Handheld variable-voltage variable-frequency test power supply

Abstract

The invention provides a handheld variable-voltage variable-frequency test power supply which comprises a lithium battery pack, a variable-voltage variable-frequency module, a control module, a first voltage transformer and a second voltage transformer. The lithium battery pack is connected in series with the variable-voltage variable-frequency module; the control module is connected between the lithium battery pack and the voltage input end of the voltage transformation and frequency conversion module through a first voltage transformer, is connected with the voltage output end of the voltage transformation and frequency conversion module through a second voltage transformer, and is also connected with the control end of the voltage transformation and frequency conversion module. The lithium battery pack provides direct-current voltage; the control module generates a first control instruction used for adjusting the actual input and output alternating voltage and frequency of the voltage transformation and frequency conversion module. The variable-voltage variable-frequency module converts direct-current voltage provided by the lithium battery pack into alternating-current voltage and adjusts actual output alternating-current voltage and frequency to preset target alternating-current voltage and preset frequency according to the first control instruction. According to the invention, high-precision adjustment of voltage and frequency can be realized, and advantages of portability, high efficiency and the like are realized.

Description

Technical Field

[0001] The invention relates to the technical field of power systems, and in particular to a handheld voltage- and frequency-converting test power supply. Background Art

[0002] Variable frequency power supplies are widely used in industrial production, scientific research and experiments, etc. At present, variable frequency power supplies on the market are usually powered by single-phase or three-phase AC power, and after rectification, buffering, inversion, filtering and other links, high-voltage AC output is obtained. The adjustment range of output voltage and frequency is limited, which cannot meet the requirements of test equipment for high precision, adjustable voltage and adjustable frequency, especially the needs of handheld testing.

[0003] Therefore, there is an urgent need for a handheld variable voltage and variable frequency test power supply that can achieve high-precision regulation of voltage and frequency and has the advantages of portability and high efficiency. Summary of the invention

[0004] The technical problem to be solved by the embodiments of the present invention is to provide a handheld variable voltage and variable frequency test power supply, which can achieve high-precision adjustment of voltage and frequency and has the advantages of portability and high efficiency.

[0005] In order to solve the above technical problems, the embodiment of the present invention provides a handheld variable voltage and frequency conversion test power supply, including a lithium battery pack, a variable voltage and frequency conversion module, a control module, a first voltage transformer and a second voltage transformer; wherein,

[0006] The lithium battery pack is connected in series with the voltage and frequency conversion module to form a power supply circuit;

[0007] The control module is connected between the lithium battery pack and the voltage input terminal of the voltage conversion module through the first voltage transformer, and is connected to the voltage output terminal of the voltage conversion module through the second voltage transformer, and the control module is also connected to the control terminal of the voltage conversion module;

[0008] Wherein, the lithium battery pack is used to provide a DC voltage;

[0009] The control module is used to generate a first control instruction output to the voltage-conversion module based on a preset target AC voltage and a preset frequency, and in combination with an actual input DC voltage of the voltage-conversion module collected by the first voltage transformer and an actual output AC voltage of the voltage-conversion module collected by the second voltage transformer, so as to perform closed-loop control on the input and output voltages of the voltage-conversion module and adjust the frequency thereof until the final output AC voltage of the voltage-conversion module is the preset target AC voltage and the frequency is the preset frequency;

[0010] The voltage and frequency conversion module is used to convert the DC voltage provided by the lithium battery pack into an AC voltage, and according to the first control instruction issued by the control module, the converted AC voltage is finally adjusted to the preset target AC voltage and the frequency is the preset frequency.

[0011] Among them, it also includes: an isolated adjustable boost module and a third voltage transformer; among them,

[0012] The isolated adjustable boost module is arranged between the lithium battery pack and the voltage input terminal of the voltage and frequency conversion module;

[0013] The control module is connected between the lithium battery pack and the voltage input terminal of the isolated adjustable boost module through the third voltage transformer, and is connected between the voltage output terminal of the isolated adjustable boost module and the voltage input terminal of the voltage and frequency conversion module through the first voltage transformer, and the control module is also connected to the control terminal of the isolated adjustable boost module;

