A current source input converter based on an array of bidirectional voltage regulator diodes

Abstract

This application discloses a current source input converter based on a bidirectional Zener diode array; relating to the power supply field, it solves the problems of low efficiency, lack of redundancy protection, and high heat dissipation pressure of current source input converters. The bidirectional Zener diode array, in conjunction with a full-bridge rectifier circuit, enables the converter to adapt to any polarity of the input current. Regardless of the polarity of the constant current source, it can clamp and rectify it into a unidirectional DC bus voltage. The input terminals of the first DC / DC converter circuit and the second DC / DC converter circuit are connected in parallel, and their output terminals are also connected in parallel, forming a hot backup architecture with parallel input and parallel output. When one DC / DC converter circuit fails and stops working, the other continues to supply power to the load. The voltage regulation circuit detects the DC bus voltage and controls the conduction of the bypass current circuit to bypass excess current to ground. The bypass circuit diverts excess current, reducing the current flowing through the bidirectional Zener diode array and thus reducing the power consumption of the Zener diode array.

Description

Technical Field

[0001] This application relates to the field of power supplies, and in particular to a current source input converter based on a bidirectional Zener diode array. Background Technology

[0002] In applications such as deep-sea observation networks, submarine communication base stations, and long-distance DC microgrids, where transmission distances can reach tens or even hundreds of kilometers, power supply systems typically employ high-voltage constant current sources (CCS) to overcome line voltage drops and reduce transmission losses. Under this current-source power supply architecture, the end-load devices need to convert a constant input current into a stable DC voltage via a current-source input converter to meet the power demands of the downstream electronic equipment.

[0003] like Figure 1 As shown, existing current source input converters typically use a single-phase Zener diode matrix as the input, followed by a DC-DC converter and a load. The DC-DC converter uses isolated or non-isolated circuit topologies, converting the current source into a more stable voltage source through the Zener diode matrix. The disadvantages are that the Zener diode matrix input current can only flow in one phase, the DC-DC converter lacks a main backup circuit, and when the DC-DC circuit shuts down due to a problem, the load will stop working; when the relay equipment consumes relatively little power, most of the power loss will be consumed by the Zener diode matrix, resulting in low converter efficiency and making heat dissipation of the Zener diode matrix difficult to handle.

[0004] Therefore, how to solve the problems of low efficiency, lack of redundancy protection, and high heat dissipation pressure of current source input converters is a technical problem that urgently needs to be solved by those in this field. Summary of the Invention

[0005] The purpose of this application is to provide a current source input converter based on a bidirectional Zener diode array.

[0006] To solve the above-mentioned technical problems, this application provides a current source input converter based on a bidirectional Zener diode array, including: a bidirectional Zener diode array, a full-bridge rectifier circuit, a first DC / DC converter circuit, a second DC / DC converter circuit, a voltage regulation circuit, and a bypass current circuit; The input terminal of the bidirectional Zener diode array is connected to a constant current source to bidirectionally clamp the input current and output a clamping voltage. The input terminal of the full-bridge rectifier circuit is connected to the output terminal of the bidirectional Zener diode array, which is used to convert the clamping voltage of arbitrary polarity into a DC bus voltage in one direction. The input terminals of the first DC / DC converter circuit and the second DC / DC converter circuit are both connected in parallel to the output terminal of the full-bridge rectifier circuit; the output terminals of the first DC / DC converter circuit and the second DC / DC converter circuit are both connected in parallel to the load; the first DC / DC converter circuit and the second DC / DC converter circuit constitute a hot-standby architecture with parallel inputs and parallel outputs. The detection terminal of the voltage regulation circuit is connected to the output terminal of the full-bridge rectifier circuit, and the output terminal of the voltage regulation circuit is connected to the control terminal of the bypass current circuit, for detecting the DC bus voltage and outputting a control signal; The input terminal of the bypass current circuit is connected to the output terminal of the full-bridge rectifier circuit, and the output terminal of the bypass current circuit is grounded. It is used to control the circuit to be grounded according to the control signal, so that part of the input current is bypassed to ground.

[0007] Optionally, the current source input converter based on the bidirectional Zener diode array mentioned above also includes: an EMI filter circuit; The EMI filter circuit is connected between the input terminal of the full-bridge rectifier circuit and the output terminal of the bidirectional Zener diode array.

[0008] Optionally, in the above-mentioned current source input converter based on a bidirectional Zener diode array, the bidirectional Zener diode array includes multiple parallel Zener diode branches; Each of the Zener diode branches is connected in series with at least one pair of Zener diodes in reverse series and at least one thermistor.

[0009] Optionally, in the above-mentioned current source input converter based on a bidirectional Zener diode array, the full-bridge rectifier circuit includes: two rectifier units; the rectifier unit is a full-bridge rectifier bridge composed of four rectifier diodes; The input terminals of both rectifier units are connected in parallel to the output terminal of the EMI filter circuit, and the output terminals of both rectifier units are connected in parallel to the input terminals of the first DC / DC converter circuit and the second DC / DC converter circuit.

