CN111162741B - Digital power amplifier and matched filtering method - Google Patents
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- H—ELECTRICITY
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- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
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- H03F3/24—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers of transmitter output stages
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Abstract
The invention provides a digital power amplifier and a matched filtering method, which comprises the following steps: the device comprises a signal preprocessing unit, a power amplification unit, a control unit, an input signal unit and a filtering unit; one end of the signal preprocessing unit is connected with the input signal unit; the signal preprocessing unit can perform pulse width modulation and dead zone control on an input signal; one end of the power amplification unit is connected with the signal preprocessing unit, and the power amplification unit can amplify the PWM signal output by the signal preprocessing unit; the control unit is connected with the signal preprocessing unit and the power amplification unit, and can realize state detection and protection control of the power amplification unit; the filtering unit can realize impedance matching between the power amplification unit and the load. The invention can enable the digital power amplifier to be arranged in a small cylindrical aluminum cylinder for a towing line array through an integrated and modularized design.
Description
Technical Field
The invention relates to the field of electronic technology application, in particular to a digital power amplifier suitable for actively towing a transmitting line array and a matched filtering method.
Background
The traditional power amplifier comprises A class, B class, AB class and C class. These types of amplifiers all belong to linear amplifiers, and the input analog signal is directly amplified linearly, so that nonlinear distortion is small. However, these types of amplifiers operate in linear amplification regions, so that the internal transistors consume a significant portion of the power when operating, and even in static operation, the transistors consume some power, which greatly limits the efficiency of the power amplifier. The concept of class D amplifier was proposed by Baxandall in 1959, and compared with A, B, AB and class C class isopower amplifiers, the class D amplifier has the characteristics that: the output stage MOS tube works in a switching state, so that the efficiency is high, and the energy utilization rate is improved to more than 90% from the traditional 50%; and secondly, the class D power amplifier can greatly reduce the size of a transmitter and save the cost. In recent years, the development of electronic technology greatly improves the switching frequency of the MOS transistor, and the conduction loss is reduced greatly, so that the D-type power amplifier can achieve the performance of analog power amplification on the premise of ensuring high efficiency, and is widely applied to consumer electronics and professional audio products. In the application of towing the transmitting line array, the general D-type power amplifier cannot meet the use requirement due to the conditions of huge system, complex structure, special load and the like. Firstly, the traditional D-type power amplifier is only suitable for driving pure resistive loads such as a loudspeaker, and the load in the towing transmitting line array is a transmitting transducer, the transmitting transducer is a capacitive load, the impedance of the transmitting transducer changes along with the change of frequency, and the peak is easily generated at the output end of the power amplifier, so that a power tube is damaged; secondly, the traditional D-type power amplifier has no negative feedback, so that the signal distortion rate is high easily, and the electromagnetic radiation problem is caused. In addition, the traditional D-type power amplifier has single function and does not have interaction capability with external equipment, and in view of the fact that the towed transmitting line array is in a towed state when working, the power amplifier must have a self-checking function, and the working state of the power amplifier can be monitored in real time.
Patent document CN110463034a discloses a digital power amplifier, which belongs to the field of power amplifiers, and comprises: a first DSM, a second DSM, a first PWM, a second PWM, a low pass filter, a digital up converter, a comb filter, and a power amplifier; the first PWM is coupled with the first DSM, is used for modulating the first DSM to input a first DSM signal and outputting a first PWM signal; the second PWM is coupled with the second DSM, is used for modulating a second DSM signal input by the second DSM, and outputs a second PWM signal; the low-pass filter is coupled with the first PWM and the second PWM respectively; the digital up-converter is coupled with the low-pass filter and is used for modulating the first PWM signal after low-pass filtering and the second PWM signal after low-pass filtering and outputting a third PWM signal with preset radio frequency; the comb filter is coupled with the digital up-converter and used for inhibiting PWM harmonic waves of the third PWM signal; the power amplifier is coupled with the comb filter and is used for carrying out power amplification processing on the third PWM signal after harmonic suppression. This patent is not well suited for use in actively towed transmit line arrays.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a digital power amplifier and a matched filtering method.
According to the present invention there is provided a digital power amplifier adapted for actively towing an array of transmit lines, comprising: the device comprises a signal preprocessing unit, a power amplification unit, a control unit, an input signal unit and a filtering unit; one end of the signal preprocessing unit is connected with the input signal unit; the signal preprocessing unit can perform pulse width modulation and dead zone control on an input signal; one end of the power amplification unit is connected with the signal preprocessing unit, and the power amplification unit can amplify the PWM signal output by the signal preprocessing unit; the control unit is connected with the signal preprocessing unit and the power amplification unit, and can realize state detection and protection control of the power amplification unit; the filtering unit plays a bridging role between the power amplification unit and the load, can realize impedance matching between the power amplification unit and the load, and simultaneously filters high-frequency noise in the power signal to restore useful signals.
