A hybrid control strategy for matrix-boost LLC resonant converter

Abstract

The present invention discloses a hybrid control strategy suitable for a matrix boost LLC resonant converter, which belongs to the field of power electronics technology. The hybrid control strategy is divided into three modes: half voltage, half current and full voltage and current mode. The half voltage mode is to control the output voltage of the matrix transformer T2 to be zero. In this case, only T1 transmits power to the load to achieve half voltage output. The system can operate in this mode in the standby state to reduce the standby power consumption of the system; the half current mode is to control the windings #1 and #4 of the transformers T1 and T2 to work, and turn off the driving signal of the H bridge corresponding to the windings #2 and #3. In this case, only windings #1 and #4 transmit power to the load to achieve half current output. The system can operate in this mode from no-load to half-load state; the full voltage and current mode is to ensure that H (1,1) 、H (1,2) 、H (2,1) 、H (2,2) The driving signal is consistent. In this case, all windings of the matrix transformer transmit power to the load, achieving full voltage and full current output. It can operate in this mode from half load to full load.

Description

Technical Field

[0001] The present invention relates to the field of switching power supply control, and specifically designs a hybrid control strategy suitable for a matrix boost LLC resonant converter. Background Art

[0002] To accommodate high-power airborne power conversion applications, power expansion is required at the topology level. Matrix transformers offer a promising solution. Their greatest advantage is that magnetic coupling between transformer windings enables automatic current sharing between parallel windings, making them ideal for low-voltage, high-current applications. Currently, matrix transformers are primarily used for step-down applications, making existing topologies unsuitable for step-up and high-power applications.

[0003] Currently, the control strategies involving matrix transformer topologies all adopt unified control, that is, the driving signals between the MOS tubes of each parallel winding of the matrix transformer are consistent, so multiple parallel windings can be equivalent to one winding. Summary of the Invention

[0004] The purpose of the present invention is to provide a hybrid control strategy for a matrix boost LLC resonant converter, which distributes the power transmission of parallel windings according to different load sizes to optimize the converter's operating efficiency over the full load range.

[0005] The technical solution of the present invention is: a hybrid control strategy suitable for a matrix-type boost LLC resonant converter, which mainly includes two separate matrix transformers T1 and T2, four full-bridge circuits on the low-voltage side, a resonant network and a voltage-doubling rectifier circuit; transformer T1 includes winding #1, winding #2 and winding #3; transformer T2 includes winding #4, winding #5 and winding #6. The primary windings #1, #2, #4 and #5 of transformers T1 and T2 are connected in parallel, and windings #3 and #6 are connected in series; windings #1, #2, #4 and #5 are on the low-voltage side; windings #3 and #6 are on the high-voltage side; the input Vin is divided into four paths and connected to the four H-bridges of the converter, respectively defined as H (1,1) Bridge, H (1,2) Bridge, H (2,1) Bridge and H (2,2) Bridge, each H bridge is connected in parallel with an input filter capacitor Cin, where H (1,1) The bridge includes MOS tubes Q1_1, Q1_2, Q1_3 and Q1_4; H (1,2) The bridge includes MOS tubes Q2_1, Q2_2, Q2_3 and Q2_4; H (2,1) The bridge includes MOS tubes Q3_1, Q3_2, Q3_3 and Q3_4; H (2,2) The bridge includes MOS tubes Q4_1, Q4_2, Q4_3 and Q4_4; H (1,1) The output of the bridge inverter is connected to winding #1 of transformer T1, H(1,2) The output of the bridge inverter is connected to winding #2 of transformer T1, H (2,1) The output of the bridge inverter is connected to the winding #3 of transformer T2, H (2,2) The output of the bridge inverter is connected to winding #4 of transformer T2; winding #3 of transformer T1 and winding #6 of T2 are connected in series, one end of winding #3 is connected in series with resonant capacitor Cr, and winding #6 is connected to auxiliary inductor Ls. The high-voltage side of the matrix transformer of the converter includes a resonant capacitor Cr and a resonant inductor Lr connected in series, as well as an auxiliary inductor Ls connected in parallel to the input end of the voltage-doubling rectifier bridge; the voltage-doubling rectifier bridge includes a first diode D1, a second diode D2, a first capacitor C1, and a second capacitor C2. D1 and D2 are connected in series to form a diode half-bridge, C1 and C2 are connected in series to form a capacitor half-bridge, and the diode half-bridge and capacitor half-bridge are connected in parallel to form a voltage-doubling rectifier bridge. The output of the voltage-doubling rectifier bridge circuit is connected to the filter capacitor Co and the load Ro.