[0010] Optionally, in the above-mentioned current source input converter based on a bidirectional Zener diode array, the first DC / DC conversion circuit and the second DC / DC conversion circuit have the same structure, including: a first switch, a second switch, a third switch, a fourth switch, a first resonant inductor, a first resonant capacitor, and a transformer; The first terminal of the first switching transistor is connected to the first output terminal of the rectifier unit; the second terminal of the first switching transistor is connected to the first terminal of the second switching transistor and the first terminal of the first resonant inductor; the second terminal of the second switching transistor is connected to the second output terminal of the rectifier unit and the first terminal of the first resonant capacitor; the second terminal of the first resonant inductor is connected to the first primary terminal of the transformer; the second terminal of the first resonant capacitor is connected to the second primary terminal of the transformer; the first secondary terminal of the transformer is connected to the first terminal of the third switching transistor; the second secondary terminal of the transformer is connected to the first terminal of the fourth switching transistor; the second terminal of the third switching transistor is connected to the second terminal of the fourth switching transistor and serves as the first output terminal connected to the load; the intermediate tap of the secondary winding of the transformer serves as the second output terminal connected to the load.

[0011] Optionally, in the above-mentioned current source input converter based on a bidirectional Zener diode array, the voltage regulation circuit includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, an operational amplifier, and a reference Zener diode; The output terminal of the full-bridge rectifier circuit is connected to the first terminal of the first resistor. The second terminal of the first resistor is connected to the first terminal of the first capacitor, the first terminal of the second resistor, and the non-inverting input terminal of the operational amplifier. The second terminals of the first capacitor and the second resistor are grounded. The inverting input terminal of the operational amplifier is connected to the first terminal of the second capacitor, the reference power supply terminal, the first terminal of the third capacitor, and the first terminal of the fifth capacitor. The second terminal of the second capacitor is grounded. The second terminal of the third capacitor is connected to the first terminal of the third resistor. The second terminal of the third resistor is connected to the second terminal of the fifth capacitor, the output terminal of the operational amplifier, and the ground terminal. The output terminal of the operational amplifier is connected to the first terminal of the fourth resistor. The second terminal of the fourth resistor is connected to the negative terminal of the reference Zener diode, the first terminal of the sixth capacitor, and the first terminal of the fifth resistor. The positive terminal of the reference Zener diode, the second terminal of the sixth capacitor, and the second terminal of the fifth resistor are grounded. The second terminal of the fourth resistor serves as the output terminal of the voltage regulation circuit.

[0012] Optionally, in the above-mentioned current source input converter based on a bidirectional Zener diode array, the bypass current circuit includes: a sixth resistor, a fifth switching transistor, and multiple power resistors; The output terminal of the voltage regulation circuit is connected to the control terminal of the fifth switching transistor, and the second terminal of the fifth switching transistor is grounded through the sixth resistor; the first terminal of the fifth switching transistor is connected in series with each of the power resistors to the output terminal of the full-bridge rectifier circuit.

[0013] Optionally, the current source input converter based on the bidirectional Zener diode array mentioned above also includes: a varistor; The varistor is connected in parallel between the output terminals of the bidirectional Zener diode array.

[0014] Optionally, the current source input converter based on the bidirectional Zener diode array mentioned above also includes: a filter capacitor; The filter capacitor is connected in parallel between the output terminals of the first DC / DC converter circuit and the second DC / DC converter circuit.

[0015] Optionally, the above-mentioned current source input converter based on a bidirectional Zener diode array further includes: Two reverse protection circuits; The two anti-reverse circuits are respectively connected to the output terminals of the first DC / DC converter circuit and the second DC / DC converter circuit to prevent current from flowing in the opposite direction.

[0016] The current source input converter based on a bidirectional Zener diode array provided in this application, in conjunction with a full-bridge rectifier circuit, enables the converter to adapt to any polarity of the input current. Regardless of the polarity of the constant current source, it can clamp and rectify it into a unidirectional DC bus voltage, greatly improving system adaptability and reliability. The input terminals and output terminals of the first DC / DC conversion circuit and the second DC / DC conversion circuit are connected in parallel, forming an input-parallel-output (IPOP) hot backup architecture. When one DC / DC conversion circuit fails and stops working, the other can still continue to supply power to the load, avoiding system downtime due to the failure of a single module. The voltage regulation circuit detects the DC bus voltage and controls the conduction of the bypass current circuit, bypassing excess current to ground. The bypass circuit actively diverts excess current, directly reducing the current flowing through the bidirectional Zener diode array, thereby reducing the power consumption of the Zener diode array and the heat generation, thus improving the overall conversion efficiency. Attached Figure Description

[0017] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This application provides a schematic diagram of a current source input converter based on a bidirectional Zener diode array as an embodiment of the present application; Figure 2 This application provides a circuit diagram of a current source input converter based on a bidirectional Zener diode array. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this application.

[0020] The core of this application is to provide a current source input converter based on a bidirectional Zener diode array.

