Multi-voltage alternating current input direct current power supply device, method and equipment

Abstract

The invention provides a multi-voltage alternating-current input direct-current power supply device, method and equipment, and relates to the technical field of direct-current power supply. By arranging the rectifying circuit, the boosting circuit and the two same DC / DC converters, under the condition of different alternating current input voltages, the boosting magnitude and the connection relationship between the DC / DC converters and the boosting circuit are adjusted based on the magnitude relationship between the rectified voltage and the target voltage, so that the input side voltage of each DC / DC converter is constant at the target voltage. Therefore, when the input voltage is high, although the rectified voltage is higher than the target voltage, the voltage borne by the DC / DC converter is smaller than the rectified voltage, the voltage withstanding requirement is lowered, a low-voltage-withstanding device can be adopted, and the manufacturing cost is lowered; and when the input voltage is relatively low, each DC / DC converter participates in direct current conversion of the target voltage, so that the utilization rate is improved, and the performance waste caused by adopting a high-voltage-resistant device is also avoided.

Description

Technical Field

[0001] The present invention relates to the field of direct current (DC) power supply technology, and in particular to a DC power supply device, method, and equipment with multi-voltage AC input. Background Art

[0002] The basic function of a DC power supply is to convert AC input power into DC output power. DC power supplies that are compatible with a variety of AC input voltages offer strong versatility and adaptability, making them important in many scenarios. For example, a DC power supply that is compatible with both three-phase and single-phase inputs allows users to choose between three-phase input in industrial scenarios or single-phase input in residential scenarios, depending on their actual power supply needs, without having to change the power supply equipment. A DC power supply typically includes rectification, voltage regulation, and DC / DC conversion.

[0003] When compatibility with multiple AC input voltages is required, to overcome the problem of excessively high or low voltages, one approach is to adjust the voltage by installing a boost circuit and a buck circuit after rectification before inputting it into a DC / DC converter. However, installing both a boost circuit and a buck circuit makes the circuit complex and the manufacturing cost high. Another approach, to accommodate large input voltage fluctuations, is to use a DC / DC converter after rectification and the boost circuit to adjust the output voltage according to the varying input voltage. However, this approach results in a wide input voltage fluctuation range for the DC / DC converter, requiring a high-voltage DC / DC converter to accommodate the highest input voltage conditions, resulting in high manufacturing costs. Furthermore, in low-voltage applications, the performance of a high-voltage DC / DC converter is wasted, resulting in low performance utilization. Summary of the Invention

[0004] The embodiments of the present invention provide a DC power supply device, method and equipment with multi-voltage AC input to solve the problems of high cost and low performance utilization of high-voltage resistant devices in the case of multi-voltage AC input.

[0005] In a first aspect, an embodiment of the present invention provides a DC power supply device with multi-voltage AC input, comprising: a rectifier circuit, a boost circuit and a controller, and two identical DC / DC converters;

[0006] The rectifier circuit inputs AC power and outputs the rectified voltage to the boost circuit;

[0007] The boost circuit outputs a boosted voltage;

[0008] The controller is used to control the boosted voltage to be twice the target voltage when the rectified voltage is greater than the target voltage, and to control the input sides of the two DC / DC converters to be connected in series between the positive output terminal and the negative output terminal of the boost circuit, so that the input side voltage of any DC / DC converter is the target voltage;

[0009] The controller is used to control the boosted voltage to be the target voltage when the rectified voltage is not greater than the target voltage, and to control the input sides of the two DC / DC converters to be connected in parallel between the positive output terminal and the negative output terminal of the boost circuit, so that the input side voltage of any DC / DC converter is the target voltage.

[0010] In a possible implementation, two filter capacitors are further included;

[0011] A filter capacitor is connected in parallel between the positive input and negative input of any DC / DC converter.

[0012] In a possible implementation, a double-pole double-throw switch is further included; the double-pole double-throw switch includes four static contacts and two moving contacts;

[0013] The first static contact is connected to the negative output terminal of the boost circuit and the negative input terminal of the second DC / DC converter; the second static contact is connected to the fourth static contact; and the third static contact is connected to the positive output terminal of the boost circuit and the positive input terminal of the first DC / DC converter.

[0014] The first moving contact is connected to the negative input terminal of the first DC / DC converter; the second moving contact is connected to the positive input terminal of the second DC / DC converter;

[0015] When the first moving contact is connected to the second static contact and the second moving contact is connected to the fourth static contact, the input sides of the two DC / DC converters are controlled to be connected in series between the positive output terminal and the negative output terminal of the boost circuit;

[0016] When the first moving contact is connected to the first static contact and the second moving contact is connected to the third static contact, the input sides of the two DC / DC converters are controlled to be connected in parallel between the positive output terminal and the negative output terminal of the boost circuit.

