A non-isolated dual active bridge circuit and common mode voltage suppression method

Abstract

The application discloses a non-isolated dual active bridge circuit and a common-mode voltage suppression method, and realizes the non-isolated dual active bridge circuit, eliminates the limitation of a high-frequency transformer in an isolated dual active bridge circuit, can be applied to scenes of cost and volume sensitivity, high dynamic response speed requirement and possible unbalanced saturation current, and according to the topological characteristics, the application arranges a reactor between half-bridge circuits of two side switch tubes in a single column or a separate column, and in combination with control of a duty cycle of the switch tube, can reduce or eliminate the common-mode voltage between non-two-side capacitors, reduce the insulation design requirement in electrical isolation, and is beneficial to anti-interference design.

Description

TECHNICAL FIELD

[0001] The application relates to a non-isolated dual active bridge circuit and a common-mode voltage suppression method, and belongs to the technical field of power electronics. BACKGROUND

[0002] The isolated dual active bridge has been widely applied in various application occasions such as power electronic transformers and direct-current transformers, and various topological structure variants have been derived, for example, a three-level dual active bridge, an asymmetric dual active bridge and the like. However, the isolated dual active bridge needs a high-frequency transformer for isolation. The high-frequency transformer is difficult to manufacture, is subject to the current process and material level, is difficult to improve capacity and efficiency, and has high cost and large volume. Various optimization control strategies have been derived in the control strategy, for example, a dual-phase shift control or a triple-phase shift control for reducing backflow power. However, because of the existence of the high-frequency transformer, it is necessary to ensure that the control is symmetrical in the positive and negative half cycles, otherwise the transformer will be saturated.

[0003] However, in some occasions where isolation is not required, if the dual active bridge circuit is still designed according to the isolated type, it will be subject to the limitation of the high-frequency transformer, which is not conducive to the optimized design of the system and the advantages of the circuit. Therefore, it is urgent to design a non-isolated dual active bridge circuit. SUMMARY

[0004] The application provides a non-isolated dual active bridge circuit and a common-mode voltage suppression method, which solves the problems disclosed in the background art.

[0005] In order to solve the above technical problems, the technical scheme adopted by the application is as follows:

[0006] A non-isolated dual active bridge circuit comprises a first side parallel circuit and a second side parallel circuit.

[0007] The first side parallel circuit comprises a first capacitor series circuit and a first switch tube half-bridge circuit in parallel, the first capacitor series circuit comprises capacitors C H1 and C H2 in series; the second side parallel circuit comprises a second capacitor series circuit and a second switch tube half-bridge circuit in parallel, the second capacitor series circuit comprises capacitors C L1 and C L2 in series.

[0008] The midpoint A of the first switch tube half-bridge circuit and the midpoint a of the second switch tube half-bridge circuit are connected through a reactor L1, the midpoint B of the first capacitor series circuit and the midpoint b of the second capacitor series circuit are connected, and the ground potential G1 of the first side parallel circuit and the ground potential G2 of the second side parallel circuit are connected through a clamping resistor R C .

[0009] The first switch tube half-bridge circuit comprises switch tubes S1 and S2 connected in series, and the second switch tube half-bridge circuit comprises switch tubes Q1 and Q2 connected in series. H2 The connection of the switch tubes S1 and S2 is a ground potential G1, and the connection of the switch tubes Q1 and Q2 is a ground potential G2. L2 The connection of the switch tubes S1 and S2 is a ground potential G1, and the connection of the switch tubes Q1 and Q2 is a ground potential G2.

[0010] The method comprises: sending control signals to all switch tubes, so that the duty cycles of the switch tubes S1 and S2 are complementary, the duty cycles of the switch tubes Q1 and Q2 are complementary, and the duty cycles of the switch tubes S1 and Q1 are consistent, thereby suppressing the common-mode voltage of the non-isolated dual active bridge circuit.

[0011] The ground potential G1 and the ground potential G2 are not equal at the initial time of the non-isolated dual active bridge circuit.

[0012] The non-isolated dual active bridge circuit comprises a first side parallel circuit and a second side parallel circuit.