[0021] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] This application provides a current source input converter based on a bidirectional Zener diode array, such as... Figure 1 As shown, it includes: a bidirectional Zener diode array 11, a full-bridge rectifier circuit 12, a first DC / DC converter circuit 13, a second DC / DC converter circuit 14, a voltage regulation circuit 15, and a bypass current circuit 16; the input terminal of the bidirectional Zener diode array 11 is connected to a constant current source for bidirectional clamping of the input current and outputting a clamping voltage; the input terminal of the full-bridge rectifier circuit 12 is connected to the output terminal of the bidirectional Zener diode array 11, for converting the clamping voltage of arbitrary polarity into a DC bus voltage of unidirectional direction; the input terminals of the first DC / DC converter circuit 13 and the second DC / DC converter circuit 14 are both connected in parallel to the output terminal of the full-bridge rectifier circuit 12; the first DC... The outputs of the first DC / DC converter circuit 13 and the second DC / DC converter circuit 14 are both connected in parallel to the load. The first DC / DC converter circuit 13 and the second DC / DC converter circuit 14 form a hot backup architecture with parallel inputs and parallel outputs. The detection terminal of the voltage regulation circuit 15 is connected to the output terminal of the full-bridge rectifier circuit 12, and the output terminal of the voltage regulation circuit 15 is connected to the control terminal of the bypass current circuit 16, which is used to detect the DC bus voltage and output a control signal. The input terminal of the bypass current circuit 16 is connected to the output terminal of the full-bridge rectifier circuit 12, and the output terminal of the bypass current circuit 16 is grounded, which is used to control the circuit to conduct and ground according to the control signal, so that part of the input current is bypassed to ground.

[0023] This embodiment provides a current source input converter based on a bidirectional Zener diode array 11, suitable for power supply scenarios such as deep-sea observation networks, submarine communication base stations, or long-distance DC microgrids. In these scenarios, power transmission distances can reach tens or even hundreds of kilometers, and the power supply system typically uses a high-voltage constant current source for feeding to overcome line voltage drop and reduce transmission losses. The converter in this embodiment is used to convert a constant input current into a stable DC voltage to meet the power requirements of downstream electronic equipment.

[0024] See Figure 1 As shown, the converter in this embodiment mainly includes a bidirectional Zener diode array 11, a full-bridge rectifier circuit 12, a first DC / DC converter circuit 13, a second DC / DC converter circuit 14, a voltage regulation circuit 15, and a bypass current circuit 16.

[0025] The input terminal of the bidirectional Zener diode array 11 is connected to a constant current source. This array is used to bidirectionally clamp the input current and output a clamping voltage. Bidirectional clamping means that the array can limit both forward and reverse overvoltages, controlling the voltage amplitude within a preset safe range. This characteristic makes the converter insensitive to input polarity; the array can operate normally regardless of whether the output terminal of the constant current source is connected in either direction, thereby improving the convenience of engineering installation and the safety of the system.

[0026] The input terminal of the full-bridge rectifier circuit 12 is connected to the output terminal of the bidirectional Zener diode array 11. The function of this circuit is to convert a clamping voltage of arbitrary polarity into a DC bus voltage in a single direction. Specifically, the full-bridge rectifier circuit 12 consists of four rectifier diodes forming a closed commutation loop. Regardless of whether the polarity of the output terminal of the bidirectional Zener diode array 11 is positive or negative, the output terminal of the full-bridge rectifier circuit 12 always outputs a DC voltage of a single polarity. This design further enhances the input polarity insensitivity characteristic, ensuring that subsequent circuits always receive a DC bus voltage of the correct polarity.

[0027] The input terminals of both the first DC / DC converter circuit 13 and the second DC / DC converter circuit 14 are connected in parallel to the output terminal of the full-bridge rectifier circuit 12. That is, both converters are connected to the same DC bus. Simultaneously, the output terminals of both the first DC / DC converter circuit 13 and the second DC / DC converter circuit 14 are connected in parallel to the load (the load is...). Figure 1 (RL shown).

[0028] The first DC / DC converter circuit 13 and the second DC / DC converter circuit 14 form a hot-standby architecture with parallel inputs and parallel outputs. Hot standby means that the second DC / DC converter circuit 14 is in a energized ready state when the first DC / DC converter circuit 13 is operating normally. That is, although the standby circuit does not bear the main power output, its internal circuitry is powered on, and its control circuitry is in standby mode. When the first DC / DC converter circuit 13 fails or its output voltage drops, the second DC / DC converter circuit 14 can automatically take over the output, maintaining the continuity of power supply to the load.

[0029] This embodiment does not strictly limit which of the first DC / DC converter circuit 13 and the second DC / DC converter circuit 14 is the primary and which is the backup. In practice, the two converters can be equal, or the primary and backup roles can be designated by external control signals. Based on the above principle, this hot backup architecture significantly improves the power supply reliability of the system and avoids the risk of load power outage due to a single point of failure.

[0030] The detection terminal of the voltage regulation circuit 15 is connected to the output terminal of the full-bridge rectifier circuit 12, which is also connected to the DC bus. The output terminal of the voltage regulation circuit 15 is connected to the control terminal of the bypass current circuit 16. The voltage regulation circuit 15 is used to detect the DC bus voltage and output a control signal based on the detection result.

[0031] It should be noted that the core function of the voltage regulation circuit 15 is to sample the bus voltage and compare it with a preset reference voltage. When the bus voltage exceeds the preset threshold, it indicates that the input power is greater than the power consumed by the load, and the excess energy is causing the bus voltage to rise. At this time, the voltage regulation circuit 15 outputs an effective control signal to drive the bypass current circuit 16 to operate.