[0017] In a possible implementation, the positive output terminals of the two DC / DC converters are connected to each other, and the negative output terminals of the two DC / DC converters are connected to each other, wherein the output voltages of the two DC / DC converters are the same.

[0018] In a possible implementation, the voltage boosting circuit includes a boost circuit.

[0019] In a possible implementation, it further includes a judgment circuit;

[0020] The input side of the input judgment circuit is connected to the input side of the rectifier circuit;

[0021] The input judgment circuit is used to judge whether the rectified voltage is greater than the target voltage according to the input side voltage of the rectifier circuit, and send the judgment result to the controller.

[0022] In a possible implementation, the input side of the rectifier circuit is used to input three-phase alternating current or single-phase alternating current.

[0023] In one possible implementation, the target voltage is between 310V and 540V; when three-phase AC power is input, it is determined that the rectified voltage is greater than the target voltage; when single-phase AC power is input, it is determined that the rectified voltage is not greater than the target voltage.

[0024] In a second aspect, an embodiment of the present invention provides a DC power supply method with multi-voltage AC input, which is applied to a DC power supply device with multi-voltage AC input in any possible implementation of the first aspect; the method includes:

[0025] Get the rectified voltage and target voltage;

[0026] determining whether the rectified voltage is greater than a target voltage;

[0027] If the rectified voltage is greater than the target voltage, the boosted voltage is controlled to be twice the target voltage, and the input sides of the two DC / DC converters are connected in series between the positive output terminal and the negative output terminal of the boost circuit so that the input side voltage of any DC / DC converter is the target voltage;

[0028] If the rectified voltage is not greater than the target voltage, the boosted voltage is controlled to be the target voltage, and the input sides of the two DC / DC converters are controlled to be connected in parallel between the positive output terminal and the negative output terminal of the boost circuit, so that the input side voltage of any DC / DC converter is the target voltage.

[0029] In a third aspect, an embodiment of the present invention provides a DC power supply device with multi-voltage AC input, comprising the DC power supply device with multi-voltage AC input in any possible implementation of the first aspect.

[0030] Embodiments of the present invention provide a DC power supply device, method, and apparatus with multi-voltage AC input. By providing a rectifier circuit, a boost circuit, and two identical DC / DC converters, under different AC input voltage conditions, the boost size and the connection relationship between the DC / DC converter and the boost circuit are adjusted based on the relationship between the rectified voltage and the target voltage, so that the input side voltage of each DC / DC converter is constant at the target voltage.

[0031] When the AC input voltage is high and the rectified voltage is high, the voltage is boosted to twice the target voltage. The two series-connected DC / DC converters divide the voltage, and the input voltage of each DC / DC converter is the target voltage. When the AC input voltage is low and the rectified voltage is low, the voltage is boosted to the target voltage. The two parallel-connected DC / DC converters have the same input voltage, and the input voltage of each DC / DC converter is the target voltage.

[0032] Therefore, when the input voltage is high, although the rectified voltage is higher than the target voltage, the voltage carried by the DC / DC converter is lower than the rectified voltage, which reduces the voltage resistance requirement and allows the use of low-voltage components, reducing manufacturing costs. When the input voltage is low, each DC / DC converter participates in the DC conversion of the target voltage, improving utilization and avoiding performance waste when using high-voltage components.

[0033] In addition, by keeping the input voltage of the DC / DC converter constant at the target voltage, the frequency of the DC / DC converter is reduced compared to the case where the input voltage fluctuates greatly, thereby improving the conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic structural diagram of a DC power supply device with multi-voltage AC input provided by an embodiment of the present invention;

[0035] Figure 2 1 is a structural diagram of a first equivalent circuit of a DC power supply device provided by an embodiment of the present invention;

[0036] Figure 3 It is a structural schematic diagram of a second equivalent circuit of a DC power supply device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0037] To help those skilled in the art better understand this solution, the following will clearly describe the technical solutions in the embodiments of this solution in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of this solution, not all of it. Based on the embodiments of this solution, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of this solution.

[0038] Throughout the specification, claims, and accompanying figures of this solution, the term "including" and any variations thereof mean "including, but not limited to," and are intended to cover non-exclusive inclusions and are not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc., are used to distinguish between different objects, not to describe a specific order.

[0039] The following is a detailed description of the implementation of the present invention with reference to the accompanying drawings:

[0040] DC power supplies compatible with multiple AC input voltages have numerous applications. In addition to the three-phase and single-phase input scenarios described above, this also includes consumer electronics chargers. For example, mobile phone chargers must adapt to mains voltages in different countries and regions, such as 110V or 220V, ensuring that mobile phones can charge properly without having to carry multiple chargers of different specifications.