[0013] The first side parallel circuit comprises a first capacitor C H , a first switch tube half-bridge circuit and a second switch tube half-bridge circuit connected in parallel, and the second side parallel circuit comprises a second capacitor C L , a third switch tube half-bridge circuit and a fourth switch tube half-bridge circuit connected in parallel.

[0014] The midpoint A of the first switch tube half-bridge circuit and the midpoint a of the third switch tube half-bridge circuit are connected through an inductor L1, the midpoint B of the second switch tube half-bridge circuit and the midpoint b of the fourth switch tube half-bridge circuit are connected through an inductor L2, and the ground potential G1 of the first side parallel circuit and the ground potential G2 of the second side parallel circuit are connected through a clamping resistor R C .

[0015] The first switch tube half-bridge circuit comprises switch tubes S1 and S2 connected in series, the second switch tube half-bridge circuit comprises switch tubes S3 and S4 connected in series, the third switch tube half-bridge circuit comprises switch tubes Q1 and Q2 connected in series, and the fourth switch tube half-bridge circuit comprises switch tubes Q3 and Q4 connected in series. H The connection of the switch tubes S1 and S2 is a ground potential G1, and the connection of the switch tubes Q1 and Q2 is a ground potential G2. L The connection of the switch tubes S1 and S2 is a ground potential G1, and the connection of the switch tubes Q1 and Q2 is a ground potential G2.

[0016] The impedances of the inductors L1 and L2 are equal.

[0017] The method for suppressing common-mode voltage of a non-isolated dual active bridge circuit comprises: sending control signals to all switch tubes, so that the duty cycles of switch tube S1 and switch tube S2 are complementary, the duty cycles of switch tube S3 and switch tube S4 are complementary, the duty cycles of switch tube S1 and switch tube S4 are consistent, the duty cycles of switch tube Q1 and switch tube Q2 are complementary, the duty cycles of switch tube Q3 and switch tube Q4 are complementary, the duty cycles of switch tube Q1 and switch tube Q4 are consistent, and the duty cycles of switch tube S1 and switch tube Q1 are consistent, thereby suppressing the common-mode voltage of the non-isolated dual active bridge circuit.

[0018] The application achieves the following beneficial effects: the application implements a non-isolated dual active bridge circuit, eliminates the limitations of a high-frequency transformer in an isolated dual active bridge circuit, can be applied in scenarios that are sensitive to cost and volume, require high dynamic response speed, and may have unbalanced saturation current, and the application arranges a reactor between the two-side switch tube half-bridge circuits, in combination with control of the duty cycles of the switch tubes, can reduce or eliminate the common-mode voltage between the two-side capacitors, reduce the insulation design requirements in electrical isolation, and is conducive to anti-interference design. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The application relates to a single-phase half-bridge non-isolated dual active bridge circuit topology structure.

[0020] Figure 2 The application relates to common-mode interference between two-side capacitor grounds of a single-phase full-bridge non-isolated dual active bridge circuit.

[0021] Figure 3 The application relates to a two-phase full-bridge non-isolated dual active bridge circuit topology structure.

[0022] Figure 4 The application relates to common-mode interference between two-side capacitor grounds of a two-phase full-bridge non-isolated dual active bridge circuit. DETAILED DESCRIPTION

[0023] The application will be further described below in combination with the drawings. The following examples are only used to more clearly illustrate the technical solutions of the application, and cannot be used to limit the protection scope of the application.

[0024] As shown in Figure 1 , a non-isolated dual active bridge circuit, in particular a single-phase half-bridge non-isolated dual active bridge circuit, comprises a first-side parallel circuit and a second-side parallel circuit.

[0025] The first-side parallel circuit comprises a first capacitor series circuit and a first switch tube half-bridge circuit in parallel. H1 The first capacitor series circuit comprises capacitors C H2 and C H1 The first switch tube half-bridge circuit comprises switch tubes S1 and S2 in series. H2The connection point between them is the midpoint B of the first capacitor series circuit, and the connection point between switching transistors S1 and S2 is the midpoint A of the first switching transistor half-bridge circuit. Capacitor C... H2 The connection point between the transistor S2 and the ground potential G1 is at the ground potential.