Preferably, the signal preprocessing unit includes: a filter control circuit, a gain control circuit, a loop filter, a PWM modulator, a timing control circuit and a path controller; the filtering control circuit and the gain control circuit can carry out noise filtering and gain control on the input analog signals; the filtering control circuit and the gain control circuit are connected with the loop filter.
Preferably, the loop filter can feed back the output stage signal of the power amplification unit to the loop filter, and compare the output stage signal with the input signal of the loop filter, so as to compensate and correct the output signal of the power amplification, improve the power amplification degree and reduce the ripple wave in the power supply. The loop filter includes: a loop filter output; the loop filter output is connected to the PWM modulator.
Preferably, the PWM modulator is capable of modulating the waveform output by the loop filter to generate a PWM signal, and sending the PWM signal to the timing control circuit; the time sequence control circuit is connected with the PWM modulator, and can introduce dead time into PWM signals output by the PWM modulator to avoid damage caused by simultaneous conduction of upper and lower bridge arms of the power amplifier unit; the access controller can control the on-off of the time sequence controller and the power amplifier unit; when the access controller is on, the power amplification unit has an input signal, and when the access controller is off, the power amplification unit has no input signal.
Preferably, the power amplifier unit includes: a gate drive circuit, an H-bridge circuit and an information sampling circuit; the gate electrode driving circuit is connected with the time sequence control circuit and is used for improving the driving capability of the output signal of the time sequence control circuit and ensuring the normal operation of the H bridge; the H-bridge circuit includes: 4 high-power MOSFETs; the H bridge circuit can amplify the output signal of the gate drive circuit to generate a high-voltage and high-current power signal, and the output of the H bridge is connected with the matched filter.
Preferably, the information acquisition circuit can respectively sample current information of a power supply end of the H bridge circuit, voltage information of an output end of the H bridge and working temperature of the H bridge; the information acquisition circuit can send the current information and the temperature information into the control unit; the information acquisition circuit is capable of sending voltage information to the loop filter.
Preferably, the control unit includes: a master control circuit, 485 communication circuit; the main control circuit is connected with the information acquisition circuit and is used for acquiring current and temperature information; the main control circuit is connected with the 485 communication circuit and is used for realizing communication with an upper computer; the main control circuit is connected with the signal preprocessing unit and is used for controlling whether a channel controller in the signal preprocessing unit works or not, so that the protection control of the power amplification unit is realized; the 485 communication circuit can be used for receiving an access command of the upper computer, and then packaging and uploading working state information of the power amplification unit to the upper computer, so that real-time monitoring of the power amplification unit is realized.
According to the matched filtering method provided by the invention, a digital power amplifier suitable for actively towing a transmitting line array is adopted, and the matched filtering method comprises the following steps:
step one: according to the working frequency band required by design index, combining the measured impedance value (susceptance B and conductance G) of the transducer and the emission response SvL, determining G by the formula M1 X Is a value of (2);
therein, svL max For maximum transmit voltage response in the band, G is the transducer equivalent conductance, G X Equivalent conductance for the matched filtering unit;
step two: specifyingValue, calculated according to formula M2->A value;
wherein,,the phase angle of the matched filtering unit is;
step three: calculation of B from M3 L2 The value is R, Z obtained from the formulas M4 and M5 X ；
Wherein B is L2 Is the inductance L 2 Susceptance value, Z X Is L 2 、C 2 And the transducer form a network equivalent complex impedance;
step four: determination of Z from M6 LC A value;
wherein Z is LC Is L 1 、C 1 Equivalent series impedance;
step five: determination of L from M7 1 、C 1 A value;
the inherent resonance point power of the array element can not be obviously improved, namely L 1 、C 1 The resonance point of the value should be represented by B L2 And around the resonance point of the B loop;
generally, L 1 、C 1 The value of (2) is repeatedly calculated and corrected at each frequency point until each pointAll meet the requirements and also meet the bandwidth requirements represented by equation M1.
Preferably, the said
Compared with the prior art, the invention has the following beneficial effects:
1. the digital power amplifier suitable for the active towing transmitting line array has the characteristics of small volume and high power; through the design of integration and modularization, the digital power amplifier can be installed in a small cylindrical aluminum cylinder for a towing line array, and the maximum output power of 400W is realized.