[0032] The input terminal of the bypass current circuit 16 is connected to the output terminal of the full-bridge rectifier circuit 12, which is also connected to the positive terminal of the DC bus. The output terminal of the bypass current circuit 16 is grounded. The bypass current circuit 16 is used to control its internal circuit to conduct to ground according to the control signal output by the voltage regulation circuit 15, so that part of the input current is bypassed to ground.

[0033] Specifically, the bypass current circuit 16 includes a switching transistor and a power resistor. When the control signal turns on the switching transistor, a portion of the current on the DC bus flows directly to ground through the power resistor and the switching transistor, forming a bypass path. As a result, the current flowing into the first DC / DC converter circuit 13 and the second DC / DC converter circuit 14 is reduced accordingly, leading to a decrease in the output voltage of the bidirectional Zener diode array 11.

[0034] Based on the above principle, when the load lightens or the input current source increases, the voltage regulation circuit 15 detects an increase in the bus voltage and immediately controls the bypass current circuit 16 to conduct, bypassing the excess current to ground. At this time, the current flowing through the bidirectional Zener diode array 11 is maintained at the minimum level that only allows it to reverse break down and output a stable voltage. As the current flowing through the array decreases, its junction temperature decreases, and the output voltage also decreases accordingly. Under the premise of energy conservation, the input power decreases while the output power remains unchanged, thus significantly reducing the power loss of the system and greatly improving the efficiency of the converter.

[0035] In summary, the current source input converter based on the bidirectional Zener diode array 11 provided in this application, in conjunction with the full-bridge rectifier circuit 12, enables the converter to adapt to any polarity of the input current. Regardless of the polarity of the constant current source, it can clamp and rectify it into a unidirectional DC bus voltage, greatly improving the system's adaptability and reliability. The input terminals of the first DC / DC converter circuit 13 and the second DC / DC converter circuit 14 are connected in parallel, and their output terminals are also connected in parallel, forming an input-parallel-output (IPOP) hot backup architecture. When one of the DC / DC converter circuits fails and stops working, the other can still continue to supply power to the load, avoiding system downtime caused by a single module failure. The voltage regulation circuit 15 detects the DC bus voltage and controls the conduction of the bypass current circuit 16 to bypass excess current to ground. The bypass circuit actively diverts excess current, directly reducing the current flowing through the bidirectional Zener diode array 11, thereby reducing the power consumption of the Zener diode array and the heat generation, thus improving the overall conversion efficiency.

[0036] Specifically, it also includes: EMI filter circuit 17; EMI filter circuit 17 is connected between the input terminal of full-bridge rectifier circuit 12 and the output terminal of bidirectional Zener diode array 11.

[0037] like Figure 2 As shown, in this embodiment, an electromagnetic interference (EMI) filter circuit is added between the output terminal of the bidirectional Zener diode array 11 and the full-bridge rectifier circuit 12. This EMI filter circuit 17 typically includes common-mode inductors L1 and L3 and safety capacitors CX1, CX2, and CX4.

[0038] Due to the complex power supply environment in the deep sea, electromagnetic interference may exist in the lines. The EMI filter circuit 17 is used to suppress electromagnetic interference generated by the high-speed switching of power devices inside the converter, preventing interference signals from being conducted to the external power grid or other equipment through the power lines. At the same time, this filter circuit can also prevent interference from the external power lines from entering the converter, avoiding interference signals from causing control circuit malfunctions or output waveform distortion.

[0039] Specifically, the bidirectional Zener diode array 11 includes multiple parallel Zener diode branches; each Zener diode branch is connected in series with at least one pair of Zener diodes connected in reverse series and at least one thermistor.

[0040] First, it should be noted that the purpose of using multiple parallel branches is to achieve redundancy and fault tolerance. When the Zener diode in one branch fails to open, the other parallel branches can still maintain their clamping function, and the system will not completely lose its overvoltage protection capability due to the failure of a single device.

[0041] like Figure 2 As shown on the left, the bidirectional Zener diode array 11 is not a single device, but rather comprises multiple parallel Zener diode branches. Each branch is connected in series with at least one pair of Zener diodes in reverse series and at least one thermistor. The presence of at least one pair of Zener diodes in reverse series in each branch means that the branch can clamp both forward and reverse overvoltages. That is, regardless of the current direction, the branch can limit the voltage to near the breakdown voltage of the Zener diodes.

[0042] In addition, a thermistor is connected in series in each branch. In this embodiment, the thermistor can be a positive temperature coefficient thermistor, also known as a PTC thermistor. Utilizing its positive temperature coefficient characteristic, when the current in a branch is too large, causing the temperature to rise, the thermistor resistance increases, thereby limiting the current in that branch and achieving automatic current sharing.

[0043] When a branch experiences a larger current due to differences in device characteristics or heat dissipation conditions, the PTC thermistor in that branch heats up due to increased power consumption, causing its resistance to increase. This increased resistance leads to a larger voltage drop in that branch, thus suppressing further current growth. Conversely, branches with smaller currents maintain a smaller equivalent resistance due to lower temperature rise, allowing the current to be compensated. Based on this principle, current deviations in parallel branches are dynamically suppressed, reducing the dependence on strict device parameter matching and significantly improving the consistency of current distribution when multiple branches are connected in parallel.

