Transformer secondary output circuit, switching power supply circuit, air conditioner

Abstract

The present invention provides a secondary output circuit of a transformer, a switching power supply circuit, and an air conditioner, wherein the secondary output circuit of the transformer includes: a first output circuit connected to a first load, used to output a first control voltage to the first load, wherein the first load is a load with fixed power consumption; a second output circuit connected to a second load, used to output a second control voltage to the second load, wherein the second load is a load with variable power consumption; a first voltage conversion circuit connected between the first output circuit and the first load, used to adjust the conversion load according to the voltage change rate of the second load. Through the present invention, the technical problem of high cross-regulation rate of multiple output circuits in the related art is solved, the cross-regulation rate of the switching power supply is improved, the switching power supply works more stably, and the reliable operation of the unit is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of circuits, and in particular to a secondary output circuit of a transformer, a switching power supply circuit, and an air conditioner. Background Art

[0002] In the related art, the power cross regulation rate of some switching power supplies is poor. When the voltage on the feedback loop suddenly increases or decreases, the voltage output by the other winding of the transformer for other loads may increase or decrease. At this time, the power on the load needs to be increased or reduced to keep the output of the switching power supply stable. However, since the power of the load is fixed, such as for a wired controller or for powering a built-in motor driver board, the control load cannot be changed, resulting in the failure to improve the power cross regulation rate.

[0003] With respect to the above-mentioned problems existing in the related technologies, no effective solutions have been found so far. Summary of the invention

[0004] The embodiments of the present invention provide a secondary output circuit of a transformer, a switching power supply circuit, and an air conditioner to solve the technical problem of high cross-regulation rate of multi-output circuits in the related art.

[0005] According to one embodiment of the present invention, a secondary output circuit of a transformer is provided, comprising: a first output circuit connected to a first load, for outputting a first control voltage to the first load, wherein the first load is a load with fixed power consumption; a second output circuit connected to a second load, for outputting a second control voltage to the second load, wherein the second load is a load with variable power consumption; and a first voltage conversion circuit connected between the first output circuit and the first load, for adjusting the conversion load according to the voltage change rate of the second load.

[0006] Optionally, the first voltage conversion circuit includes: a first voltage conversion sub-circuit, connected between the first output circuit and the first load, and used to convert the output voltage into the first control voltage based on a first conversion efficiency; a second voltage conversion sub-circuit, connected between the first output circuit and the first load, and used to convert the output voltage into the first control voltage based on a second conversion efficiency, wherein the first conversion efficiency is greater than the second conversion efficiency; a switching circuit, connected to the first voltage conversion sub-circuit and the second voltage conversion sub-circuit, and used to adjust the on-off state of the first voltage conversion sub-circuit and the second voltage conversion sub-circuit according to the voltage change rate.

[0007] Optionally, the first voltage conversion sub-circuit is a DC-DC conversion circuit, and the second voltage conversion sub-circuit is a low dropout linear regulator LDO.

[0008] Optionally, the circuit also includes: a voltage sampling circuit connected to the second load, for collecting the voltage value of the second load according to a sampling period; a control chip connected to the voltage sampling circuit and the first voltage conversion circuit, for calculating the voltage change rate of the second load according to the voltage value, generating an adjustment instruction based on the voltage change rate, and outputting the adjustment instruction to the first voltage conversion circuit.

[0009] Optionally, the control chip includes: a calculation module, used to calculate the voltage change rate d of the second load according to the following formula: d = (U12-U11) / t, wherein U11 and U12 are two consecutive sampling voltages within a sampling period, and t is the sampling period; a control module, connected to the calculation module, used to determine whether the voltage change rate is greater than a preset threshold, if the voltage change rate is greater than the preset threshold, generate a first adjustment instruction, if the voltage change rate is less than or equal to the preset threshold, generate a second adjustment instruction, wherein the first adjustment instruction is used to instruct the first voltage conversion circuit to increase the conversion load, and the second adjustment instruction is used to instruct the first voltage conversion circuit to maintain the conversion load.

[0010] Optionally, the circuit further includes: a second voltage conversion circuit, connected between the second output circuit and the second load, and configured to convert the output voltage into the second control voltage.

[0011] Optionally, the second voltage conversion circuit is a DC-DC conversion circuit.

[0012] Optionally, the first load includes: a water pump and an electronic expansion valve, and the second load includes: a wire controller and a built-in driver board for a DC motor.

