A power amplifier

Abstract

The invention discloses a power amplifier, which is applied in the field of vibration table driving. The technical scheme of the power amplifier is as follows: the power amplifier comprises a power input end, the output of the power input end is respectively connected with an excitation voltage regulating circuit and a power module rectifier circuit, the output of the power module rectifier circuit is connected with a plurality of high-voltage power module boxes; the high-voltage power module box comprises a plurality of IGBT modules, each IGBT module is connected with a current detection circuit for real-time acquisition of its output current, and the current detection circuit is connected with a controller input inside the high-voltage power module box; the technical effect is as follows: the output current of the IGBT module can be acquired in real time, and when the output current deviation of a certain IGBT is large, the control circuit can be dynamically adjusted according to an algorithm to ensure that each IGBT module is balanced during normal operation; when the IGBT output current exceeds a normal value, the internal control system of the power module box starts protection and outputs the fault to the power amplifier control unit.

Description

Technical Field

[0001] The invention relates to the field of vibration table driving, and in particular to a power amplifier. Background Art

[0002] At present, with the rapid development of my country's heavy industry, more and more large-scale equipment requires high-power vibration tables for quality testing. Therefore, power amplifiers are indispensable in the use of vibration tables.

[0003] Most of the power amplifiers traditionally used in vibration tables use transformers to perform high-voltage isolation control on the power supply. Since the power of the vibration table is directly output by multiple power module boxes, a transformer has to be installed in each power module box, which greatly occupies the internal space of the power module box and increases the equipment cost. At the same time, since the traditional power amplifier has transformer control, there is no real-time current collection of the IGBT module in its power module box. When the external load suddenly increases or other complex situations occur, the output current of the IGBT will be at risk of breakdown after the sudden increase, and the upcoming current spike cannot be predicted. Summary of the invention

[0004] The purpose of the present invention is to provide a power amplifier, which has the advantage of being able to predict the upcoming peak current of an IGBT module to ensure that the current will not break down the IGBT module.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions:

[0006] A power amplifier, comprising a power input terminal, wherein the output of the power input terminal is respectively connected to an excitation voltage regulating circuit and a power module rectifier circuit, wherein the output of the power module rectifier circuit is connected to a plurality of high-voltage power module boxes; the high-voltage power module box comprises a plurality of IGBT modules, wherein each IGBT module is connected to a current detection circuit for real-time acquisition of its output current, and the current detection circuit is connected to a controller input inside the high-voltage power module box.

[0007] Through the above technical solution: the external AC power supply voltage is directly distributed to the excitation voltage regulation circuit and the power module rectifier circuit respectively; the power module rectifier circuit rectifies the voltage and inputs it into the high-voltage power module box; when the IGBT module connected to the output end of the power module rectifier circuit is turned on, the current required for its conduction, and the current detection circuit connected to the IGBT can collect its current current size in real time; when the output current deviation of a certain IGBT is large, the control circuit is dynamically adjusted according to the algorithm to ensure that each IGBT module is balanced during normal operation.

[0008] The present invention is further configured as follows: the current detection circuit includes a current sensor, the current sensor input is connected to a first differential amplifier circuit, the output end of the first differential amplifier circuit is connected to a second differential amplifier circuit, the output end and input end of the second differential amplifier circuit are connected in parallel with a double diode, the output end input of the second differential amplifier circuit is provided with an operational amplifier chip, the output of the operational amplifier chip is connected to a sensor amplification and AD conversion circuit, and the output of the AD conversion circuit is connected to a controller inside a high-voltage power module box.

[0009] Through the above technical solution: the double diodes limit the voltage of the second differential circuit, which can prevent excessive voltage from damaging the back-end components and avoid inaccurate current collection caused by distortion of the amplifier circuit. The operational amplifier chip transmits the real-time collected current signal to the controller after conversion by the AD conversion circuit. The controller can determine whether the current IGBT module is working normally based on the read current size.

[0010] The present invention is further configured such that after the multiple IGBT modules pass through the current detection circuit, if the controller detects that the currents thereof are normal, the controller drives the output.