2. The digital power amplifier suitable for the active towing transmission line array has the characteristic of high reliability; besides taking certain measures in the aspects of integration and modularization, the low failure rate of the element is ensured, and the digital power amplifier also takes protective measures such as high-temperature protection, overcurrent protection, overvoltage protection and the like, so that the working state of the power amplifier can be monitored in real time, and once abnormal conditions occur, automatic protective measures can be timely taken, and the work is restarted after the problems are eliminated.
3. The digital power amplifier suitable for the active towing transmitting line array has the characteristic of modularization; the digital power amplifier is divided into a plurality of functional modules, each functional module is finely designed, the integration degree is greatly improved, and the reliability of the digital power amplifier is also improved.
4. The digital power amplifier suitable for the active towing transmitting line array has the characteristic of intellectualization; the digital power amplifier has the RS485 communication function by adding the control unit, can perform data interaction with external equipment, and achieves the intelligentization of the digital power amplifier.
Drawings
Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, given with reference to the accompanying drawings in which:
FIG. 1 is a schematic diagram of the component blocks of the present invention.
Fig. 2 is a schematic diagram of an internal component block of a power amplifying unit in a power amplifier according to an embodiment of the present invention.
Fig. 3 is a schematic diagram of internal components of a matched filter unit in a power amplifier according to an embodiment of the present invention.
Fig. 4 is a schematic diagram of a power amplifier operation flow in an embodiment of the invention.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the present invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications could be made by those skilled in the art without departing from the inventive concept. These are all within the scope of the present invention.
As shown in fig. 1 to 4, a digital power amplifier according to the present invention includes: the device comprises a signal preprocessing unit, a power amplification unit, a control unit, an input signal unit and a filtering unit; one end of the signal preprocessing unit is connected with the input signal unit; the signal preprocessing unit can perform pulse width modulation and dead zone control on an input signal; one end of the power amplification unit is connected with the signal preprocessing unit, and the power amplification unit can amplify the PWM signal output by the signal preprocessing unit; the control unit is connected with the signal preprocessing unit and the power amplification unit, and can realize state detection and protection control of the power amplification unit; the filtering unit plays a bridging role between the power amplification unit and the load, can realize impedance matching between the power amplification unit and the load, and simultaneously filters high-frequency noise in the power signal to restore useful signals.
Preferably, the signal preprocessing unit includes: a filter control circuit, a gain control circuit, a loop filter, a PWM modulator, a timing control circuit and a path controller; the filtering control circuit and the gain control circuit can carry out noise filtering and gain control on the input analog signals; the filtering control circuit and the gain control circuit are connected with the loop filter.
Preferably, the loop filter can feed back the output stage signal of the power amplification unit to the loop filter, and compare the output stage signal with the input signal of the loop filter, so as to compensate and correct the output signal of the power amplification, improve the power amplification degree and reduce the ripple wave in the power supply. The loop filter includes: a loop filter output; the loop filter output is connected to the PWM modulator.
Preferably, the PWM modulator is capable of modulating the waveform output by the loop filter to generate a PWM signal, and sending the PWM signal to the timing control circuit; the time sequence control circuit is connected with the PWM modulator, and can introduce dead time into PWM signals output by the PWM modulator to avoid damage caused by simultaneous conduction of upper and lower bridge arms of the power amplifier unit; the access controller can control the on-off of the time sequence controller and the power amplifier unit; when the access controller is on, the power amplification unit has an input signal, and when the access controller is off, the power amplification unit has no input signal.
Preferably, the power amplifier unit includes: a gate drive circuit, an H-bridge circuit and an information sampling circuit; the gate electrode driving circuit is connected with the time sequence control circuit and is used for improving the driving capability of the output signal of the time sequence control circuit and ensuring the normal operation of the H bridge; the H-bridge circuit includes: 4 high-power MOSFETs; the H bridge circuit can amplify the output signal of the gate drive circuit to generate a high-voltage and high-current power signal, and the output of the H bridge is connected with the matched filter.
Preferably, the information acquisition circuit can respectively sample current information of a power supply end of the H bridge circuit, voltage information of an output end of the H bridge and working temperature of the H bridge; the information acquisition circuit can send the current information and the temperature information into the control unit; the information acquisition circuit is capable of sending voltage information to the loop filter.
Preferably, the control unit includes: a master control circuit, 485 communication circuit; the main control circuit is connected with the information acquisition circuit and is used for acquiring current and temperature information; the main control circuit is connected with the 485 communication circuit and is used for realizing communication with an upper computer; the main control circuit is connected with the signal preprocessing unit and is used for controlling whether a channel controller in the signal preprocessing unit works or not, so that the protection control of the power amplification unit is realized; the 485 communication circuit can be used for receiving an access command of the upper computer, and then packaging and uploading working state information of the power amplification unit to the upper computer, so that real-time monitoring of the power amplification unit is realized.