[0006] The hybrid control strategy for the matrix-type high-boost LLC resonant converter is divided into three modes: half-voltage mode, half-current mode, and full-voltage-current mode:

[0007] The half-voltage mode is achieved by controlling the output winding voltage of the matrix transformer T2 to zero. In this case, only T1 transmits power to the load, achieving half-voltage output. This mode can be used in the standby state to reduce the standby power consumption of the system.

[0008] The half-current mode controls the operation of windings #1 and #4 of transformers T1 and T2, and shuts down the drive signals of the H-bridges corresponding to windings #2 and #3. In this case, only windings #1 and #4 transmit power to the load, achieving half-current output. This mode can be used from no-load to half-load conditions.

[0009] The full voltage and current mode ensures that H (1,1) 、H (1,2) 、H (2,1) 、H (2,2) The driving signals of the matrix transformer are completely consistent. In this case, all windings of the matrix transformer transmit power to the load, achieving full voltage and full current output. It can operate in this mode from half load to full load.

[0010] Compared with the existing full voltage and current mode output control strategy, the hybrid control strategy for the matrix boost LLC resonant converter provided by the present invention has the following advantages:

[0011] 1. The half-voltage mode output control proposed in the present invention reduces the driving loss and switching loss of the entire system because only half of the H-bridge is working in the topology, resulting in lower power consumption of the converter in standby mode.

[0012] 2. The semi-current mode output control proposed in the present invention also reduces the drive loss and switching loss of the converter because only half of the H-bridge in the topology is working, and can improve the operating efficiency in the load range from light load to half load. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 FIG. 1 is a topology diagram of a matrix-type boost LLC resonant converter as a control object in an embodiment.

[0014] Figure 2 The figure shows the topological equivalent schematic diagram under full voltage and current mode output control in this embodiment.

[0015] Figure 3 Shown is a schematic diagram of topological equivalent under semi-current mode output control in an embodiment.

[0016] Figure 4 The figure shows a topological equivalent schematic diagram under half-voltage mode output control in an embodiment. DETAILED DESCRIPTION

[0017] In order to make the purpose and objective of the present invention clearer, the hybrid control strategy applicable to the matrix boost LLC resonant converter will be described in detail below in combination with the technical points and advantages.