[0041] A DC power supply typically includes rectification, voltage regulation, and DC / DC conversion. Rectification converts input AC power into DC. The rectified DC voltage may fluctuate or not meet actual requirements. Voltage regulation stabilizes it at an appropriate value. The DC / DC converter further processes the rectified and voltage-regulated DC power, converting it into a stable, specific DC output voltage.

[0042] Under various AC input voltage conditions, the AC input voltage varies significantly. This may be caused by switching the AC power source or by voltage fluctuations within the same AC power source.

[0043] In the existing method, in order to adapt to different voltage levels, high-voltage resistant devices need to be set to adapt to the highest input voltage conditions, which results in high manufacturing costs. For example, a high-voltage resistant DC / DC converter is set. Although high-voltage resistant devices can adapt to high-voltage conditions, high-voltage resistance is not required in low-voltage application scenarios. As a result, the performance of the high-voltage resistant DC / DC converter is wasted and the performance utilization rate is low. For example, high-voltage resistant applications usually need to process larger power, so the power capacity of the high-voltage resistant DC / DC converter is often larger. This means that it can provide a larger output current at high voltage to meet the needs of high-power loads. However, in low-voltage application scenarios, the power capacity is often not fully utilized.

[0044] The embodiments of the present invention adjust the boost size and the connection relationship between the DC / DC converter and the boost circuit according to the AC input voltage of different voltages, so that the voltage on the input side of the DC / DC converter is constant at the target voltage, reducing the withstand voltage requirement of the DC / DC converter, and solving the problems of high cost and low performance utilization of high-voltage components in the case of multi-voltage AC input.

[0045] Figure 1 Schematic diagram of the structure of a DC power supply device with multiple AC voltage inputs provided by an embodiment of the present invention. Figure 1 A DC power supply device with multi-voltage AC input includes: a rectifier circuit, a boost circuit and a controller, and two identical DC / DC converters; the rectifier circuit inputs AC power and outputs a rectified voltage to the boost circuit; the boost circuit outputs the boosted voltage; the controller is used to control the boosted voltage to be twice the target voltage when the rectified voltage is greater than the target voltage, and control the input sides of the two DC / DC converters to be connected in series between the positive output terminal and the negative output terminal of the boost circuit so that the input side voltage of any DC / DC converter is the target voltage; the controller is used to control the boosted voltage to be the target voltage when the rectified voltage is not greater than the target voltage, and control the input sides of the two DC / DC converters to be connected in parallel between the positive output terminal and the negative output terminal of the boost circuit so that the input side voltage of any DC / DC converter is the target voltage.

[0046] In some embodiments, a DC power supply device is configured to input AC power and output DC power. For example, the DC power supply device can input multiple voltage levels. Furthermore, the DC power supply device can output a constant DC voltage at varying input voltages.

[0047] In some embodiments, a DC power supply device with multi-voltage AC input includes: a rectifier circuit, a boost circuit and a controller, and two identical DC / DC converters.

[0048] The functions of each component are described below.

[0049] Exemplarily, a rectifier circuit converts input AC power into DC power. Rectifier circuits are typically composed of unidirectionally conductive electronic components, such as diodes. Regardless of how the input AC power changes, the output current remains in the same direction after passing through the rectifier circuit, thereby achieving conversion from AC to DC power. Furthermore, the rectifier circuit can be a half-wave rectifier, a full-wave rectifier, or a bridge rectifier.

[0050] Exemplarily, a boost circuit is a circuit module that can boost an input DC voltage to a required higher DC voltage.

[0051] For example, a DC / DC converter is an electronic device that converts a DC voltage into another DC voltage and is widely used in circuits that require different voltage levels.

[0052] The following describes the input and output ports of each component.

[0053] In some embodiments, the rectifier circuit includes a positive output terminal and a negative output terminal. Furthermore, based on the number of phases of the input AC power and the internal structure of the rectifier circuit, the input terminals of the rectifier circuit can be three input terminals or two input terminals. For example, three input terminals can input three-phase AC power, while two input terminals can input single-phase AC power. To ensure compatibility between three-phase and single-phase, the input terminals of the rectifier circuit can be three input terminals.

[0054] In some embodiments, the input side of the boost circuit includes a positive input terminal and a negative input terminal, and the output side includes a positive output terminal and a negative output terminal.

[0055] In some embodiments, the input side of the DC / DC converter includes a positive input terminal and a negative input terminal, and the output side includes a positive output terminal and a negative output terminal.

[0056] The following describes the connection relationship between the various components.

[0057] In some embodiments, the output side of the rectifier circuit is connected to the input side of the boost circuit. For example, the positive output terminal of the rectifier circuit is connected to the positive input terminal of the boost circuit; and the negative output terminal of the rectifier circuit is connected to the negative input terminal of the boost circuit.

[0058] In some embodiments, the rectifier circuit inputs alternating current and outputs a rectified voltage to a boost circuit;

[0059] In some embodiments, the boost circuit outputs a boosted voltage;

[0060] In some embodiments, the DC / DC converter outputs a converted DC voltage.