[0026] The second parallel circuit includes a second capacitor series circuit and a second switching transistor half-bridge circuit connected in parallel. The second capacitor series circuit includes a capacitor C connected in series. L1 and capacitor C L2 The second switching half-bridge circuit includes switching transistors Q1 and Q2 connected in series. Capacitor C L1 and capacitor C L2 The connection point between them is the midpoint b of the second capacitor series circuit, and the connection point between switching transistors Q1 and Q2 is the midpoint a of the second switching transistor half-bridge circuit. Capacitor C... L2 The connection point with the switching transistor Q2 is at ground potential G2.

[0027] The midpoint A of the first switching half-bridge circuit and the midpoint a of the second switching half-bridge circuit are connected by a reactor L1, i.e., the reactors are arranged in a single row. The midpoint B of the first capacitor series circuit and the midpoint b of the second capacitor series circuit are connected. The ground potential G1 of the first parallel circuit and the ground potential G2 of the second parallel circuit are connected by a clamping resistor R. C connect.

[0028] In the above circuit, a common-mode voltage exists between the capacitors on both sides. It is necessary to reduce or eliminate the common-mode voltage through an inductor and a corresponding suppression method. In one embodiment of the present invention, based on the above circuit, a common-mode voltage suppression method is also disclosed, which includes: sending control signals to all switching transistors to make the duty cycles of switching transistors S1 and S2 complementary, the duty cycles of switching transistors Q1 and Q2 complementary, and the duty cycles of switching transistors S1 and Q1 consistent, thereby suppressing the common-mode voltage of the non-isolated dual active bridge circuit.

[0029] Specifically as follows:

[0030] 1) In the initial state, the capacitance C H1 and capacitor C H2 The voltage of all is V C (V C (Not equal to 0), Capacitor C L1 and capacitor C L2 The voltage is zero, so the potentials at points B and b are the same, but the ground potentials G1 and G2 are not equal; through the configured clamping resistor R C This makes capacitor C H2 Capacitor C L2 and clamping resistor R C A circuit is formed, and the capacitance C H2 Give capacitor C L2Charging, until both voltage is consistent, at this time the ground potential G1 and the ground potential G2 is equal (i.e. potential is equal).

[0031] 2) When all the switch tubes are normal, the duty cycle of switch tube S1 and switch tube S2 is complementary, the duty cycle of switch tube Q1 and switch tube Q2 is complementary, the duty cycle of switch tube S1 and switch tube Q1 is consistent, the power control of the two parallel circuits is realized through the phase shift angle between switch tube S1 and switch tube Q1, which can make the voltage on capacitor C H2 And capacitor C L2 The potential difference between ground potential G1 and ground potential G2 is reduced to a minimum, as shown in Figure 2 .

[0032] In the above circuit, by controlling the duty cycle of switch tube Q1 and switch tube S1, the voltage balancing effect of capacitor C H1 And capacitor C H2 , capacitor C L1 And capacitor C L2 Is consistent, the phase shift angle between switch tube S1 and switch tube Q1 is controlled to realize the power control and voltage control of the overall circuit.

[0033] The above realizes a non-isolated dual active bridge circuit, which eliminates the limitation of high-frequency transformer in isolated dual active bridge circuit, can be applied in cost and volume sensitive, high dynamic response speed requirement, and may exist unbalanced saturation current scene, and the above circuit arranges the reactor between the two switch tube half-bridge circuits according to the topology characteristics, combined with the control of the duty cycle of switch tube, can reduce or eliminate the common mode voltage between the two capacitors, reduce the insulation design requirement in electrical isolation, and is beneficial to anti-interference design.

[0034] As Figure 3 , a non-isolated dual active bridge circuit, specifically a two-phase full-bridge non-isolated dual active bridge circuit, comprising a first side parallel circuit and a second side parallel circuit.

[0035] The first side parallel circuit comprises a first capacitor C H , a first switch tube half-bridge circuit and a second switch tube half-bridge circuit in parallel, the first switch tube half-bridge circuit comprises switch tube S1 and switch tube S2 in series, and the second switch tube half-bridge circuit comprises switch tube S3 and switch tube S4 in series. The connection of switch tube S1 and switch tube S2 is the midpoint A of the first switch tube half-bridge circuit, the connection of switch tube S3 and switch tube S4 is the midpoint B of the second switch tube half-bridge circuit, and the connection of first capacitor C H , switch tube S2 and switch tube S4 is ground potential G2.