[0018] The hybrid control strategy proposed in this invention is for the matrix boost LLC resonant converter topology, see Figure 1The primary side of the matrix transformer of the converter is composed of four full-bridge inverter circuits, which are defined as H(1,1) bridge, H(1,2) bridge, H(2,1) bridge and H(2,2) bridge respectively. The H(1,1) bridge includes a first MOS transistor Q1_1, a second MOS transistor Q1_2, a third MOS transistor Q1_3, and a fourth MOS transistor Q1_4; the H(1,2) bridge includes a first MOS transistor Q2_1, a second MOS transistor Q2_2, a third MOS transistor Q2_3, and a fourth MOS transistor Q2_4; the H(2,1) bridge includes a first MOS transistor Q3_1, a second MOS transistor Q3_2, a third MOS transistor Q3_3, and a fourth MOS transistor Q3_4; and the H(2,2) bridge includes a first MOS transistor Q4_1, a second MOS transistor Q4_2, a third MOS transistor Q4_3, and a fourth MOS transistor Q4_4. Two separate transformers, T1 and T2, each have three windings. Transformer T1 includes winding #1, winding #2, and winding #3; transformer T2 includes winding #4, winding #5, and winding #6. The inputs of the H(1,1) bridge, H(1,2) bridge, H(2,1) bridge, and H(2,2) bridge are connected to the four input voltages Vin and the input filter capacitor Cin, respectively. The inverter output of the H(1,1) bridge is connected to winding #1 of transformer T1, the inverter output of the H(1,2) bridge is connected to winding #2 of transformer T1, the inverter output of the H(2,1) bridge is connected to winding #3 of transformer T2, and the inverter output of the H(2,2) bridge is connected to winding #4 of transformer T2. The primary windings #1, #2, #4, and #5 of transformers T1 and T2 are connected in parallel, while windings #3 and #6 are connected in series. The secondary side of the converter's matrix transformer includes a resonant capacitor Cr and a resonant inductor Lr connected in series, as well as an auxiliary inductor Ls connected in parallel to the input of an uncontrolled rectifier bridge. The rectifier bridge after the auxiliary inductor is a full-bridge configuration. The rectifier bridge includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4. D1 and D3 are connected in series to form a diode half-bridge, while D2 and D4 are connected in series to form a diode half-bridge. The two diode half-bridges are connected in parallel to form a rectifier bridge. The output of the rectifier bridge is connected to a filter capacitor Co and the load.

[0019] See Figure 1The first MOS transistors Q1_1, Q2_1, Q3_1, and Q4_1 of the four H-bridges have the same driving voltage waveform, the second MOS transistors Q1_2, Q2_2, Q3_2, and Q4_2 of the four H-bridges have the same driving voltage waveform, the third MOS transistors Q1_3, Q2_3, Q3_3, and Q4_3 of the four H-bridges have the same driving waveform, and the fourth MOS transistors Q1_4, Q2_4, Q3_4, and Q4_4 of the four H-bridges have the same driving voltage waveform. The driving voltages of the first MOS transistors Q1_1, Q2_1, Q3_1, and Q4_1 of the four H-bridges and the second MOS transistors Q1_2, Q2_2, Q3_2, and Q4_2 of the four H-bridges are mutually opposite, with a fixed dead time. The driving voltages of the third MOS transistors Q1_3, Q2_3, Q3_3, and Q4_3 of the four H-bridges and the fourth MOS transistors Q1_4, Q2_4, Q3_4, and Q4_4 of the four H-bridges are mutually opposite, with a fixed dead time. This driving mode can achieve full voltage and current mode output control. The topology under this mode control can be simplified to Figure 2 The circuit shown.

[0020] See Figure 1 , the driving voltage waveforms of the first MOS transistor Q1_1 of the H(1,1) bridge and the first MOS transistor Q3_1 of the H(2,1) bridge are set to be the same; the driving voltage waveforms of the second MOS transistor Q1_2 of the H(1,1) bridge and the second MOS transistor Q3_2 of the H(2,1) bridge are set to be the same; the driving voltage waveforms of the third MOS transistor Q1_3 of the H(1,1) bridge and the third MOS transistor Q3_3 of the H(2,1) bridge are set to be the same; and the driving voltage waveforms of the fourth MOS transistor Q1_4 of the H(1,1) bridge and the fourth MOS transistor Q3_4 of the H(2,1) bridge are set to be the same. The driving voltages of the first MOS transistor Q1_1 of the H(1,1) bridge and the second MOS transistor Q1_2 of the H(1,1) bridge are mutually opposite, with a fixed dead time. The driving voltages of the third MOS transistor Q1_3 of the H(1,1) bridge and the fourth MOS transistor Q1_4 of the H(1,1) bridge are mutually opposite, with a fixed dead time. The driving voltages of the first MOS transistor Q3_1 of the H(2,1) bridge and the second MOS transistor Q3_2 of the H(2,1) bridge are mutually opposite, with a fixed dead time. The driving voltages of the third MOS transistor Q3_3 of the H(2,1) bridge and the fourth MOS transistor Q3_4 of the H(2,1) bridge are mutually opposite, with a fixed dead time. The driving voltages of the four MOS transistors Q2_1, Q2_2, Q2_3, and Q2_4 of the H(1,2) bridge and the four MOS transistors Q4_1, Q4_2, Q4_3, and Q4_4 of the H(2,2) bridge are low. This driving mode can achieve semi-current mode output control. The topology under this mode control can be simplified to Figure 3 The circuit shown.