[0014] The control module is further used to obtain the actual input DC voltage corresponding to the preset target AC voltage finally output by the voltage and frequency conversion module and the frequency is the preset frequency, and set the obtained actual input DC voltage as the target output expected voltage of the isolated adjustable boost module, and further combine the actual input DC voltage of the isolated adjustable boost module collected by the third voltage transformer and the actual output DC voltage of the isolated adjustable boost module collected by the first voltage transformer to generate a second control instruction output to the isolated adjustable boost module, so as to perform closed-loop control on the actual input DC voltage, the actual output DC voltage and the target output expected voltage of the isolated adjustable boost module until the final output DC voltage of the isolated adjustable boost module is the target output expected voltage;

[0015] The isolated adjustable boost module is used to boost the DC voltage provided by the lithium battery pack, and finally adjust the boosted output DC voltage to the target output expected voltage according to the second control instruction issued by the control module.

[0016] Among them, it also includes: a multi-stage low-pass filter module and a fourth voltage transformer; wherein,

[0017] The voltage input end of the multi-stage low-pass filter module is connected to the voltage output end of the voltage conversion and frequency conversion module; the multi-stage low-pass filter module is used to perform multiple low-pass filtering processes on the output voltage of the voltage conversion and frequency conversion module;

[0018] The control module is connected to the voltage output end of the multi-stage low-pass filtering module through the fourth voltage transformer, and is connected between the voltage output end of the voltage conversion and frequency conversion module and the voltage input end of the multi-stage low-pass filtering module through the second voltage transformer; the control module is also used to monitor the output voltage of the multi-stage low-pass filtering module after low-pass filtering collected by the fourth voltage transformer.

[0019] Among them, it also includes: a bypass switch; among them,

[0020] The bypass switch is connected in parallel to the two ends of the isolated adjustable boost module, and is used to conduct or cut off the power supply circuit directly connected between the lithium battery pack and the voltage and frequency conversion module.

[0021] The lithium battery pack is composed of a power battery pack, a balancing and protection circuit and a power monitoring circuit.

[0022] The voltage-frequency conversion module is a full-bridge control loop composed of four MOSFET field-effect transistors.

[0023] Wherein, the isolated adjustable boost module is a push-pull type isolated switch power supply circuit.

[0024] Implementing the embodiments of the present invention has the following beneficial effects:

[0025] 1. The present invention provides a DC voltage through a lithium battery pack, and a control module generates a first control instruction for adjusting the actual input and output AC voltage and frequency of the voltage and frequency conversion module, so that the voltage and frequency conversion module adjusts the actual output AC voltage and frequency to a preset target AC voltage and preset frequency according to the first control instruction when converting the DC voltage provided by the lithium battery pack into an AC voltage, thereby achieving high-precision regulation of voltage and frequency, and having the advantages of portability and high efficiency;

[0026] 2. The present invention generates a second control instruction through a control module for closed-loop control of the actual input DC voltage, the actual output DC voltage and the target output desired voltage of the isolated adjustable boost module, so that the isolated adjustable boost module modulates the output target output desired voltage according to the second control instruction after boosting the DC voltage provided by the lithium battery pack, thereby improving the purity of the output waveform and the ability to output peak current. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying creative labor, other drawings obtained based on these drawings still belong to the scope of the present invention.

[0028] Figure 1 A connection structure diagram of a handheld variable voltage and variable frequency test power supply in an embodiment of the present invention;

[0029] Figure 2 A circuit connection diagram of a voltage-frequency conversion module in a handheld voltage-frequency conversion test power supply in an embodiment of the present invention;

[0030] Figure 3 It is a connection structure diagram of another handheld variable voltage and variable frequency test power supply in an embodiment of the present invention;

[0031] Figure 4 The present invention is a circuit connection diagram of an isolated adjustable boost module in another handheld variable voltage and variable frequency test power supply in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0033] like Figure 1 As shown in the figure, a handheld voltage-frequency conversion test power supply is proposed in an embodiment of the present invention, comprising a lithium battery pack 1, a voltage-frequency conversion module 2, a control module 3, a first voltage transformer 4 and a second voltage transformer 5; wherein,

[0034] The lithium battery pack 1 and the voltage and frequency conversion module 2 are connected in series to form a power supply circuit; wherein the lithium battery pack 1 is used to provide a DC voltage;