[0044] Specifically, the full-bridge rectifier circuit 12 includes: two rectifier units; each rectifier unit is a full-bridge rectifier bridge composed of four rectifier diodes; the input terminals of both rectifier units are connected in parallel to the output terminal of the EMI filter circuit 17, and the output terminals of both rectifier units are connected in parallel to the input terminals of the first DC / DC converter circuit 13 and the second DC / DC converter circuit 14.

[0045] like Figure 2As shown, the full-bridge rectifier circuit 12 includes two rectifier units. Each rectifier unit consists of four rectifier diodes forming a full-bridge rectifier bridge. The input terminals of the two rectifier units are connected in parallel to the output terminal of the EMI filter circuit 17, and their output terminals are connected in parallel to the input terminal of the DC / DC converter circuit.

[0046] The purpose of using two parallel rectifier units is to improve the reliability of the rectification process. If one rectifier unit fails, the other can still maintain its rectification function, preventing the entire converter from shutting down due to the failure of a single rectifier unit. Furthermore, the parallel connection of the two rectifier units also shares the input current, reducing the current stress on each rectifier diode, which helps to reduce device temperature rise and extend its lifespan.

[0047] This embodiment does not impose a strict limit on the number of rectifier units. Depending on the actual power level and reliability requirements, one rectifier unit can be used, or two or more rectifier units can be connected in parallel. Connecting two rectifier units in parallel is a preferred solution that balances reliability and cost.

[0048] Specifically, the first DC / DC converter circuit 13 and the second DC / DC converter circuit 14 have the same structure, including: a first switch Q1, a second switch Q2, a third switch Q3, a fourth switch Q4, a first resonant inductor Lr1, a first resonant capacitor Cr1, and a transformer T1; the first terminal of the first switch Q1 is connected to the first output terminal of the rectifier unit, the second terminal of the first switch Q1 is connected to the first terminal of the second switch Q2 and the first terminal of the first resonant inductor Lr1, the second terminal of the second switch Q2 is connected to the second output terminal of the rectifier unit and the first terminal of the first resonant capacitor Cr1; the second terminal of the first resonant inductor Lr1 is connected to the first primary terminal of the transformer; the second terminal of the first resonant capacitor Cr1 is connected to the second primary terminal of the transformer; the first secondary terminal of the transformer is connected to the first terminal of the third switch Q3, and the second secondary terminal of the transformer is connected to the first terminal of the fourth switch Q4; the second terminal of the third switch Q3 and the second terminal of the fourth switch Q4 are connected and serve as the first output terminal connected to the load; the intermediate tap of the secondary terminal of the transformer serves as the second output terminal connected to the load.

[0049] like Figure 2As shown in the middle section, the first DC / DC converter circuit 13 and the second DC / DC converter circuit 14 have the same structure, both employing a half-bridge LLC (inductor-inductor-capacitor) resonant topology. The first switch Q1 and the second switch Q2 are alternately turned on in a complementary manner, with a dead time between them to prevent shoot-through. When the first switch Q1 is on and the second switch Q2 is off, current flows from the positive terminal of the DC bus through the first switch Q1, the first resonant inductor Lr1, the transformer primary, and the first resonant capacitor Cr1 back to the negative terminal of the DC bus, forming a positive excitation circuit. When the first switch Q1 is off and the second switch Q2 is on, the energy stored in the first resonant capacitor Cr1 forms a reverse discharge path through the transformer primary, the first resonant inductor Lr1, and the second switch Q2. The first resonant inductor Lr1, the first resonant capacitor Cr1, and the transformer's magnetizing inductance together constitute a resonant network. By controlling the switching frequencies of the first switch Q1 and the second switch Q2, the switches can be turned on at zero voltage crossings, thereby achieving zero-voltage turn-on and significantly reducing switching losses.

[0050] The switching transistors Q1 and Q2, resonant inductor Lr1, resonant capacitor Cr1, transformer T1, and secondary synchronous rectifiers Q3 and Q4 of the first DC / DC converter circuit 13 correspond to the switching transistors Q1-1 and Q2-1, resonant inductor Lr1-1, resonant capacitor Cr1-1, transformer T1-1, and secondary synchronous rectifiers Q3-1 and Q4-1 of the second DC / DC converter circuit 14.

[0051] By utilizing the soft-switching characteristics of the LLC resonant converter, zero-voltage turn-on and zero-current turn-off of the switching transistors are achieved, thereby significantly reducing switching losses and improving conversion efficiency. The parallel input and parallel output architecture allows the two converters to share the load current equally, realizing power expansion and hot backup.