[0036] The second side parallel circuit comprises a second capacitor C L, third switch tube half bridge circuit and fourth switch tube half bridge circuit, the third switch tube half bridge circuit includes switch tube Q1 and switch tube Q2 in series, the fourth switch tube half bridge circuit includes switch tube Q3 and switch tube Q4 in series.The connection of switch tube Q1 and switch tube Q2 is the midpoint a of the third switch tube half bridge circuit, the connection of switch tube Q3 and switch tube Q4 is the midpoint b of the fourth switch tube half bridge circuit, and the second capacitor C L , the connection of switch tube Q2 and switch tube Q4 is ground potential G2

[0037] The midpoint A of the first switch tube half bridge circuit and the midpoint a of the third switch tube half bridge circuit are connected by the reactor L1, and the midpoint B of the second switch tube half bridge circuit and the midpoint b of the fourth switch tube half bridge circuit are connected by the reactor L2, that is, the reactors are arranged in parallel, the impedance of the reactor L1 and the reactor L2 is equal, and the ground potential G1 of the first side parallel circuit and the ground potential G2 of the second side parallel circuit are connected by the clamping resistance R C Connection.

[0038] Similarly, in the above-mentioned circuit, there will be a common-mode voltage between the two side capacitors, which needs to be reduced or eliminated by the reactor and the corresponding suppression method, in an embodiment of the present application, based on the above-mentioned circuit, a common-mode voltage suppression method is disclosed, comprising: sending control signals to all switch tubes, so that the duty cycles of switch tube S1 and switch tube S2 are complementary, the duty cycles of switch tube S3 and switch tube S4 are complementary, the duty cycles of switch tube S1 and switch tube S4 are consistent, the duty cycles of switch tube Q1 and switch tube Q2 are complementary, the duty cycles of switch tube Q3 and switch tube Q4 are complementary, the duty cycles of switch tube Q1 and switch tube Q4 are consistent, and the duty cycles of switch tube S1 and switch tube Q1 are consistent, to suppress the common-mode voltage of the non-isolated dual active bridge circuit.

[0039] Specifically as follows:

[0040] S1) In the initial state, the ground potential G1 is taken as the basis ground potential, because the on-resistance of the semiconductor device is very large when it is not turned on, it is considered that the potential of the ground potential G2 is unknown, and the potential of the ground potential G2 is clamped to the vicinity of the ground potential G1 by the clamping resistance R C .

[0041] S2) When all switch tubes are normally emitted, the duty cycles of switch tube S1 and switch tube S2 are complementary, the duty cycles of switch tube S3 and switch tube S4 are complementary, the duty cycles of switch tube S1 and switch tube S4 are consistent, the duty cycles of switch tube Q1 and switch tube Q2 are complementary, the duty cycles of switch tube Q3 and switch tube Q4 are complementary, the duty cycles of switch tube Q1 and switch tube Q4 are consistent, and the duty cycles of switch tube S1 and switch tube Q1 are consistent, the power control of the two side parallel circuits is realized by the phase shift angle between switch tube S1 and switch tube Q1, so that the potential difference between the ground potential G1 and the ground potential G2 can be reduced to a minimum, such as Figure 4As shown.

[0042] In the above circuit, since there is no series connection of capacitors, there is no need for voltage equalization control, but the switch tubes Q1, Q4 need to be switched at the same time, the switch tubes Q2, Q3 need to be switched at the same time, the switch tubes S1, S4 need to be switched at the same time, and the switch tubes S2, S3 need to be switched at the same time, and then the phase shift angle between the switch tube S1 and the switch tube Q1 is controlled to realize power control and voltage control of the overall circuit.

[0043] The above realizes a non-isolated dual active bridge circuit, eliminates the limitation of the high-frequency transformer in the isolated dual active bridge circuit, can be applied in scenarios that are sensitive to cost and volume, require high dynamic response speed, and may have unbalanced saturation current, and the above short circuit arranges the reactor between the two switch tube half-bridge circuits according to the circuit topology characteristics, in combination with the control of the duty cycle of the switch tube, can reduce or eliminate the common-mode voltage between the two capacitors, reduce the insulation design requirement in electrical isolation, and is conducive to anti-interference design.