[0061] It should be noted that the output side of the boost circuit is connected to the input side of the DC / DC converter. Here, there are two DC / DC converters, and the connection between the boost circuit and the two DC / DC converters is not fixed. Instead, the controller adaptively switches based on changes in the AC input voltage. The control logic for this switching is described in detail below.

[0062] In some embodiments, the controller is configured to control the boosted voltage to be twice the target voltage when the rectified voltage is greater than the target voltage, and to control the input sides of the two DC / DC converters to be connected in series between the positive output terminal and the negative output terminal of the boost circuit, so that the input side voltage of any DC / DC converter is the target voltage;

[0063] It should be noted that the target voltage is ultimately applied to the input side of the DC / DC converter. The specific range or value of the target voltage can be determined based on the specific application conditions of the DC power supply device. For example, the target voltage can be determined based on the designed input voltage range, and thus be within the designed input voltage range. For another example, the target voltage range can be determined based on the DC / DC converter's output DC voltage range, thereby determining the DC / DC converter's input voltage range. In summary, the target voltage range is a preset voltage range determined during the DC power supply device design phase.

[0064] Based on the established rectifier circuit structure, the input AC voltage is positively correlated with the rectified voltage. The higher the input AC voltage, the higher the rectified voltage. Therefore, when the input AC voltage is too high, the rectified voltage will exceed the target voltage. On the one hand, when the rectified voltage exceeds the target voltage, the controller controls the boost circuit to boost the rectified voltage to twice the target voltage. On the other hand, when the rectified voltage exceeds the target voltage, the controller also controls the input side of the two DC / DC converters to be connected in series between the positive and negative output terminals of the boost circuit. These two aspects of control complement each other, with the ultimate goal of ensuring that the input side voltage of either DC / DC converter reaches the target voltage.

[0065] Exemplarily, the input sides of two DC / DC converters are connected in series between the positive and negative output terminals of a boost circuit, meaning: the positive output terminal of the boost circuit is connected to the positive input terminal of the first DC / DC converter, the negative input terminal of the first DC / DC converter is connected to the positive input terminal of the second DC / DC converter, and the negative input terminal of the second DC / DC converter is connected to the negative output terminal of the boost circuit. That is, the positive and negative input terminals of the first DC / DC converter, and the positive and negative input terminals of the second DC / DC converter are connected in series between the positive and negative output terminals of the boost circuit, respectively. Thus, the input sides of the two identical DC / DC converters connected in series, through series voltage division, each carry 1 / 2 of the boost circuit output voltage, i.e., 1 / 2 of twice the target voltage, ensuring that the input voltage of either DC / DC converter is the target voltage.

[0066] The above describes the case where the rectified voltage is greater than the target voltage. The following describes the case where it is not greater than the target voltage.

[0067] In some other embodiments, the controller is used to control the boosted voltage to be the target voltage when the rectified voltage is not greater than the target voltage, and to control the input sides of the two DC / DC converters to be connected in parallel between the positive output terminal and the negative output terminal of the boost circuit, so that the input side voltage of any DC / DC converter is the target voltage.

[0068] When the input AC voltage is too low, the rectified voltage will not exceed the target voltage. On the one hand, when the rectified voltage is not greater than the target voltage, the controller controls the boost circuit to boost the rectified voltage to double the target voltage. On the other hand, when the rectified voltage is not greater than the target voltage, the controller also controls the input sides of the two DC / DC converters to be connected in parallel between the positive and negative output terminals of the boost circuit. These two aspects of control complement each other, and the ultimate goal is to ensure that the input voltage of each DC / DC converter reaches the target voltage.

[0069] For example, connecting the input sides of two DC / DC converters in parallel between the positive and negative output terminals of a boost circuit means: the positive output terminal of the boost circuit is connected to the positive input terminal of the first DC / DC converter, and the negative output terminal of the boost circuit is connected to the negative input terminal of the first DC / DC converter; the positive output terminal of the boost circuit is connected to the positive input terminal of the second DC / DC converter, and the negative output terminal of the boost circuit is connected to the negative input terminal of the second DC / DC converter. That is, the positive and negative input terminals of the first DC / DC converter are connected in parallel with the positive and negative output terminals of the boost circuit, and the positive and negative input terminals of the second DC / DC converter are connected in parallel with the positive and negative output terminals of the boost circuit. As a result, the input-side voltages of the two identical DC / DC converters connected in parallel are the same, namely, the output voltage of the boost circuit, i.e., the target voltage, ensuring that the input-side voltage of any DC / DC converter is the target voltage.