[0035] The control module 3 is connected between the lithium battery pack 1 and the voltage input end of the voltage conversion module 2 through the first voltage transformer 4, and is connected to the voltage output end of the voltage conversion module 2 through the second voltage transformer 5, and the control module 3 is also connected to the control end of the voltage conversion module 2; wherein, the control module 3 is used to generate an output to the voltage conversion module 2 based on the preset target AC voltage and preset frequency input by the user, and in combination with the actual input DC voltage of the voltage conversion module 2 collected through the first voltage transformer 4 and the actual output AC voltage of the voltage conversion module 2 collected through the second voltage transformer 5. The first control instruction of module 2 is used to perform closed-loop control on the input and output voltages of the voltage conversion module 2 and adjust its frequency until the final output AC voltage of the voltage conversion module 2 is the preset target AC voltage and the frequency is the preset frequency; it should be noted that the control module 3 uses the PID closed-loop control algorithm commonly used in the art to dynamically adjust the actual input DC voltage and the actual output AC voltage at both ends of the voltage conversion module 2, which will not be repeated here; the frequency adjustment can be achieved by adjusting the duty cycle of the voltage waveform, which is a commonly used technical means in the art and will not be repeated here;

[0036] The voltage and frequency conversion module 2 is used to convert the DC voltage provided by the lithium battery pack 1 into an AC voltage, and according to the first control instruction issued by the control module 3, the converted AC voltage is finally adjusted to a preset target AC voltage and a preset frequency.

[0037] It is understandable that the lithium battery pack 1 is composed of a power battery pack, a balancing and protection circuit, and a power monitoring circuit. The specific structure and connection relationship are achieved by using common technical means in this field, which will not be described in detail here.

[0038] The voltage and frequency conversion module 2 is a full-bridge control circuit composed of four MOSFET field effect tubes. For details, please refer to Figure 2 shown. Figure 2 In the figure, the full-bridge control loop is the main component of the power output part of the voltage and frequency conversion module. The relevant PWM waveform diagram shows the idea of ​​the management unit controlling the four MOSFET field-effect tubes to achieve AC waveform output. The specific principle is the control principle of the power output part of the traditional inverter power supply, which will not be repeated here.

[0039] The control module 3 is composed of a DSP chip and its peripheral circuits. The specific structure and connection relationship are realized by using common technical means in this field, which will not be described in detail here.

[0040] like Figure 3 As shown, another handheld voltage-variable frequency conversion test power supply proposed in an embodiment of the present invention includes a lithium battery pack 1, a voltage-variable frequency conversion module 2, a control module 3, an isolated adjustable boost module 6, a multi-stage low-pass filter module 8, a first voltage transformer 4, a second voltage transformer 5, a third voltage transformer 7, a fourth voltage transformer 9 and a bypass switch 10; wherein,

[0041] The lithium battery pack 1 is connected in series with the isolated adjustable boost module 6, the voltage and frequency conversion module 2 and the multi-stage low-pass filter module 8 in sequence to form a power supply circuit;

[0042] The control module 3 is connected between the lithium battery pack 1 and the voltage input end of the isolated adjustable boost module 6 through the third voltage transformer 7, is connected between the voltage output end of the isolated adjustable boost module 6 and the voltage input end of the voltage conversion module 2 through the first voltage transformer 4, is connected between the voltage output end of the voltage conversion module 2 and the input end of the multi-stage low-pass filter module 8 through the second voltage transformer 5, and is connected to the output end of the multi-stage low-pass filter module 8 through the fourth voltage transformer 9, and the control module 3 is also connected to the control end of the voltage conversion module 2 and the control end of the isolated adjustable boost module 6;

[0043] The bypass switch 10 is connected in parallel to both ends of the isolated adjustable boost module 6;

[0044] Wherein, the lithium battery pack 1 is used to provide a DC voltage;

