, the input terminal of the multiplier AND1, and the input terminal of the inverter NOT; Step 5: The Q-terminal signal V dead Input to multiplier AND1, multiplier AND1 processes the output signal of comparator CMP and the Q-end signal V of monostable multi-oscillator MONO dead Then, the output signal is sent to the driving circuit DR1, and the driving circuit DR1 outputs the driving signal to control the conduction of the switch tubes Q1 and Q4; Step 6: The Q-terminal signal V dead Input to multiplier AND2, input the output signal of inverter NOT to multiplier AND2, multiplier AND2 processes the output signal of inverter NOT and the Q-end signal V of monostable multi-oscillator MONO dead Then the output signal is sent to the driving circuit DR2, and the driving circuit DR2 outputs the driving signal to control the conduction of the switch tubes Q2 and Q3.

[0010] Furthermore, in step 1, when the error amplifier EAP1 performs signal processing, a voltage reference value V is also input. ref1， The error amplifier EAP1 samples the output voltage V oa With the voltage reference value V ref1 After processing, an amplified error signal V is generated. e1 .

[0011] Furthermore, in step 1, when the error amplifier EAP2 performs signal processing, a voltage reference value V is also input.ref1， The error amplifier EAP2 samples the output voltage V oa With the voltage reference value V ref1 After processing, an amplified error signal V is generated. e2 .

[0012] Furthermore, in step 2, the error signal V e1 After being adjusted by the PI regulator PI1, the signal is first input into the limiter LIM, and then the output signal of the limiter LIM is input into the input end of the variable frequency sawtooth wave generator SAW.

[0013] The beneficial effects of the present invention are: (1) the input voltage range of the dual-output LLC resonant converter is widened; (2) the operating frequency and duty cycle can be changed simultaneously; (3) after the input voltage jumps or the output branch load jumps, the operating frequency of the new control method is closer to the resonant frequency than the operating frequency of the variable frequency control. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a system structure diagram of the present invention; Figure 2 It is a circuit structure block diagram when the present invention adopts a dual-output LLC resonant converter; Figure 3 It is a waveform diagram of the output voltage, resonant inductance, excitation inductance and control pulse of the switch device of the output branch 1 when the dual-output LLC resonant converter is adopted in the present invention; Figure 4 is a control timing diagram of the control device of the present invention; Figure 5 This is the output voltage waveform of the traditional variable frequency controlled dual output LLC resonant converter when the input voltage jumps from 400V to 300V; Figure 6 This is the output voltage waveform of the traditional variable frequency controlled dual output LLC resonant converter when the input voltage jumps from 400V to 250V; Figure 7 This is the output voltage waveform of the present invention when the input voltage jumps from 400V to 250V. DETAILED DESCRIPTION

[0015] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0016] like Figure 1 As shown, a specific embodiment of the present invention is: a novel control method and device for a dual-output LLC resonant converter with widened input voltage control, which is composed of a converter TD and a control device for switches Q1, Q2, Q3, and Q4. The sampled output voltage V oaConnect the error amplifier EAP1, PI regulator PI1, limiter LIM, variable frequency sawtooth wave generator SAW, comparator CMP, EAP1 and the reference voltage V ref1 ; Sample output voltage V oa Connect the error amplifier EAP2, PI regulator PI2, comparator CMP, EAP2 and the reference voltage V ref1 The output end of CMP is connected to the monostable multi-oscillator MONO, multiplier AND1 and multiplier AND2 in sequence, driving DR1 and driving DR2, where AND1 is also connected to the Q end of TGR, and AND2 is also connected to a Q end signal of TGR through a NOT gate NOT; V oa , DR1, and DR2 are respectively connected to the dual-output LLC resonant converter.

[0017] The converter TD in this example is a dual-output LLC resonant converter, and its working process and principle are as follows.