[0070] The embodiment of the present invention provides a rectifier circuit, a boost circuit, and two identical DC / DC converters. Under different AC input voltage conditions, the boost magnitude and the connection relationship between the DC / DC converter and the boost circuit are adjusted based on the magnitude relationship between the rectified voltage and the target voltage, so that the input side voltage of each DC / DC converter is constant at the target voltage.

[0071] When the AC input voltage is high and the rectified voltage is high, the voltage is boosted to twice the target voltage. The two series-connected DC / DC converters divide the voltage, and the input voltage of each DC / DC converter is the target voltage. When the AC input voltage is low and the rectified voltage is low, the voltage is boosted to the target voltage. The two parallel-connected DC / DC converters have the same input voltage, and the input voltage of each DC / DC converter is the target voltage.

[0072] Therefore, when the input voltage is high, although the rectified voltage is higher than the target voltage, the voltage carried by the DC / DC converter is lower than the rectified voltage, which reduces the voltage resistance requirement and allows the use of low-voltage components, reducing manufacturing costs. When the input voltage is low, each DC / DC converter participates in the DC conversion of the target voltage, improving utilization and avoiding performance waste when using high-voltage components.

[0073] In addition, by keeping the input voltage of the DC / DC converter constant at the target voltage, the frequency of the DC / DC converter is reduced compared to the case where the input voltage fluctuates greatly, thereby improving the conversion efficiency.

[0074] It should be noted that when the input voltage of a DC / DC converter is unstable, the DC / DC converter must adjust accordingly to output a stable voltage as the input voltage changes. The switching losses of a DC / DC converter primarily come from the energy loss of the switch tube during the on- and off-state transitions. When the input voltage fluctuates significantly, the switch tube needs to adjust its on- and off-state more frequently to maintain a stable output voltage. This causes the switch tube to operate at higher voltage and current change rates, resulting in greater switching losses. When the input voltage is constant, the operating state of the switch tube is relatively stable. Reducing the control frequency reduces the number of times the switch tube is turned on and off, and energy losses during the switching process are also reduced. Therefore, the input voltage of the DC / DC converter in this embodiment of the present invention is kept constant at the target voltage, which can improve the conversion efficiency of the DC / DC converter, reduce energy waste during the conversion process, and enable the converter to more efficiently convert input electrical energy into output electrical energy.

[0075] In some embodiments, the DC power supply device further includes a filter capacitor, which can stabilize the boosted voltage and reduce ripple.

[0076] Filter capacitors have the ability to store charge, thus bypassing AC components. The voltage output by the boost circuit is not an ideal DC voltage, but rather contains a certain AC component, known as ripple. The filter capacitor has a low impedance to the AC component, providing a low-resistance path for the AC ripple, allowing the ripple current to flow through the capacitor to ground, thereby reducing the ripple. That is, the boosted voltage may fluctuate to a certain extent. The filter capacitor can smooth these voltage fluctuations through its energy storage and release process, keeping the output voltage at a relatively stable level.

[0077] However, when the input voltage is unstable, high-voltage filter capacitors are required to accommodate the highest input voltage conditions, which results in high manufacturing costs. In low-voltage applications, the performance of high-voltage filter capacitors is wasted, resulting in low performance utilization.

[0078] It should be noted that, generally speaking, under the same capacitor structure and material, when the capacitor operates at a lower voltage, it can store relatively more charge, that is, it exhibits a larger capacitance. Since capacitors can achieve a larger capacity at low voltage, if capacitors originally designed for high voltage are used in some circuits that only require low voltage and small capacity, it is not cost-effective from a volume perspective. Because these capacitors designed for high voltage have special designs in structure and materials to meet high voltage requirements, resulting in a larger volume, and when used at low voltage, the advantage of their large capacity cannot be fully utilized, resulting in a waste of volume.

[0079] In a possible implementation, two filter capacitors are further included; one filter capacitor is connected in parallel between the positive input terminal and the negative input terminal of any DC / DC converter.

[0080] In the embodiment of the present invention, a filter capacitor is connected in parallel to the input side of each DC / DC converter. Based on the description of the voltage on the input side of the DC / DC converter in the above text, the required load voltage of the filter capacitor is reduced, and the use of high-voltage filter capacitors can be avoided. Instead, low-voltage devices are used, thereby reducing manufacturing costs.

[0081] Generally speaking, the design and manufacturing process of low-voltage filter capacitors is relatively simple. Because they do not require special insulation materials or more complex electrode structures to withstand high voltages, the manufacturing cost of the capacitor itself is reduced.

[0082] As mentioned earlier, low-voltage filter capacitors don't require increased plate spacing, thicker insulation, or larger plate areas to meet withstand voltage requirements, as high-voltage capacitors do. Therefore, for the same capacity, low-voltage capacitors can be smaller. This is particularly important for space-critical devices, freeing up space for other components and contributing to smaller and lighter devices.