[0044] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and modifications without departing from the technical principles of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A non-isolated dual active bridge circuit, characterized in that, Includes a first-side parallel circuit and a second-side parallel circuit; The first parallel circuit includes a first capacitor series circuit and a first switching transistor half-bridge circuit connected in parallel. The first capacitor series circuit includes a capacitor C connected in series. H1 and capacitor C H2 The second-side parallel circuit includes a second capacitor series circuit and a second switching transistor half-bridge circuit connected in parallel. The second capacitor series circuit includes a capacitor C connected in series. L1 and capacitor C L2 ; The midpoint A of the first switching transistor half-bridge circuit and the midpoint a of the second switching transistor half-bridge circuit are connected by a reactor L1. The midpoint B of the first capacitor series circuit and the midpoint b of the second capacitor series circuit are connected. The ground potential G1 of the first parallel circuit and the ground potential G2 of the second parallel circuit are connected by a clamping resistor R. C connect.

2. The non-isolated dual active bridge circuit according to claim 1, characterized in that, The first switching half-bridge circuit includes switching transistors S1 and S2 connected in series; the second switching half-bridge circuit includes switching transistors Q1 and Q2 connected in series; and capacitor C... H2 The connection point between the transistor S2 and the switch is at ground potential G1, and the capacitor C... L2 The connection point between the transistor Q2 and the switch is at ground potential G2.

3. A common-mode voltage suppression method for a non-isolated dual active bridge circuit according to claim 2, characterized in that, include: Control signals are sent to all switches to make the duty cycles of switches S1 and S2 complementary, the duty cycles of switches Q1 and Q2 complementary, and the duty cycles of switches S1 and Q1 consistent, thereby suppressing the common-mode voltage of the non-isolated dual active bridge circuit.

4. The common-mode voltage suppression method for a non-isolated dual active bridge circuit according to claim 3, characterized in that, Initially, the ground potentials G1 and G2 of the non-isolated dual active bridge circuit are not equal.

5. A non-isolated dual active bridge circuit, characterized in that, Includes a first-side parallel circuit and a second-side parallel circuit; The first parallel circuit includes a first capacitor C connected in parallel. H The first switching transistor half-bridge circuit and the second switching transistor half-bridge circuit, the second side parallel circuit includes the second capacitor C connected in parallel. L The third-switch half-bridge circuit and the fourth-switch half-bridge circuit; The midpoint A of the first switching half-bridge circuit and the midpoint a of the third switching half-bridge circuit are connected by reactor L1. The midpoint B of the second switching half-bridge circuit and the midpoint b of the fourth switching half-bridge circuit are connected by reactor L2. The ground potential G1 of the first parallel circuit and the ground potential G2 of the second parallel circuit are connected by clamping resistor R. C connect.

6. A non-isolated dual active bridge circuit according to claim 5, characterized in that, The first switching half-bridge circuit includes switching transistors S1 and S2 connected in series; the second switching half-bridge circuit includes switching transistors S3 and S4 connected in series; the third switching half-bridge circuit includes switching transistors Q1 and Q2 connected in series; the fourth switching half-bridge circuit includes switching transistors Q3 and Q4 connected in series; and the first capacitor C... H The connection point between switching transistors S2 and S4 is at ground potential G2, and the second capacitor C... L The connection point between switching transistors Q2 and Q4 is at ground potential G2.

7. A non-isolated dual active bridge circuit according to claim 5, characterized in that, The impedances of reactors L1 and L2 are equal.

8. A common-mode voltage suppression method for a non-isolated dual active bridge circuit according to claim 6, characterized in that, include: Control signals are sent to all switches to make the duty cycles of switches S1 and S2 complementary, switches S3 and S4 complementary, switches S1 and S4 have the same duty cycle, switches Q1 and Q2 complementary, switches Q3 and Q4 complementary, switches Q1 and Q4 have the same duty cycle, and switches S1 and Q1 have the same duty cycle, thus suppressing the common-mode voltage of the non-isolated dual active bridge circuit.

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