[0018] The working process and principle of the control device using variable frequency and variable duty cycle control: like Figure 2 As shown, at the beginning of any cycle, the output voltage V oa and voltage reference value V ref1 The error amplifier EAP1 generates an amplified error signal V e1 , V e1 The signal adjusted by the PI1 regulator is limited by the limiter LIM and then input into the sawtooth wave generator SAW to generate a sawtooth wave signal V that can change the frequency. SAW , V SAW Input to the positive terminal of the comparator CMP; output voltage V oa and voltage reference value V ref1 The error amplifier EAP2 generates an amplified error signal V e2 , V e2 The output signal V after being adjusted by the PI2 regulator PI2 Input to the negative terminal of the comparator CMP; the output signal of CMP is input to the signal input terminal of the monostable multi-oscillation generator MONO. The signal V dead Input to multiplier AND1, CMP output signal input to multiplier AND1, V dead The signal multiplied by the CMP output signal is input to the drive circuit DR1 to control the conduction of the switch tubes Q1 and Q4. The signal V dead Input to multiplier AND2, CMP output signal is input to multiplier AND2 through an inverter NOT, V deadThe signal obtained by multiplying the CMP output signal by the signal of the inverter is input into the driving circuit DR2 to control the conduction of the switch tubes Q2 and Q3.

[0019] Figure 3 The output voltage waveform of the LLC resonant converter with dual outputs is shown in Figure 1. Figure 3 In T on During this time, the switch tubes Q1 and Q4 are turned on, Q2 and Q3 are turned off, and the current I flowing through the resonant inductor Lr and the current I flowing through the magnetizing inductor Lm No resonance occurs, and the energy flows to the secondary side of the transformer, and the output voltage V oa Rise, in T off During this time, the switch tubes Q2 and Q3 are turned on, Q1 and Q4 are turned off, and the current I flowing through the resonant inductor Lr and the current I flowing through the magnetizing inductor Lm No resonance occurs at the beginning, and the energy flows to the secondary side of the transformer, and the output voltage V oa Rising, when the energy is transmitted for a period of time, I Lr and I Lm Resonance occurs, at this time V oa Start to descend.

[0020] Figure 4 The control timing diagram of the control device is shown. Figure 4 At the beginning of each switching cycle, the variable frequency sawtooth wave generator SAW generates a variable frequency sawtooth wave signal V SAW , sample output voltage V oa With reference voltage V ref1 The error signal V generated by the error amplifier e2 After passing through the regulator PI2, the signal V PI2 , V SAW and V PI2 Through the comparison of comparator CMP, when V SAW Less than V PI2 When a high-level signal is obtained, CMP inputs the obtained high-level signal into the driving circuit to turn on the switch tubes Q1 and Q4, and turn off Q2 and Q3. At this time, the output voltage V oa starts to rise; when V SAW Greater than V PI2 When a low-level signal is obtained, CMP inputs the obtained low-level signal into the driving circuit to turn on the switch tubes Q2 and Q3, and turn off Q1 and Q4. At this time, the output voltage V oa After rising for a while, it starts to fall. When the input voltage changes, the SAW generates a signal V SAW The frequency and V PI2The amplitude of changes at the same time, causing the operating frequency and duty cycle of the converter to change at the same time, thereby controlling the output voltage to achieve stability.

[0021] The method of the present invention was simulated and analyzed in the time domain using PSIM simulation software, and the results are as follows.