[0052] Specifically, the voltage regulation circuit 15 includes: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, an operational amplifier U1, and a reference Zener diode DL; the output terminal of the full-bridge rectifier circuit 12 is connected to the first terminal of the first resistor, and the second terminal of the first resistor is connected to the first terminal of the first capacitor C1, the first terminal of the second resistor R2, and the non-inverting input terminal of the operational amplifier U1; the second terminals of the first capacitor C1 and the second resistor R2 are grounded; the inverting input terminal of the operational amplifier U1 is connected to the first terminal of the second capacitor C2 and the reference power supply terminal. The first terminal of the third capacitor C3 and the first terminal of the fifth capacitor C5 are connected; the second terminal of the second capacitor C2 is grounded; the second terminal of the third capacitor C3 is connected to the first terminal of the third resistor R3, the second terminal of the third resistor R3 is connected to the second terminal of the fifth capacitor C5, the output terminal of the operational amplifier U1, and the ground terminal; the output terminal of the operational amplifier U1 is connected to the first terminal of the fourth resistor R4, the second terminal of the fourth resistor R4 is connected to the negative terminal of the reference Zener diode DL, the first terminal of the sixth capacitor C6, and the first terminal of the fifth resistor R5; the positive terminal of the reference Zener diode DL, the second terminal of the sixth capacitor C6, and the second terminal of the fifth resistor R5 are grounded; the second terminal of the fourth resistor R4 serves as the output terminal of the voltage regulation circuit 15.

[0053] The first and second resistors R2 form a voltage divider network. The DC bus voltage, after being divided by the first and second resistors R2, yields a sampling voltage proportional to the bus voltage at the non-inverting input. The first capacitor C1 is connected in parallel across the second resistor R2, acting as a filter to eliminate high-frequency noise components in the sampling voltage. A stable reference voltage is provided at the reference power supply terminal for comparison with the sampling voltage. The fifth capacitor C5, the third capacitor C3, and the third resistor R3 form a compensation network connected between the inverting input and output of operational amplifier U1 to ensure the stability of the voltage regulation loop. Operational amplifier U1 compares the sampling voltage at the non-inverting input with the reference voltage at the inverting input. When the sampling voltage is lower than the reference voltage, operational amplifier U1 outputs a low level. When the sampling voltage is higher than the reference voltage, operational amplifier U1 outputs a high level. The fourth resistor R4 acts as a current-limiting resistor, protecting the subsequent reference Zener diode DL and the fifth resistor R5. The reference Zener diode DL clamps the output level of the voltage regulation circuit 15 within a stable range, preventing excessively high control signal voltage from damaging the switching transistor in the bypass current circuit 16. The sixth capacitor C6 acts as a filter, making the output control signal smoother.

[0054] Based on the above structure, the voltage regulation circuit 15 realizes real-time detection and threshold comparison of the DC bus voltage, and outputs the comparison result to the bypass current circuit 16 in the form of a switch control signal. This analog control method has fast response speed and high reliability, and does not require the participation of a digital controller, which helps to reduce system cost and complexity.

[0055] Specifically, the bypass current circuit 16 includes: a sixth resistor R6, a fifth switch Q5, and multiple power resistors RES_D2PAK; the output terminal of the voltage regulation circuit 15 is connected to the control terminal of the fifth switch Q5, and the second terminal of the fifth switch Q5 is grounded through the sixth resistor R6; the first terminal of the fifth switch Q5 is connected in series with each power resistor to the output terminal of the full-bridge rectifier circuit 12.

[0056] The fifth switch, Q5, is the core actuator of the bypass current circuit 16. When the control signal output by the voltage regulation circuit 15 turns on the fifth switch, Q5, the bypass channel is opened. The fifth switch, Q5, can be a metal-oxide-semiconductor field-effect transistor (MOSFET) or an insulated-gate bipolar transistor (IGBT). This embodiment does not strictly limit the type of switch, as long as its control terminal can accept the signal output by the voltage regulation circuit 15 and achieve fast switching.

[0057] Power resistors are components that dissipate bypass current. When the fifth switch Q5 is turned on, a portion of the current on the DC bus flows to ground through the power resistor and the fifth switch Q5. The power resistor converts this electrical energy into heat and dissipates it. Using multiple power resistors in parallel can distribute the heat load, reduce the temperature rise of individual resistors, and improve heat dissipation efficiency. In addition, power resistors can be surface-mount packaged, which facilitates better heat dissipation on printed circuit boards.

[0058] The sixth resistor R6 is connected between the second terminal of the fifth switching transistor Q5 and ground to limit the maximum current flowing through the fifth switching transistor Q5, thus providing overcurrent protection. When the bypass current is too large, the voltage drop across the sixth resistor R6 increases, indirectly limiting the conduction of the fifth switching transistor Q5 and preventing the transistor from being damaged due to overcurrent.

[0059] When the load is light or the input current source increases, the voltage regulation circuit 15 detects the rise in bus voltage and outputs a high-level control signal to turn on the fifth switch Q5. At this time, part of the input current bypasses to ground through the power resistor and the fifth switch Q5, and the current flowing into the first DC / DC converter circuit 13 and the second DC / DC converter circuit 14 is reduced accordingly.

[0060] As the current flowing into the bidirectional Zener diode array 11 decreases, its junction temperature drops, and the output voltage also decreases. With the output power remaining constant, the input power decreases, thus reducing the system's power loss. Therefore, the bypass current circuit 16 and the voltage regulation circuit 15 work together to form a closed-loop control system, dynamically maintaining the bus voltage within a preset range, thereby maintaining high system efficiency under different load conditions.

[0061] Specifically, it also includes: a varistor; the varistor is connected in parallel between the output terminals of the bidirectional Zener diode array 11.