[0083] Furthermore, a stable input voltage can reduce capacitor charge and discharge losses. If the capacitor voltage fluctuates significantly, a certain amount of energy will be lost in the capacitor during each charge and discharge process due to factors such as the capacitor's internal resistance. However, when the voltage is constant at the target voltage, the capacitor's charge and discharge process is relatively smooth, with a relatively small amplitude and frequency. This reduces energy loss during the charge and discharge process and further improves the effective utilization of the capacitor.

[0084] The following describes how to switch the connection method between the boost circuit and the DC / DC converter.

[0085] In one possible implementation, a double-pole double-throw switch is further included; the double-pole double-throw switch includes four static contacts and two moving contacts; the first static contact is connected to the negative output end of the boost circuit and the negative input end of the second DC / DC converter; the second static contact is connected to the fourth static contact; the third static contact is connected to the positive output end of the boost circuit and the positive input end of the first DC / DC converter; the first moving contact is connected to the negative input end of the first DC / DC converter; the second moving contact is connected to the positive input end of the second DC / DC converter; when the first moving contact is connected to the second static contact and the second moving contact is connected to the fourth static contact, the input sides of the two DC / DC converters are controlled to be connected in series between the positive output end and the negative output end of the boost circuit; when the first moving contact is connected to the first static contact and the second moving contact is connected to the third static contact, the input sides of the two DC / DC converters are controlled to be connected in parallel between the positive output end and the negative output end of the boost circuit.

[0086] Exemplarily, the four stationary contacts of the double-pole double-throw switch include a first stationary contact, a second stationary contact, a third stationary contact, and a fourth stationary contact.

[0087] Furthermore, the two movable contacts of the double-pole double-throw switch include a first movable contact and a second movable contact.

[0088] Exemplarily, when the first moving contact is connected to the second static contact and the second moving contact is connected to the fourth static contact, the input sides of the two DC / DC converters are controlled to be connected in series between the positive output terminal and the negative output terminal of the boost circuit. In this way, in the series state, the total voltage borne by the two DC / DC converters is equal to the output voltage of the boost circuit, and their currents are equal.

[0089] Furthermore, when the first moving contact is connected to the first static contact and the second moving contact is connected to the third static contact, the input sides of the two DC / DC converters are controlled to be connected in parallel between the positive output terminal and the negative output terminal of the boost circuit. In this connection mode, in the parallel state, the input voltages of the two DC / DC converters are equal to the output voltage of the boost circuit, and their currents are distributed according to their respective load conditions.

[0090] Exemplarily, the DC power supply device further includes a relay, which is used to switch the state of the double-pole double-throw switch under the control of the controller.

[0091] The embodiment of the present invention can conveniently change the connection mode (series or parallel) of the input sides of two DC / DC converters by switching the double-pole double-throw switch to meet different circuit requirements.

[0092] The following describes the connection method of the output sides of the two DC / DC converters.

[0093] In a possible implementation, the positive output terminals of the two DC / DC converters are connected to each other, and the negative output terminals of the two DC / DC converters are connected to each other, wherein the output voltages of the two DC / DC converters are the same.

[0094] It should be noted that the two DC / DC converters have the same internal parameters, such as input voltage and conversion efficiency, which allows them to have the same output voltage. In this connection method, since the output voltages of the two DC / DC converters are the same, when the positive output terminals are connected together, no current will flow between the two positive output terminals due to a voltage difference. Similarly, when the negative output terminals are connected together, no current will flow between the two negative output terminals due to a voltage difference.

[0095] The embodiment of the present invention connects the output ends of two DC-DC converters with the same output voltage in this way, so that they can jointly provide current to the load, thereby improving the output current capacity of the entire power supply system to meet the needs of high-power loads.

[0096] In a possible implementation, the voltage boosting circuit includes a boost circuit.

[0097] Exemplarily, the controller is configured to adjust the output voltage of the BOOST circuit according to an input voltage condition.

[0098] For example, the BOOST circuit can pre-stabilize the input voltage. During the operation of the BOOST circuit, the input voltage is first stabilized to ensure the accuracy and stability of the subsequent boost operation.

[0099] A boost circuit is a switching power supply circuit primarily composed of a switching transistor, an inductor, a diode, a capacitor, and a control circuit. During pre-regulation of the input voltage, the control circuit monitors changes in the input voltage in real time. If the input voltage fluctuates, the control circuit adjusts the on-time and off-time of the switching transistor based on feedback signals.

[0100] For example, when the input voltage decreases, the control circuit increases the on-time of the switch, allowing the inductor to store more energy. When the switch turns off, the inductor releases more energy, charging the capacitor through the diode, thereby increasing the output voltage. This compensates for the decrease in input voltage to a certain extent and achieves initial stabilization of the input voltage. Conversely, when the input voltage increases, the control circuit reduces the on-time of the switch, limiting the energy stored in the inductor and preventing the output voltage from rising excessively, keeping it within a relatively stable range.