[0021] See Figure 1, the driving voltage waveforms of the first MOS transistor Q1_1 of the H(1,1) bridge and the first MOS transistor Q2_1 of the H(1,2) bridge are the same; the driving voltage waveforms of the second MOS transistor Q1_2 of the H(1,1) bridge and the second MOS transistor Q2_2 of the H(1,2) bridge are the same; the driving voltage waveforms of the third MOS transistor Q1_3 of the H(1,1) bridge and the third MOS transistor Q2_3 of the H(1,2) bridge are the same; and the driving voltage waveforms of the fourth MOS transistor Q1_4 of the H(1,1) bridge and the fourth MOS transistor Q2_4 of the H(1,2) bridge are the same. The driving voltages of the first MOS transistor Q1_1 of the H(1,1) bridge and the second MOS transistor Q1_2 of the H(1,1) bridge are mutually opposite, and a fixed dead time exists. The driving voltages of the third MOS transistor Q1_3 of the H(1,1) bridge and the fourth MOS transistor Q1_4 of the H(1,1) bridge are mutually opposite, and a fixed dead time exists. The driving voltages of the first MOS transistor Q2_1 of the H(1,2) bridge and the second MOS transistor Q2_2 of the H(1,2) bridge are mutually opposite, and a fixed dead time exists. The driving voltages of the third MOS transistor Q2_3 of the H(1,2) bridge and the fourth MOS transistor Q2_4 of the H(1,2) bridge are mutually opposite, and a fixed dead time exists. The driving voltages of the first MOS transistor Q3_1 of the H(2,1) bridge, the second MOS transistor Q3_2 of the H(2,1) bridge, the first MOS transistor Q4_1 of the H(2,2) bridge, and the second MOS transistor Q4_2 of the H(2,2) bridge are low; the driving voltages of the third MOS transistor Q3_3 of the H(2,1) bridge, the fourth MOS transistor Q3_4 of the H(2,1) bridge, the third MOS transistor Q4_3 of the H(2,2) bridge, and the fourth MOS transistor Q4_4 of the H(2,2) bridge are high. This driving mode enables half-voltage mode output control. The topology under this control mode can be simplified to: Figure 4 The circuit shown.

[0022] See Figure 2 In the first half of the cycle, the current flow path on the primary side of the matrix transformer is: MOS transistor Q1 → primary winding of transformer T → Q4; the current flow path on the secondary side of the matrix transformer is: secondary winding of transformer T → resonant capacitor Cr → resonant inductor Lr → first diode D1 → load → fourth diode D4. In the second half of the cycle, the current flow path on the primary side of the matrix transformer is: MOS transistor Q2 → primary winding of transformer T → Q3; the current flow path on the secondary side of the matrix transformer is: secondary winding of transformer T → second diode D2 → load → third diode D3 → resonant inductor Lr → resonant capacitor Cr.

[0023] See Figure 3In the first half of the cycle, the current flow path on the primary side of the matrix transformer is: MOS transistor Q1_1 → transformer T1's winding #1 → Q1_4, MOS transistor Q3_1 → transformer T2's winding #4 → Q3_4. The current flow path on the secondary side of the matrix transformer is: transformer T1's winding #3 → resonant capacitor Cr → resonant inductor Lr → first diode D1 → load → fourth diode D4 → transformer T2's winding #6. In the second half of the cycle, the current flow path on the primary side of the matrix transformer is: MOS transistor Q1_2 → transformer T1's winding #1 → Q1_3, MOS transistor Q3_2 → transformer T2's winding #4 → Q3_3. The current flow path on the secondary side of the matrix transformer is: transformer T2's winding #6 → second diode D2 → load → third diode D3 → resonant inductor Lr → resonant capacitor Cr → transformer T1's winding #3.

