Method for wide-range power and gain regulation and efficiency optimization of resonant converter based on hybrid modulation of phase-shift and frequency variation and DC / DC converter

Abstract

The application discloses a resonant converter wide-range power and gain adjustment and efficiency optimization method based on hybrid modulation of out-of-phase and frequency conversion and a DC / DC converter. The method comprises the following steps: constructing a total loss model according to preset converter parameters; obtaining a first total loss curve and a plurality of second total loss curves under a preset input voltage by using the total loss model, obtaining a loss intersection point based on the first total loss curve and the second total loss curve, and setting an out-of-phase angle corresponding to the loss intersection point as an optimal modulation switching angle; collecting a real-time input voltage and a load state to calculate a target out-of-phase angle; when the target out-of-phase angle is smaller than the optimal modulation switching angle, adjusting the size of the target out-of-phase angle based on an out-of-phase modulation mode; and when the target out-of-phase angle reaches the optimal modulation switching angle after adjustment of the out-of-phase modulation mode, adjusting a switching frequency based on a frequency conversion modulation mode. The application can solve the problem of sharp reduction of efficiency of a traditional converter under low-gain light-load demand.

Claims

1. A method for wide-range power and gain regulation and efficiency optimization of a resonant converter based on hybrid modulation of out-of-phase and variable frequency applied to a DC / DC converter, characterized in that, The DC / DC converter includes a dual full-bridge inverter network and a four-way power combiner. The dual full-bridge inverter network includes a first full-bridge inverter unit and a second full-bridge inverter unit. The four-way power combiner includes four resonant branches. The wide-range power and gain adjustment and efficiency optimization method for the resonant converter based on hybrid phase and frequency conversion modulation includes: A total loss model is constructed based on preset converter parameters, wherein the total loss model includes at least the converter's switching transistor conduction loss, switching loss, magnetic component loss, and rectifier loss; The total loss model is used to obtain a first total loss curve and several second total loss curves under a preset input voltage. Based on the first total loss curve and the second total loss curve, the loss crossover point is obtained. The out-of-phase angle corresponding to the loss crossover point is set as the optimal modulation switching angle. The out-of-phase angle is the phase difference between the leading bridge arm and the lagging bridge arm drive signal in the first full-bridge inverter unit and the second full-bridge inverter unit. The system collects real-time input voltage and load status to calculate the target phase angle. When the target phase angle is less than the optimal modulation switching angle, the target phase angle is adjusted based on the phase modulation mode. When the target phase angle reaches the optimal modulation switching angle as the phase modulation mode is adjusted, the switching frequency is adjusted based on the frequency conversion modulation mode. The real-time switching between the phase modulation mode and the frequency conversion modulation mode is used to regulate the DC / DC converter. The control parameters of the four-way power combiner are configured to meet the full-condition soft-switching critical condition. The full-condition soft-switching critical condition is that the fundamental equivalent impedance of the resonant branch is inductive, and the equivalent inductance of the resonant branch and the parasitic capacitance of the switching transistor in the dual full-bridge inverter network satisfy the energy balance equation. The energy balance equation is expressed as follows: wherein, I off is the instantaneous current amplitude at the turn-off time of the switch tube, V bus is the DC input voltage, L eq is the equivalent inductance of the resonance branch, C oss is the parasitic capacitance of the switch tube in the double full-bridge inverter network.

2. The method for wide-range power and gain adjustment and efficiency optimization of resonant converters based on heterogeneous and frequency conversion hybrid modulation according to claim 1, characterized in that, The first total loss curve is the total loss curve under the out-of-phase modulation mode, and the second total loss curve is the total loss curve under the frequency conversion modulation mode with different out-of-phase angles.

3. The method for wide-range power and gain adjustment and efficiency optimization of resonant converters based on heterogeneous and frequency conversion hybrid modulation according to claim 1, characterized in that, The loss crossover point is the intersection point where the total system loss is the lowest and the first total loss curve encloses each of the second total loss curves.

4. The method for wide-range power and gain adjustment and efficiency optimization of resonant converters based on heterogeneous and frequency conversion hybrid modulation according to claim 1, characterized in that, The out-of-phase modulation mode refers to fixing the switching frequency of the DC / DC converter and adjusting the out-of-phase angles of the first full-bridge inverter unit and the second full-bridge inverter unit to change the vector synthesis amplitude of the input voltage of the four-channel power combiner.

5. The method for wide-range power and gain adjustment and efficiency optimization of resonant converters based on heterogeneous and frequency conversion hybrid modulation according to claim 1, characterized in that, The frequency conversion modulation mode refers to fixing the phase angle of the first full-bridge inverter unit and the second full-bridge inverter unit, and adjusting the switching frequency of the DC / DC converter to change the equivalent impedance of the four-channel power combiner.

6. The method for wide-range power and gain adjustment and efficiency optimization of resonant converters based on heterogeneous and frequency conversion hybrid modulation according to claim 1, characterized in that, The output voltage gain of the four-channel power combiner is expressed as follows: in, θ Let G be the phase angle, and G be the output voltage gain. max This represents the maximum gain at the in-phase moment.

7. A DC / DC converter, wherein the DC / DC converter utilizes the wide-range power and gain adjustment and efficiency optimization method for a resonant converter based on hybrid out-of-phase and frequency conversion modulation as described in any one of claims 1 to 6, characterized in that, The DC / DC converter includes: a DC input terminal, a dual full-bridge inverter network, a four-way power combiner, a high-frequency transformer, and a rectifier; One end of the dual full-bridge inverter network is connected to the DC input terminal, the other end of the dual full-bridge inverter network is connected to one end of the four-way power combiner, one end of the high-frequency transformer is connected to the other end of the four-way power combiner, and the other end of the high-frequency transformer is connected to the rectifier. The dual full-bridge inverter network includes a first full-bridge inverter unit and a second full-bridge inverter unit connected in parallel. The first full-bridge inverter unit includes a first leading bridge arm and a first lagging bridge arm, and the second full-bridge inverter unit includes a second leading bridge arm and a second lagging bridge arm. The four-channel power combiner includes a first resonant branch, a second resonant branch, a third resonant branch, and a fourth resonant branch, each of which includes a resonant inductor and a resonant capacitor connected in series.

8. The DC / DC converter according to claim 7, characterized in that, The high-frequency transformer includes a primary winding and a secondary winding. The primary winding is connected to the output of the four-way power combiner and is used to combine the energy of the four branches and perform electrical isolation and voltage conversion. The rectifier is connected to the secondary winding of the high-frequency transformer and is used to convert AC power into DC power and output it.

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