[0022] Figure 5-Figure 7 The present invention is implemented in a dual-output LLC resonant converter with variable frequency control and input voltage V in Time domain simulation waveform of the output voltage when it changes, Figure 5 , Figure 6 The output voltage time domain simulation waveforms when the input voltage jumps from 400V to 300V and the input voltage jumps from 400V to 250V under variable frequency control are shown respectively; Figure 7 Shown is a time domain simulation waveform diagram of the output voltage when the input voltage jumps from 400V to 250V under the control of the present invention. Figure 5 In the variable frequency control dual output LLC resonant converter, the input voltage V in After jumping 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 variable frequency control dual output LLC resonant converter, the input voltage V in After jumping from 400V to 250V, the output voltage cannot reach a new stable state; Figure 7 In this control, the input voltage V in After jumping 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 condition is that the input voltage V in =400V, voltage reference value V ref1 =420V, V ref2 =24V, resonant inductor L r =12μH, excitation inductance L m =54μH, resonant capacitor 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 input voltage range, characterized in that: It includes a converter 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 multi-oscillation generator MONO; The converter TD is a full-bridge LLC resonant converter, and is provided with control switch tubes Q1 to Q4. The output end of the drive circuit DR1 is connected to the control switch tubes Q1 and Q4 to control the conduction of the control switch tubes Q1 and Q4. The output end of the drive circuit DR2 is connected to the control switch tubes Q2 and Q3 to control the conduction of the control switch tubes Q2 and Q3. The output end of the converter TD is connected to the input ends of the error amplifier EAP1 and the error amplifier EAP2, the output end of the error amplifier EAP1 is connected to the input end of the PI regulator PI1, the output end of the PI regulator PI1 is connected to 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 to the input end of the comparator CMP; the input end of the error amplifier EAP2 is connected to the input end of the PI regulator PI2, and the output end of the PI regulator PI2 is connected to the input end of the comparator CMP; the output end of the comparator CMP is connected to the input end of the monostable multi-oscillation 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 to the input end of the multiplier AND2, the output end of the monostable multi-oscillation generator MONO is connected to the input ends of the multipliers AND1 and AND2, the output end of the multiplier AND1 is connected to the drive signal input end of the drive circuit DR1, and the output end of the multiplier AND2 is connected to the drive signal input end of the drive circuit DR2.

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

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

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

5. A novel control method for widening the input voltage range control device, characterized in that The following steps are involved: Step 1: At the start of any cycle, the output terminal of the converter TD outputs a sampled output voltage V oa , the error amplifier EAP1 and the error amplifier EAP2 generate an amplified error signal V e1 With V e2 , and are input to the input terminals of PI regulator PI1 and PI regulator PI2 respectively; Step 2: The error signal V e1 After being adjusted by the PI regulator PI1, the signal is input to the input end of the variable frequency sawtooth wave generator SAW to generate a variable frequency sawtooth wave signal V SAW ; and the frequency conversion sawtooth wave signal V SAW enter; Step 3: convert the error signal V e2 The input PI regulator PI2 generates a signal V PI2 ; Step 4: Set the signal V SAW Input to the positive terminal of the comparator CMP, the signal V PI2 The signal is input to the negative terminal of the comparator CMP, and after being processed, the comparator CMP outputs a signal to the signal input terminal of the monostable multi-oscillation generator MONO, the input terminal of the multiplier AND1, and the input terminal of the inverter NOT; Step 5: The Q-terminal signal V dead Input to multiplier AND1, multiplier AND1 processes the output signal of comparator CMP and the Q-end signal V of monostable multi-oscillator MONO dead Then, the output signal is sent to the driving circuit DR1, and the driving circuit DR1 outputs the driving signal to control the conduction of the switch tubes Q1 and Q4; Step 6: The Q-terminal signal V dead Input to multiplier AND2, input the output signal of inverter NOT to multiplier AND2, multiplier AND2 processes the output signal of inverter NOT and the Q-end signal V of monostable multi-oscillator MONO dead Then the output signal is sent to the driving circuit DR2, and the driving circuit DR2 outputs the driving signal to control the conduction of the switch tubes Q2 and Q3.

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

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

8. The novel control device and method for widening the input voltage range as claimed in claim 1, characterized in that: In step 2, the error signal V e1 After being adjusted by the PI regulator PI1, the signal is first input into the limiter LIM, and then the output signal of the limiter LIM is input into the input end of the variable frequency sawtooth wave generator SAW.

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