[0045] The control module 3 is used to generate a first control instruction output to the voltage conversion module 2 based on the preset target AC voltage and preset frequency input by the user, and in combination with the actual input DC voltage collected by the first voltage transformer 4 to the voltage conversion module 2 and the actual output AC voltage collected by the second voltage transformer 5 to the voltage conversion module 2, so as to perform closed-loop control on the input and output voltages of the voltage conversion module 2 and adjust its frequency until the final output AC voltage of the voltage conversion module 2 is the preset target AC voltage and the frequency is the preset frequency; the control module 3 is also used to obtain the actual input DC voltage corresponding to the final output of the preset target AC voltage and the frequency being the preset frequency collected by the first voltage transformer 4 to the voltage conversion module 2, and to output the actual input DC voltage to the voltage conversion module 2. The DC voltage is set to the target output expected voltage of the isolated adjustable boost module 6, and further combined with the actual input DC voltage of the isolated adjustable boost module 6 (i.e., the output voltage of the lithium battery pack 1) collected by the third voltage transformer 7 and the actual output DC voltage of the isolated adjustable boost module 6 collected by the first voltage transformer 4, a second control instruction output to the isolated adjustable boost module 6 is generated to perform closed-loop control on the actual input DC voltage, the actual output DC voltage and the target output expected voltage of the isolated adjustable boost module 6 until the final output DC voltage of the isolated adjustable boost module 6 is the target output expected voltage; the control module 3 is also used to monitor the output voltage collected by the fourth voltage transformer 9 from the multi-stage low-pass filtering module 8 after low-pass filtering;

[0046] The isolated adjustable boost module 6 is used to boost the DC voltage provided by the lithium battery pack 1, and finally adjust the boosted output DC voltage to the target output desired voltage according to the second control instruction issued by the control module 3;

[0047] The voltage-frequency conversion module 2 is used to convert the target output desired voltage output by the isolated adjustable boost module 6 into an AC voltage, and according to the first control instruction issued by the control module 3, the converted output AC voltage is finally adjusted to a preset target AC voltage and a preset frequency;

[0048] The bypass switch 10 is used to conduct or cut off the power supply circuit directly connected between the lithium battery pack 1 and the voltage and frequency conversion module 2, so as to provide energy for low-voltage and high-current applications.

[0049] It is understandable that the lithium battery pack 1 is composed of a power battery pack, a balancing and protection circuit, and a power monitoring circuit. The specific structure and connection relationship are achieved by using common technical means in this field, which will not be described in detail here.

[0050] The voltage and frequency conversion module 2 is a full-bridge control circuit composed of four MOSFET field effect tubes. For details, please refer to the above Figure 2 shown. Figure 2 In the figure, the full-bridge control loop is the main component of the power output part of the voltage and frequency conversion module. The relevant PWM waveform diagram shows the idea of ​​the management unit controlling the four MOSFET field-effect tubes to achieve AC waveform output. The specific principle is the control principle of the power output part of the traditional inverter power supply, which will not be repeated here.

[0051] The control module 3 is composed of a DSP chip and its peripheral circuits. The specific structure and connection relationship are realized by using common technical means in this field, which will not be described in detail here.

[0052] The isolated adjustable boost module 6 is a push-pull isolated switch power supply circuit, see Figure 4 As shown. Figure 4 Compared with the traditional power supply control unit which is a dedicated PWM control chip, here it is replaced by a management unit plus a drive interface circuit. The relevant control loop is implemented by the software algorithm in the management unit, which is achieved through common technical means in this field and will not be repeated here.

[0053] Implementing the embodiments of the present invention has the following beneficial effects:

[0054] 1. The present invention provides a DC voltage through a lithium battery pack, and a control module generates a first control instruction for adjusting the actual input and output AC voltage and frequency of the voltage and frequency conversion module, so that the voltage and frequency conversion module adjusts the actual output AC voltage and frequency to a preset target AC voltage and preset frequency according to the first control instruction when converting the DC voltage provided by the lithium battery pack into an AC voltage, thereby achieving high-precision regulation of voltage and frequency, and having the advantages of portability and high efficiency;

[0055] 2. The present invention generates a second control instruction through a control module for closed-loop control of the actual input DC voltage, the actual output DC voltage and the target output desired voltage of the isolated adjustable boost module, so that the isolated adjustable boost module modulates the output target output desired voltage according to the second control instruction after boosting the DC voltage provided by the lithium battery pack, thereby improving the purity of the output waveform and the ability to output peak current.