[0011] Through the above technical solution: during the working process, when the IGBT module is turned on, the current inside it is in the on state. Since the external load will change, it may cause an increase in instantaneous current. When the IGBT output current exceeds the normal value, the internal control system of the power module box starts protection and outputs the fault to the power amplifier control unit.

[0012] The present invention is further configured as follows: the excitation voltage regulation circuit adopts a three-phase thyristor circuit, which can perform stepless regulation on the excitation voltage.

[0013] Through the above technical solution: the three-phase thyristor circuit can adjust the excitation voltage steplessly according to the external load demand, without the need to significantly increase or decrease the voltage internally many times, which can effectively reduce energy loss.

[0014] The present invention is further configured such that: the output of the excitation voltage regulating circuit is connected to an excitation rectifying circuit and outputs the excitation.

[0015] Through the above technical solution: the excitation rectifier circuit rectifies the input voltage into unidirectional pulse direct current.

[0016] The present invention is further configured as follows: the output of the power amplifier consists of an excitation output and a drive output, the excitation output power accounts for 20% of the total output, and the drive output accounts for 80% of the total output.

[0017] Through the above technical solution: when adjusting according to the power required by the external load, it is only necessary to adjust the voltage of 20% of the excitation output to complete the power adjustment.

[0018] The present invention is further configured such that the component installation density in the high-voltage power module box is reduced, which helps to dissipate heat when the power increases.

[0019] Through the above technical solution: since the power input end is directly connected to the excitation voltage regulation circuit and the power module rectification circuit, a transformerless method is adopted, which can increase the free space in the high-voltage power module box, so the installation space of the electrical components is increased, which is conducive to heat dissipation, can reduce the probability of failure during operation, and extend the service life of the electrical components.

[0020] The present invention is further configured such that: the power input end is powered by an industrial power supply of 380VAC / 50HZ.

[0021] Through the above technical solution: 380V / 50HZ industrial power supply is relatively easy to obtain, the components of power conversion can be omitted, and the cost can be effectively reduced.

[0022] In summary, the present invention has the following beneficial effects:

[0023] By connecting a current detection circuit to each IGBT module, the output current of the IGBT module can be collected in real time. When the output current deviation of a certain IGBT is large, the control circuit can be dynamically adjusted according to the algorithm to ensure that each IGBT module is balanced during normal operation. When the IGBT output current exceeds the normal value, the internal control system of the power module box starts protection and outputs the fault to the power amplifier control unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a system block diagram of a power amplifier according to the present embodiment;

[0025] Figure 2 is a block diagram of the high voltage power module box system of this embodiment;

[0026] Figure 3 Schematic diagram of the current detection circuit of this embodiment. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0028] Example:

[0029] refer to Figure 1 and Figure 2A power amplifier includes a power input end, the power input end is powered by a 380VAC / 50HZ industrial power supply, the power supply is easy to obtain and does not require additional conversion equipment. The power input end is directly connected to an excitation voltage regulation circuit and a power module rectifier circuit, eliminating the transformer used in the front end of a traditional power amplifier. The output connection of the power module rectifier circuit is provided with multiple high-voltage power module boxes, the high-voltage power module box includes multiple IGBT modules, each IGBT module is connected to a current detection circuit for real-time acquisition of its output current, the current detection circuit is connected to the controller input inside the high-voltage power module box, and the current detection circuit connected to the IGBT can collect the current output current in real time. When the output current deviation of a certain IGBT is large, the controller is dynamically adjusted according to the algorithm to ensure that each IGBT module is balanced during normal operation. When the IGBT output current exceeds the normal value, the internal control system of the power module box starts protection and outputs the fault to the power amplifier control unit. The control unit controls the device to shut down and report an error.