[0062] A varistor is connected in parallel between the output terminals of the bidirectional Zener diode array 11, that is, in parallel between the two output terminals of the bidirectional Zener diode array 11.

[0063] A varistor is a voltage-sensitive resistive element. Under normal operating voltage, the varistor exhibits high resistance and almost no current flows through it, having no impact on the normal operation of the converter. When an overvoltage surge occurs in the circuit, such as a voltage spike caused by lightning strikes, inductive load switching, or power grid fluctuations, the varistor's resistance drops rapidly within a very short time, switching from a high-resistance state to a low-resistance state. This bypasses the overvoltage energy in the form of current, thereby clamping the voltage to a safe level.

[0064] It should be noted that the varistor and the bidirectional Zener diode array 11 complement each other in overvoltage protection. The bidirectional Zener diode array 11 is mainly used for continuous overvoltage clamping, with a fast response speed, but its energy absorption capacity is relatively limited. The varistor, on the other hand, is mainly used to absorb transient, high-energy surge voltages, and its energy tolerance is strong. Using them in parallel can simultaneously achieve comprehensive protection against both continuous overvoltage and transient surges, significantly improving the converter's overvoltage resistance.

[0065] Furthermore, the varistor is reusable. After a surge, the varistor can return to a high-impedance standby state and can handle subsequent surges without replacement. This feature makes the converter in this embodiment more durable in harsh power supply environments.

[0066] Specifically, it also includes: a filter capacitor; the filter capacitor is connected in parallel between the output terminals of the first DC / DC converter circuit 13 and the second DC / DC converter circuit 14.

[0067] The main function of the filter capacitor is to smooth the output voltage and reduce the ripple component in the output voltage. Although both the first DC / DC converter circuit 13 and the second DC / DC converter circuit 14 output DC voltage, due to the switching action, a certain frequency of ripple voltage is unavoidable at the output terminal. The filter capacitor utilizes its charging and discharging characteristics to absorb charge when the output voltage rises and release charge when the output voltage falls, thereby playing a smoothing and filtering role.

[0068] Generally, aluminum electrolytic capacitors can be used as filter capacitors because they have large capacitance and low cost, making them suitable for output filtering. To further filter out high-frequency ripple, a small-capacity ceramic capacitor can be connected in parallel next to the aluminum electrolytic capacitor. This embodiment does not impose strict limitations on the type and number of filter capacitors, as long as their total capacitance is sufficient to meet the output ripple requirements.

[0069] On the other hand, the outputs of the first DC / DC converter circuit 13 and the second DC / DC converter circuit 14 are connected in parallel and then connected to the filter capacitor. Due to the presence of the filter capacitor, when the two converters perform hot backup switching, the energy stored in the capacitor can provide temporary power to the load at the moment of switching, further reducing the voltage drop during the switching process.

[0070] Specifically, such as Figure 1 As shown, it also includes: two anti-reverse circuits 18; the two anti-reverse circuits 18 are respectively connected to the output terminals of the first DC / DC converter circuit 13 and the second DC / DC converter circuit 14 to prevent current from flowing in reverse.

[0071] Because the first DC / DC converter circuit 13 and the second DC / DC converter circuit 14 adopt an input-parallel and output-parallel architecture, it is difficult to ensure that the output voltages of the two modules are absolutely identical in actual operation. Without reverse current protection measures, the module with the slightly higher output voltage may flow current back to the module with the slightly lower output voltage, forming a circulating current between the modules. This will not only cause additional power loss, but may also lead to overheating or even damage to the modules.

[0072] Therefore, by setting up these two reverse protection circuits, the unidirectional conductivity of diodes is utilized to ensure that current can only flow from the secondary side of the transformer to the load, and not between the two DC / DC converter circuits. In other words, even if the instantaneous voltage of one module is lower than that of the other, the reverse protection circuit can block current backflow, forcing the two modules to independently supply power to the load, thus achieving true hot backup and current sharing protection.

[0073] The reverse current protection circuit can be implemented using diodes connected in series. Forward current can flow smoothly through the diodes, while reverse current is blocked. This embodiment is not strictly limited; any circuit structure that can prevent reverse current flow is acceptable. The output reverse current protection circuit works in conjunction with the hot-backup architecture, further improving the system's reliability and security.

[0074] The current source input converter based on a bidirectional Zener diode array 11 provided in this application has been described in detail above. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of this application.

[0075] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

Claims

1. A current source input converter based on a bidirectional Zener diode array, characterized in that, include: Bidirectional Zener diode array, full-bridge rectifier circuit, first DC / DC converter circuit, second DC / DC converter circuit, voltage regulation circuit, bypass current circuit; The input terminal of the bidirectional Zener diode array is connected to a constant current source to bidirectionally clamp the input current and output a clamping voltage. The input terminal of the full-bridge rectifier circuit is connected to the output terminal of the bidirectional Zener diode array, which is used to convert the clamping voltage of arbitrary polarity into a DC bus voltage in one direction. The input terminals of the first DC / DC converter circuit and the second DC / DC converter circuit are both connected in parallel to the output terminal of the full-bridge rectifier circuit; the output terminals of the first DC / DC converter circuit and the second DC / DC converter circuit are both connected in parallel to the load; the first DC / DC converter circuit and the second DC / DC converter circuit constitute a hot-standby architecture with parallel inputs and parallel outputs. The detection terminal of the voltage regulation circuit is connected to the output terminal of the full-bridge rectifier circuit, and the output terminal of the voltage regulation circuit is connected to the control terminal of the bypass current circuit, for detecting the DC bus voltage and outputting a control signal; The input terminal of the bypass current circuit is connected to the output terminal of the full-bridge rectifier circuit, and the output terminal of the bypass current circuit is grounded. It is used to control the circuit to be grounded according to the control signal, so that part of the input current is bypassed to ground.