[0101] The following describes how the controller determines the AC input voltage.

[0102] In one possible implementation, an input judgment circuit is further included; the input side of the input judgment circuit is connected to the input side of the rectifier circuit; the input judgment circuit is used to judge whether the rectified voltage is greater than the target voltage based on the input side voltage of the rectifier circuit, and send the judgment result to the controller.

[0103] It should be noted that, when the rectifier circuit structure is determined, the relationship between the input AC voltage and the rectified output voltage is usually determined. Therefore, the input voltage of the rectifier circuit can be used to determine whether the rectified voltage is greater than the target voltage.

[0104] In a possible implementation, the input side of the rectifier circuit is used to input three-phase alternating current or single-phase alternating current.

[0105] In one possible implementation, the target voltage is between 310V and 540V; when three-phase AC power is input, it is determined that the rectified voltage is greater than the target voltage; when single-phase AC power is input, it is determined that the rectified voltage is not greater than the target voltage.

[0106] The following is a comprehensive embodiment to illustrate the technical concept of the present invention. The embodiment of the present invention provides a DC power supply device compatible with three-phase and single-phase AC input. Figure 1 The DC power supply device includes a rectifier circuit, a BOOST boost circuit, a switching circuit, a filter capacitor, a DC / DC converter, an input judgment circuit and a controller.

[0107] The rectifier circuit converts the input AC power into DC power. The rectified voltage is 540V for three-phase input and 310V for single-phase input.

[0108] The BOOST circuit pre-stabilizes the input voltage. The filter capacitor stabilizes the boosted voltage to reduce ripple.

[0109] The DC / DC converter performs isolated power conversion, converting the input high voltage into the required voltage value. The output sides of the two DC / DC converters are connected in parallel.

[0110] The input judgment circuit samples and judges the input voltage to confirm whether the input is three-phase or single-phase AC.

[0111] The controller controls the boost circuit and the switching circuit according to input information provided by the input judgment circuit.

[0112] The switching circuit includes a double-pole double-throw switch and a relay to switch the connection mode between the filter capacitor and the DC / DC converter: when the input is three-phase, the filter capacitor and the DC / DC converter are in series; when the input is single-phase, the filter capacitor and the DC / DC converter are in parallel.

[0113] The embodiment of the present invention switches the connection mode of the boost circuit, filter capacitor and DC / DC converter according to the input voltage through a switching circuit; at the same time, the output voltage of the BOOST boost circuit is adjusted according to the input voltage. The following is a detailed description:

[0114] a) When three-phase input is used, the controller controls the BOOST circuit to boost 540V DC to 800V, and at the same time controls the relay contacts of the switching circuit to be on the normally closed side. Figure 2 This is a structural diagram of the first equivalent circuit of the DC power supply device provided by the embodiment of the present invention. Figure 2 shown.

[0115] At this point, the two sets of filter capacitors and the primary stages of the two DC / DC converters are connected in series, with the voltage across each capacitor and DC / DC converter being 400V.

[0116] The secondary outputs of the DC / DC converters are connected in parallel, and the current sharing function ensures that the power of the two DC / DC converters is similar, so that the voltage of the upper and lower parts of the series connection (filter capacitor and DC / DC converter) is basically consistent.

[0117] b) When single-phase input is used, the controller controls the BOOST circuit to boost the 310V DC power to 400V, and at the same time controls the relay contacts of the switching circuit to be on the normally open side. Figure 3 : is a structural diagram of a second equivalent circuit of a DC power supply device provided in an embodiment of the present invention. Figure 3 shown.

[0118] At this point, the two sets of filter capacitors and the primary stages of the two DC / DC converters are connected in parallel, and the voltage across each capacitor and DC / DC converter remains at 400V.

[0119] Beneficial effects of the embodiments of the present invention:

[0120] 1) The voltage on the filter capacitor is constant at 400V, which improves the utilization of the capacitor and reduces the ripple of the power supply.

[0121] 2) The input voltage of the DC / DC converter is constant at 400V. Compared with the input high voltage (540V), the input voltage of the DC / DC converter is low, so lower voltage components can be selected to reduce costs and improve efficiency.

[0122] At the same time, since the input voltage of the DC / DC converter is constant, the control frequency of the DC / DC converter changes less, thereby improving the conversion efficiency of the DC / DC converter.