[0024] See Figure 4 In the first half of the cycle, the current flow path on the primary side of the matrix transformer is: MOS transistor Q1_1 → transformer T1's winding #1 → Q1_4, MOS transistor Q2_1 → transformer T1's winding #2 → Q2_4. The current flow path on the secondary side of the matrix transformer is: transformer T1's winding #3 → resonant capacitor Cr → resonant inductor Lr → first diode D1 → load → fourth diode D4. In the second half of the cycle, the current flow path on the primary side of the matrix transformer is: MOS transistor Q1_2 → transformer T1's winding #1 → Q1_3, MOS transistor Q2_2 → transformer T1's winding #2 → Q2_3. The current flow path on the secondary side of the matrix transformer is: transformer T1's winding #3 → second diode D2 → load → third diode D3 → resonant inductor Lr → resonant capacitor Cr.

[0025] Although the above description has described in detail the hybrid control strategy applicable to the matrix boost LLC resonant converter, it is not limited to the above example. Considering the topology of the converter, there are also other options such as setting H (1,2) 、H (2,2) Transfer power to the load; set H (2,1) 、H (2,2) Drive setting methods such as transmitting power to the load can also achieve half-voltage, half-current mode output, and these replacements for the present invention also fall within the scope of protection of the present invention.

Claims

1. A hybrid control method for a matrix boost LLC resonant converter, characterized in that: The resonant converter mainly includes two separate matrix transformers T1 and T2, four full-bridge circuits on the low-voltage side, a resonant network and a voltage-doubling rectifier circuit; The transformer T1 includes winding #1, winding #2, and winding #3, and the transformer T2 includes winding #4, winding #5, and winding #6. The primary windings #1, #2, #4, and #5 of the transformers T1 and T2 are connected in parallel, and windings #3 and #6 are connected in series. Windings #1, #2, #4, and #5 are on the low-voltage side, and windings #3 and #6 are on the high-voltage side. The input Vin is divided into four paths and connected to the four H-bridges of the converter, which are defined as H (1,1) bridge, H (1,2) bridge, H (2,1) bridge and H (2,2) bridge respectively. Each H-bridge is connected in parallel with the input filter capacitor Cin. The H (1,1) bridge includes MOS transistors Q1_1, Q1_2, Q1_3 and Q1_4; the H (1,2) bridge includes MOS transistors Q2_1, Q2_2, Q2_3 and Q2_4; the H (2,1) bridge includes MOS transistors Q3_1, Q3_2, Q3_3 and Q3_4; the H (2,2) bridge includes MOS transistors Q4_1, Q4_2, Q4_3 and Q4_4; The H (1,1) bridge inverter output is connected to winding #1 of transformer T1, the H (1,2) bridge inverter output is connected to winding #2 of transformer T1, the H (2,1) bridge inverter output is connected to winding #3 of transformer T2, and the H (2,2) bridge inverter output is connected to winding #4 of transformer T2; The hybrid control method is divided into three modes: half voltage mode, half current mode and full voltage and current mode: The half-voltage mode is achieved by controlling the output winding voltage of the matrix transformer T2 to zero. In this case, only the matrix transformer T1 transmits power to the load, achieving half-voltage output. The half-current mode is when winding #1 and winding #4 of the matrix transformers T1 and T2 are operating, and the drive signals of the H-bridges corresponding to windings #2 and #3 are turned off. In this case, only windings #1 and #4 transmit power to the load, achieving half-current output. The full voltage and current mode ensures that the driving signals of the H (1,1) bridge, H (1,2) bridge, H (2,1) bridge, and H (2,2) bridge are completely consistent. In this case, all windings of the matrix transformer transmit power to the load to achieve full voltage and full current output.

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