[0013] According to another embodiment of the present invention, a switching power supply circuit is provided, comprising: a power supply circuit, a transformer, and an output circuit, wherein the primary circuit of the transformer is connected to the power supply circuit, and the secondary circuit is connected to the output circuit, wherein the output circuit comprises the circuit as described in the above embodiment.

[0014] According to yet another embodiment of the present invention, an air conditioner is provided, comprising: the circuit as described in the above embodiment.

[0015] Through the first output circuit, the second output circuit, and the first voltage conversion circuit connected between the first output circuit and the first load of this embodiment, the conversion load can be adjusted according to the voltage change rate of the second load. When the second load changes and causes the voltage of the corresponding circuit to change, the total load of the circuit corresponding to the first load can be flexibly adjusted by adjusting the conversion load of the voltage conversion circuit, thereby maintaining a stable output of the output circuit, solving the technical problem of high cross-regulation rate of multiple output circuits in related technologies, improving the cross-regulation rate of the switching power supply, making the switching power supply work more stably, and ensuring the reliable operation of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0017] Figure 1 is a connection diagram of a secondary output circuit of a transformer according to an embodiment of the present invention;

[0018] Figure 2 is a circuit diagram of an embodiment of the present invention in an implementation scenario;

[0019] Figure 3 4 is a connection diagram of a switching power supply circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and Examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by illustrating examples of the present invention.

[0021] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0022] In this embodiment, a secondary output circuit of a transformer is provided. Figure 1 is a connection diagram of a secondary output circuit of a transformer according to an embodiment of the present invention, such as Figure 1 As shown, the secondary output circuit includes:

[0023] A first output circuit 10 is connected to a first load and is used to output a first control voltage to the first load, wherein the first load is a load with fixed power consumption and is a rated load;

[0024] The second output circuit 12 is connected to the second load and is used to output a second control voltage to the second load, wherein the second load is a load with variable power consumption and is a non-rated load;

[0025] The first output circuit 10 and the second output circuit 12 correspond to two winding outputs of the transformer respectively, and form two feedback loops with the first load and the second load.

[0026] In this embodiment, the first output circuit 10 and the second output circuit 12 are both connected to the secondary circuit of the transformer and draw power from the transformer.

[0027] The first voltage conversion circuit 14 is connected between the first output circuit and the first load, and is used to adjust the conversion load according to the voltage change rate of the second load.

[0028] The conversion load is equivalent to the load of the first voltage conversion circuit 14 itself. Corresponding to its conversion efficiency, the higher the voltage conversion, the smaller the conversion load. Conversely, the lower the voltage conversion efficiency, the larger the conversion load.

[0029] Through the first output circuit, the second output circuit, and the first voltage conversion circuit connected between the first output circuit and the first load of this embodiment, the conversion load can be adjusted according to the voltage change rate of the second load. When the second load changes and causes the voltage of the corresponding circuit to change, the total load of the circuit corresponding to the first load can be flexibly adjusted by adjusting the conversion load of the voltage conversion circuit, thereby maintaining a stable output of the output circuit, solving the technical problem of high cross-regulation rate of multiple output circuits in related technologies, improving the cross-regulation rate of the switching power supply, making the switching power supply work more stably, and ensuring the reliable operation of the unit.

[0030] In one implementation of the present embodiment, the first voltage conversion circuit includes: a first voltage conversion subcircuit, connected between the first output circuit and the first load, for converting the output voltage into a first control voltage based on a first conversion efficiency; a second voltage conversion subcircuit, connected between the first output circuit and the first load, for converting the output voltage into a first control voltage based on a second conversion efficiency, wherein the first conversion efficiency is greater than the second conversion efficiency; a switch circuit, connected to the first voltage conversion subcircuit and the second voltage conversion subcircuit, for adjusting the on-off state of the first voltage conversion subcircuit and the second voltage conversion subcircuit according to the voltage change rate. In one example, the first voltage conversion subcircuit is a DC-DC conversion circuit, and the second voltage conversion subcircuit is a low dropout regulator (LDO), also called a voltage regulator block conversion circuit.

[0031] In another embodiment, the first voltage conversion circuit further includes an external adjustable load (such as a resistor), and the conversion load of the first voltage conversion circuit can be indirectly adjusted by increasing and decreasing the resistance value.