[0056] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A handheld variable voltage and variable frequency test power supply, characterized in that: It includes a lithium battery pack, a voltage and frequency conversion module, a control module, a first voltage transformer and a second voltage transformer; wherein, The lithium battery pack is connected in series with the voltage and frequency conversion module to form a power supply circuit; The control module is connected between the lithium battery pack and the voltage input terminal of the voltage conversion module through the first voltage transformer, and is connected to the voltage output terminal of the voltage conversion module through the second voltage transformer, and the control module is also connected to the control terminal of the voltage conversion module; Wherein, the lithium battery pack is used to provide a DC voltage; The control module is used to generate a first control instruction output to the voltage-conversion module based on a preset target AC voltage and a preset frequency, and in combination with an actual input DC voltage of the voltage-conversion module collected by the first voltage transformer and an actual output AC voltage of the voltage-conversion module collected by the second voltage transformer, so as to perform closed-loop control on the input and output voltages of the voltage-conversion module and adjust the frequency thereof until the final output AC voltage of the voltage-conversion module is the preset target AC voltage and the frequency is the preset frequency; The voltage and frequency conversion module is used to convert the DC voltage provided by the lithium battery pack into an AC voltage, and according to the first control instruction issued by the control module, the converted AC voltage is finally adjusted to the preset target AC voltage and the frequency is the preset frequency.

2. The handheld variable voltage and variable frequency test power supply according to claim 1, characterized in that: Also includes: Isolate the adjustable boost module and the third voltage transformer; wherein, The isolated adjustable boost module is arranged between the lithium battery pack and the voltage input terminal of the voltage and frequency conversion module; The control module is connected between the lithium battery pack and the voltage input terminal of the isolated adjustable boost module through the third voltage transformer, and is connected between the voltage output terminal of the isolated adjustable boost module and the voltage input terminal of the voltage and frequency conversion module through the first voltage transformer, and the control module is also connected to the control terminal of the isolated adjustable boost module; The control module is further used to obtain the actual input DC voltage corresponding to the preset target AC voltage finally output by the voltage and frequency conversion module and the frequency is the preset frequency, and set the obtained actual input DC voltage as the target output expected voltage of the isolated adjustable boost module, and further combine the actual input DC voltage of the isolated adjustable boost module collected by the third voltage transformer and the actual output DC voltage of the isolated adjustable boost module collected by the first voltage transformer to generate a second control instruction output to the isolated adjustable boost module, so as to perform closed-loop control on the actual input DC voltage, the actual output DC voltage and the target output expected voltage of the isolated adjustable boost module until the final output DC voltage of the isolated adjustable boost module is the target output expected voltage; The isolated adjustable boost module is used to boost the DC voltage provided by the lithium battery pack, and finally adjust the boosted output DC voltage to the target output desired voltage according to the second control instruction issued by the control module.

3. The handheld variable voltage and variable frequency test power supply as claimed in claim 2, characterized in that: Also includes: A multi-stage low-pass filter module and a fourth voltage transformer; wherein, The voltage input end of the multi-stage low-pass filter module is connected to the voltage output end of the voltage conversion and frequency conversion module; the multi-stage low-pass filter module is used to perform multiple low-pass filtering processes on the output voltage of the voltage conversion and frequency conversion module; The control module is connected to the voltage output end of the multi-stage low-pass filtering module through the fourth voltage transformer, and is connected between the voltage output end of the voltage conversion and frequency conversion module and the voltage input end of the multi-stage low-pass filtering module through the second voltage transformer; the control module is also used to monitor the output voltage of the multi-stage low-pass filtering module after low-pass filtering collected by the fourth voltage transformer.

4. The handheld variable voltage and variable frequency test power supply as claimed in claim 3, characterized in that: Also includes: a bypass switch; wherein, The bypass switch is connected in parallel to the two ends of the isolated adjustable boost module, and is used to conduct or cut off the power supply circuit directly connected between the lithium battery pack and the voltage and frequency conversion module.

5. The handheld variable voltage and variable frequency test power supply as claimed in claim 4, characterized in that: The lithium battery pack is composed of a power battery pack, a balancing and protection circuit and a power monitoring circuit.

6. The handheld variable voltage and variable frequency test power supply as claimed in claim 5, characterized in that: The voltage-frequency conversion module is a full-bridge control loop composed of four MOSFET field-effect transistors.

7. The handheld variable voltage and variable frequency test power supply as claimed in claim 6, characterized in that: The isolated adjustable boost module is a push-pull type isolated switch power supply circuit.

Images