[0123] An embodiment of the present invention provides a DC power supply method with multi-voltage AC input, which is applied to a DC power supply device with multi-voltage AC input in any of the above possible implementations; the method includes:

[0124] Get the rectified voltage and target voltage;

[0125] determining whether the rectified voltage is greater than a target voltage;

[0126] If the rectified voltage is greater than the target voltage, the boosted voltage is controlled to be twice the target voltage, and the input sides of the two DC / DC converters are connected in series between the positive output terminal and the negative output terminal of the boost circuit so that the input side voltage of any DC / DC converter is the target voltage;

[0127] If the rectified voltage is not greater than the target voltage, the boosted voltage is controlled to be the target voltage, and the input sides of the two DC / DC converters are controlled to be connected in parallel between the positive output terminal and the negative output terminal of the boost circuit, so that the input side voltage of any DC / DC converter is the target voltage.

[0128] An embodiment of the present invention provides a DC power supply device with multi-voltage AC input, including the DC power supply apparatus with multi-voltage AC input in any possible implementation manner described above.

[0129] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A DC power supply device with multiple AC voltage inputs, characterized in that: include: Rectifier circuit, boost circuit and controller, and two identical DC / DC converters; The rectifier circuit inputs AC power and outputs the rectified voltage to the boost circuit; The boost circuit outputs a boosted voltage; The controller is used to control the boosted voltage to be twice the target voltage when the rectified voltage is greater than the target voltage, and to control the input sides of the two DC / DC converters to be connected in series between the positive output terminal and the negative output terminal of the boost circuit, so that the input side voltage of any DC / DC converter is the target voltage; The controller is used to control the boosted voltage to be the target voltage when the rectified voltage is not greater than the target voltage, and to control the input sides of the two DC / DC converters to be connected in parallel between the positive output terminal and the negative output terminal of the boost circuit, so that the input side voltage of any DC / DC converter is the target voltage.

2. The DC power supply device with multi-voltage AC input according to claim 1, wherein: Also included are two filter capacitors; A filter capacitor is connected in parallel between the positive input and negative input of any DC / DC converter.

3. The DC power supply device with multi-voltage AC input according to claim 1, wherein: Also included is a double-pole double-throw switch; the double-pole double-throw switch includes four static contacts and two moving contacts; The first static contact is connected to the negative output terminal of the boost circuit and the negative input terminal of the second DC / DC converter; The second static contact is connected to the fourth static contact; the third static contact is connected to the positive output terminal of the boost circuit and the positive input terminal of the first DC / DC converter; The first moving contact is connected to the negative input terminal of the first DC / DC converter; the second moving contact is connected to the positive input terminal of the second DC / DC converter; When the first moving contact is connected to the second static contact and the second moving contact is connected to the fourth static contact, the input sides of the two DC / DC converters are controlled to be connected in series between the positive output terminal and the negative output terminal of the boost circuit; When the first moving contact is connected to the first static contact and the second moving contact is connected to the third static contact, the input sides of the two DC / DC converters are controlled to be connected in parallel between the positive output terminal and the negative output terminal of the boost circuit.

4. The DC power supply device with multi-voltage AC input according to claim 1, wherein: The positive output terminals of the two DC / DC converters are connected to each other, and the negative output terminals of the two DC / DC converters are connected to each other, wherein the output voltages of the two DC / DC converters are the same.

5. The DC power supply device with multi-voltage AC input according to claim 1, wherein: The boost circuit includes a boost circuit.

6. The DC power supply device with multi-voltage AC input according to claim 1, wherein: Also includes an input judgment circuit; The input side of the input judgment circuit is connected to the input side of the rectifier circuit; The input judgment circuit is used to judge whether the rectified voltage is greater than the target voltage according to the input side voltage of the rectifier circuit, and send the judgment result to the controller.

7. The DC power supply device with multiple AC voltage inputs according to claim 1, wherein: The input side of the rectifier circuit is used to input three-phase alternating current or single-phase alternating current.

8. The DC power supply device with multi-voltage AC input according to claim 7, characterized in that: The target voltage is between 310V and 540V; When three-phase AC power is input, it is determined that the rectified voltage is greater than the target voltage; When single-phase AC power is input, it is determined that the rectified voltage is not greater than the target voltage.

9. A DC power supply method with multiple AC voltage inputs, characterized in that: A DC power supply device with multi-voltage AC input as claimed in any one of claims 1 to 8; the method comprising: Get the rectified voltage and target voltage; determining whether the rectified voltage is greater than a target voltage; If the rectified voltage is greater than the target voltage, the boosted voltage is controlled to be twice the target voltage, and the input sides of the two DC / DC converters are connected in series between the positive output terminal and the negative output terminal of the boost circuit so that the input side voltage of any DC / DC converter is the target voltage; If the rectified voltage is not greater than the target voltage, the boosted voltage is controlled to be the target voltage, and the input sides of the two DC / DC converters are controlled to be connected in parallel between the positive output terminal and the negative output terminal of the boost circuit, so that the input side voltage of any DC / DC converter is the target voltage.

10. A DC power supply device with multiple AC voltage inputs, characterized in that: A DC power supply device with multi-voltage AC input comprising the device according to any one of claims 1 to 8.

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