[0032] In this embodiment, the circuit further includes: a voltage sampling circuit connected to the second load, used to collect the voltage value of the second load according to the sampling period; a control chip connected to the voltage sampling circuit and the first voltage conversion circuit, used to calculate the voltage change rate of the second load according to the voltage value, generate an adjustment instruction based on the voltage change rate, and output the adjustment instruction to the first voltage conversion circuit. The control chip can be a main control chip or a circuit control chip.

[0033] In one implementation of the present embodiment, the control chip includes: a calculation module, used to calculate the voltage change rate d of the second load according to the following formula: d = (U12-U11) / t, wherein U11 and U12 are two consecutive sampling voltages within a sampling period, and t is the sampling period; a control module, connected to the calculation module, used to determine whether the voltage change rate is greater than a preset threshold value, if the voltage change rate is greater than the preset threshold value, generate a first adjustment instruction, if the voltage change rate is less than or equal to the preset threshold value, generate a second adjustment instruction, wherein the first adjustment instruction is used to instruct the first voltage conversion circuit to increase the conversion load, and the second adjustment instruction is used to instruct the first voltage conversion circuit to maintain the conversion load.

[0034] In one example, the sampling period t is 1s, U12 and U11 are 12V and 10.8V respectively, and through the formula d=(U12-U11) / t, it can be calculated that d=2.2V / s, which is greater than the preset threshold d0 of 1V / s, so a first adjustment instruction is generated to instruct the first voltage conversion circuit to increase the conversion load.

[0035] In one implementation of this embodiment, the circuit further includes: a second voltage conversion circuit connected between the second output circuit and the second load, and configured to convert the output voltage into a second control voltage. Optionally, the second voltage conversion circuit is a DC-DC conversion circuit.

[0036] According to the circuit application scenario and application equipment of this embodiment, the devices corresponding to the first load and the second load may be different. In one application scenario, it is applied in air-conditioning equipment. The first load includes: water pump, electronic expansion valve, these devices may be activated (turned on) or stopped, corresponding to different load sizes. The second load includes: wire controller, DC motor built-in driver board, these devices will also work stably and have fixed power consumption. In another application scenario, it is applied in a television device. The first load includes: speakers, which adjust the actual power consumption according to the volume. The louder the volume, the greater the power consumption, and the lower the volume, the lower the power consumption. The second load includes: screen, communication interface components, and the power consumption of these devices remains basically unchanged.

[0037] Figure 2 is a circuit diagram of an embodiment of the present invention in an implementation scenario, the output circuit of the switching power supply is as follows Figure 2As shown, the secondary output voltage of the transformer is U1 and U2. U1 is the voltage of the main feedback loop of the switching power supply, which is used to control the action of the main load (water pump, electronic expansion valve, etc.) on the air conditioner. U2 is the voltage of the auxiliary feedback loop of the switching power supply, which is used to control the rated load (wire controller, DC motor built-in driver board, etc.), and the power consumption of this load is basically fixed. A voltage change sampling circuit is added to the main circuit, U11 is the voltage of the main feedback loop voltage U1 before passing through the sampling circuit, and U12 is the voltage after passing through the sampling circuit. The auxiliary feedback loop also includes a rated load voltage conversion circuit, which switches the following two circuits through a switch: ① is a voltage regulator block conversion circuit LDO (low voltage difference linear regulator), which has low efficiency, and ② is a DC-DC conversion circuit, which has high efficiency.

[0038] When the load on the main circuit suddenly becomes heavier, the voltage change rate of the main circuit voltage U1 within unit time t is d=(U12-U11) / t. At this time, the main chip samples this value d and compares it with the threshold d0 set in the MCU, and determines that module 3 uses a DC-DC conversion circuit or a voltage regulator block conversion circuit, thereby improving the output efficiency of the switching power supply.

[0039] In one implementation scenario, the secondary output U1 of the switching power supply is 12V and U2 is 25V, where 12V is the voltage on the main feedback loop of the switching power supply, and 25V requires a power conversion circuit to convert it into 18V to power the wire controller. The power consumption of this wire controller is fixed, and a DC-DC conversion circuit is used by default. When the load of the main loop on the switching power supply increases, the output voltage of the main loop decreases, and the voltage of the other output loop (auxiliary loop) also decreases. The load of the other output needs to be increased to keep the output of the switching power supply stable. When the load on the main circuit suddenly increases, for example, the water pump starts working and the electronic expansion valve suddenly operates, U11 on the voltage sampling circuit is 12V, U12 is 10.8V, and the sampling value d obtained by the MCU within 1s is 220, which is greater than the threshold value d0=100. It is judged that the load on the main circuit has increased and the load of another output needs to be increased. Therefore, the conversion circuit is switched to the voltage regulator conversion circuit to indirectly increase the load on the other output voltage U2. The load can also be increased by adding external resistances. Similarly, when the second load is reduced, the load can also be increased by switching the conversion circuit or adding external resistances, thereby improving the output efficiency of the switching power supply.