[0030] refer to Figure 1 The output of the power amplifier consists of excitation output and drive output. The excitation output power accounts for 20% of the total output, and the drive output accounts for 80% of the total output. The excitation voltage regulation circuit adopts a three-phase thyristor circuit, which can adjust the excitation voltage steplessly. When adjusting according to the power required by the external load, only 20% of the excitation output voltage needs to be adjusted to complete the power regulation. The output of the excitation voltage regulation circuit is connected to the excitation rectifier circuit and excitation output.

[0031] refer to Figure 2 and Figure 3 The current detection circuit includes a current sensor, the current sensor input is connected to a first differential amplifier circuit, the output end of the first differential amplifier circuit is connected to a second differential amplifier circuit, the output end of the second differential amplifier circuit is connected to a double diode in parallel with the input end, the double diode can limit the voltage of the second differential circuit, which can avoid excessive voltage and damage to the back-end components, and avoid inaccurate current collection caused by distortion of the amplifier circuit. The output end input of the second differential amplifier circuit is provided with an operational amplifier chip, the operational amplifier chip transmits the real-time collected current signal to the controller after being converted by the AD conversion circuit, and drives the output if the controller detects that the current is normal. The controller can judge whether the current IGBT module is working normally according to the read current size.

[0032] refer to Figure 1 The component installation density in the high-voltage power module box is reduced, which helps to dissipate heat when the power increases, reduces the probability of electrical component failure during operation, and extends the service life of electrical components.

[0033] In summary, the working process and principle of this embodiment are as follows:

[0034] When performing power amplification, a 380V AC power supply is input, and the excitation voltage regulation circuit and the power module rectifier circuit are powered in a ratio of 2:8. The excitation voltage is output after excitation rectification. When adjusting according to the power required by the external load, only 20% of the excitation output needs to be regulated to complete the power adjustment. The voltage supplied to the power module rectifier circuit is rectified and input into the high-voltage power module box. The IGBT module outputs current after being turned on. The current detection circuit connected to the IGBT module collects the output current in real time. The controller in the power module box compares and calculates the collected current according to the algorithm. When the output current deviation of a certain IGBT is large, the control circuit is dynamically adjusted according to the algorithm to ensure that each IGBT module is balanced during normal operation. When the IGBT output current exceeds the normal value, the internal control system of the power module box starts protection and outputs the fault to the power amplifier control unit, thereby realizing overcurrent protection of the power amplifier. After the IGBT module works normally, it can be driven and output externally.

[0035] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A power amplifier used in a vibration table. It is characterized in that The power amplifier comprises a power input terminal, the output of which is respectively connected to an excitation voltage regulating circuit and a power module rectifier circuit, and the output of the power module rectifier circuit is connected to a plurality of high-voltage power module boxes; The high-voltage power module box includes a plurality of IGBT modules, each of which is connected to a current detection circuit for real-time acquisition of its output current, and the current detection circuit is connected to the controller input inside the high-voltage power module box; The current detection circuit includes a current sensor, the current sensor input is connected to a first differential amplifier circuit, the output end of the first differential amplifier circuit is connected to a second differential amplifier circuit, the output end and the input end of the second differential amplifier circuit are connected in parallel with a double diode, the output end input of the second differential amplifier circuit is provided with an operational amplifier chip, the output of the operational amplifier chip is connected to a sensor amplifier circuit and an AD conversion circuit, and the output of the AD conversion circuit is connected to a controller inside the high-voltage power module box; After the multiple IGBT modules pass through the current detection circuit, if the controller detects that the current is normal, the controller drives the output; The excitation voltage regulation circuit adopts a three-phase thyristor circuit to perform stepless regulation on the excitation voltage; The output of the excitation voltage regulating circuit is connected to an excitation rectifier circuit and outputs an excitation; The output of the power amplifier consists of an excitation output and a drive output, wherein the excitation output power accounts for 20% of the total output, and the drive output accounts for 80% of the total output.

2. A power amplifier according to claim 1, characterized in that: The component mounting density in the high-voltage power module box is reduced, which helps to dissipate heat when the power increases.

3. A power amplifier according to claim 1, characterized in that: The power input end is powered by a 380VAC / 50HZ industrial power supply.

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