2. The current source input converter based on a bidirectional Zener diode array according to claim 1, characterized in that, Also includes: EMI filter circuit; The EMI filter circuit is connected between the input terminal of the full-bridge rectifier circuit and the output terminal of the bidirectional Zener diode array.

3. The current source input converter based on a bidirectional Zener diode array according to claim 1, characterized in that, The bidirectional Zener diode array includes multiple parallel Zener diode branches; Each of the Zener diode branches is connected in series with at least one pair of Zener diodes in reverse series and at least one thermistor.

4. The current source input converter based on a bidirectional Zener diode array according to claim 2, characterized in that, The full-bridge rectifier circuit includes: two rectifier units; each rectifier unit is a full-bridge rectifier bridge composed of four rectifier diodes; The input terminals of both rectifier units are connected in parallel to the output terminal of the EMI filter circuit, and the output terminals of both rectifier units are connected in parallel to the input terminals of the first DC / DC converter circuit and the second DC / DC converter circuit.

5. The current source input converter based on a bidirectional Zener diode array according to claim 4, characterized in that, The first DC / DC converter circuit and the second DC / DC converter circuit have the same structure, including: a first switching transistor, a second switching transistor, a third switching transistor, a fourth switching transistor, a first resonant inductor, a first resonant capacitor, and a transformer; The first terminal of the first switching transistor is connected to the first output terminal of the rectifier unit; the second terminal of the first switching transistor is connected to the first terminal of the second switching transistor and the first terminal of the first resonant inductor; the second terminal of the second switching transistor is connected to the second output terminal of the rectifier unit and the first terminal of the first resonant capacitor; the second terminal of the first resonant inductor is connected to the first primary terminal of the transformer; the second terminal of the first resonant capacitor is connected to the second primary terminal of the transformer; the first secondary terminal of the transformer is connected to the first terminal of the third switching transistor; the second secondary terminal of the transformer is connected to the first terminal of the fourth switching transistor; the second terminal of the third switching transistor is connected to the second terminal of the fourth switching transistor and serves as the first output terminal connected to the load; the intermediate tap of the secondary winding of the transformer serves as the second output terminal connected to the load.

6. The current source input converter based on a bidirectional Zener diode array according to claim 1, characterized in that, The voltage regulation circuit includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, an operational amplifier, and a reference Zener diode; The output terminal of the full-bridge rectifier circuit is connected to the first terminal of the first resistor. The second terminal of the first resistor is connected to the first terminal of the first capacitor, the first terminal of the second resistor, and the non-inverting input terminal of the operational amplifier. The second terminals of the first capacitor and the second resistor are grounded. The inverting input terminal of the operational amplifier is connected to the first terminal of the second capacitor, the reference power supply terminal, the first terminal of the third capacitor, and the first terminal of the fifth capacitor. The second terminal of the second capacitor is grounded. The second terminal of the third capacitor is connected to the first terminal of the third resistor. The second terminal of the third resistor is connected to the second terminal of the fifth capacitor, the output terminal of the operational amplifier, and the ground terminal. The output terminal of the operational amplifier is connected to the first terminal of the fourth resistor. The second terminal of the fourth resistor is connected to the negative terminal of the reference Zener diode, the first terminal of the sixth capacitor, and the first terminal of the fifth resistor. The positive terminal of the reference Zener diode, the second terminal of the sixth capacitor, and the second terminal of the fifth resistor are grounded. The second terminal of the fourth resistor serves as the output terminal of the voltage regulation circuit.

7. The current source input converter based on a bidirectional Zener diode array according to claim 6, characterized in that, The bypass current circuit includes: a sixth resistor, a fifth switching transistor, and multiple power resistors; The output terminal of the voltage regulation circuit is connected to the control terminal of the fifth switching transistor, and the second terminal of the fifth switching transistor is grounded through the sixth resistor; the first terminal of the fifth switching transistor is connected in series with each of the power resistors to the output terminal of the full-bridge rectifier circuit.

8. The current source input converter based on a bidirectional Zener diode array according to claim 1, characterized in that, Also includes: Varistor; The varistor is connected in parallel between the output terminals of the bidirectional Zener diode array.

9. The current source input converter based on a bidirectional Zener diode array according to claim 1, characterized in that, It also includes: filter capacitors; The filter capacitor is connected in parallel between the output terminals of the first DC / DC converter circuit and the second DC / DC converter circuit.

10. The current source input converter based on a bidirectional Zener diode array according to claim 1, characterized in that, Also includes: Two reverse protection circuits; The two anti-reverse circuits are respectively connected to the output terminals of the first DC / DC converter circuit and the second DC / DC converter circuit to prevent current from flowing in the opposite direction.

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