[0040] Through the solution of this embodiment, the DC-DC and LDO conversion circuits are flexibly adopted to provide a switching power supply cross-regulation rate, so that the switching power supply can work more stably and ensure the reliable operation of the unit.

[0041] This embodiment also provides a switching power supply circuit, Figure 3 is a connection diagram of a switching power supply circuit according to an embodiment of the present invention. Figure 3As shown, the circuit includes: a power supply circuit 30, a transformer 32, and an output circuit 34, wherein the primary circuit of the transformer is connected to the power supply circuit, and the secondary circuit is connected to the output circuit, wherein the output circuit includes the circuit described in the above embodiment.

[0042] The switching power supply circuit of this embodiment can be applied to various electronic devices including switching power supplies, such as air conditioners, televisions, refrigerators, etc.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A secondary output circuit of a transformer, characterized in that: include: A first output circuit is connected to a first load and is used to output a first control voltage to the first load, wherein the first load is a load with fixed power consumption; A second output circuit is connected to a second load and is used to output a second control voltage to the second load, wherein the second load is a load with variable power consumption; A first voltage conversion circuit, connected between the first output circuit and the first load, for adjusting the conversion load according to the voltage change rate of the second load; a voltage sampling circuit, connected to the second load, and configured to collect a voltage value of the second load according to a sampling period; A control chip is connected to the voltage sampling circuit and the first voltage conversion circuit, and is used to calculate the voltage change rate of the second load according to the voltage value, generate an adjustment instruction based on the voltage change rate, and output the adjustment instruction to the first voltage conversion circuit.

2. The circuit according to claim 1, characterized in that The first voltage conversion circuit comprises: A first voltage conversion subcircuit, connected between the first output circuit and the first load, for converting the output voltage into the first control voltage based on a first conversion efficiency; a second voltage conversion subcircuit, connected between the first output circuit and the first load, and configured to convert the output voltage into the second control voltage based on a second conversion efficiency, wherein the first conversion efficiency is greater than the second conversion efficiency; A switch circuit is connected to the first voltage conversion sub-circuit and the second voltage conversion sub-circuit, and is used to adjust the on-off state of the first voltage conversion sub-circuit and the second voltage conversion sub-circuit according to the voltage change rate.

3. The circuit according to claim 2, characterized in that The first voltage conversion sub-circuit is a DC-DC conversion circuit, and the second voltage conversion sub-circuit is a low dropout linear regulator LDO.

4. The circuit according to claim 1, characterized in that The control chip comprises: A calculation module, used to calculate the voltage change rate d of the second load according to the following formula: d=(U12-U11) / t, wherein U11 and U12 are two consecutive sampled voltages in one sampling period, and t is the sampling period; A control module is connected to the calculation module and is used to determine whether the voltage change rate is greater than a preset threshold value. If the voltage change rate is greater than the preset threshold value, a first adjustment instruction is generated; if the voltage change rate is less than or equal to the preset threshold value, a second adjustment instruction is generated, wherein the first adjustment instruction is used to instruct the first voltage conversion circuit to increase the conversion load, and the second adjustment instruction is used to instruct the first voltage conversion circuit to maintain the conversion load.

5. The circuit according to claim 1, characterized in that The circuit further comprises: The second voltage conversion circuit is connected between the second output circuit and the second load, and is used for converting the output voltage into the second control voltage.

6. The circuit according to claim 5, characterized in that The second voltage conversion circuit is a DC-DC conversion circuit.

7. The circuit according to claim 1, characterized in that The first load includes: a water pump and an electronic expansion valve, and the second load includes: a wire controller and a built-in driver board for a DC motor.

8. A switching power supply circuit, characterized in that: include: A power supply circuit, a transformer, and an output circuit, wherein the primary circuit of the transformer is connected to the power supply circuit, and the secondary circuit is connected to the output circuit, wherein the output circuit comprises the circuit as claimed in any one of claims 1 to 7.

9. An air conditioner, characterized in that: include: The switching power supply circuit as claimed in claim 8.

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