Specifically, in one embodiment, the digital power amplifier is composed of four parts, namely a signal preprocessing unit, a power amplifying unit, a control unit and a matched filtering unit.
The signal preprocessing unit plays a role of bandpass filtering. The analog signal processing device receives an externally input analog small signal, and filters noise mixed in the input signal through a band-pass filter formed by a low-noise operational amplifier, so that an analog signal with high signal-to-noise ratio is output.
The power amplifying unit plays a role of power amplification, and the internal composition of the power amplifying unit is shown in fig. 2, and the power amplifying unit comprises a driver, an automatic gain controller, a loop filter, a PWM modulator, a channel controller, a time sequence controller, a gate electrode driver, a power switch, a protection controller, a temperature sensor, a current sensor and a startup short circuit detection circuit. The power amplifying unit firstly receives the analog signal output by the signal preprocessing unit, and sends the analog signal to the loop filter after passing through the driver and the automatic gain controller. And meanwhile, the power amplifier output stage signal is fed back to the loop filter and is compared with the input signal of the loop filter, so that the power amplifier output signal is compensated, corrected and noise shaped, the degree of power amplifier linearity is improved, and the ripple wave in the power supply is reduced (namely the power supply rejection ratio is improved). The output of the loop filter serves as the input signal to a PWM modulator, which encodes the input signal into a binary pulse train. The access controller is used for controlling the on-off of the access, when the power amplifier fails, the connection between the PWM modulator and the time sequence controller is disconnected through the access controller, so that the power amplifier is in a silent state, and when the power amplifier is normal, the access controller conducts the connection between the PWM modulator and the time sequence controller, and PWM signals smoothly enter a post-stage circuit for amplification. In order to prevent the phenomenon that the on-time and the off-time of the power switch coexist to cause instantaneous high-current punch-through on the power switch, dead time is introduced into a driving signal of the power switch, and the function is realized by a time sequence controller, wherein the function is to keep the turn-off of one power tube before the turn-off of the other power tube is not completed, namely, in the working time sequence of the whole power tube, two power tubes are turned off at the same time for a short time in a period of time. The introduction of dead time improves efficiency and avoids burning out the device. In general, the output signal of the timing controller cannot directly drive the power switch, and for this purpose, a gate driver is added at the back end of the timing controller to enhance the driving capability of the signal. The output signal of the gate driver is used for driving the power switch to work, so that the power amplification of the signal is realized. The power switch adopts a full-bridge structure, and the full-bridge topology has the following advantages: the adaptive power range is large, from tens of watts to kilowatts; the power supply fluctuation can be effectively restrained. In addition, the power amplifying unit is further provided with a temperature sensor, a current sensor and a startup short circuit detection circuit, the information is uploaded to the control unit through the protection controller, and the control unit controls whether the power amplifying unit works or not according to the working state of the power amplifying unit. The power amplifying unit designed by the method has the output power as high as 400W under the condition of single power supply 50V.
The matched filtering unit has the functions of: 1. impedance matching between the power amplifying unit and the transmitting transducer is realized, so that the output efficiency of the power amplifier is improved, and reactive power is reduced; 2. filtering out high frequency components in the power signal and recovering the fundamental frequency signal. The matched filtering unit adopts a third-order Butterworth filter structure, and the internal structure is shown in figure 3. The matching filter unit controls the impedance phase angle difference of the whole matching filter network within +/-10 degrees, the proportion of active power is increased, the requirement on the power capacity of the power amplifier is effectively reduced, and meanwhile, the size is reduced.
The control unit collects over-temperature indication information, over-current indication information and normal operation indication information output by the power amplification unit, judges the working state of the power amplification unit after data processing, and outputs reset information to the power amplification unit once the working state is abnormal, when the power amplification unit receives a reset command, the internal protection controller controls the access controller to be disconnected, so that the signal access is disconnected, the power amplification unit is in a silent state, and the access controller is switched on again after the working state of the power amplification unit is normal, so that the power amplification unit enters the working mode again. In addition, the control unit also expands the RS485 communication function, and external equipment can access the control unit through the RS485 bus, so that the working state information of the power amplification unit is obtained, and the real-time monitoring of the working state of the power amplification unit is realized.
Specifically, in one embodiment, as shown in fig. 4, a digital power amplifier includes a signal preprocessing unit, a power amplifying unit, a matched filtering unit, a control unit, a signal source, a power supply, a transmitting transducer and a host. Wherein the signal source is used as a signal generator to output an analog sine signal. The output of the signal source is used as the input of the signal preprocessing unit, and the signal preprocessing unit filters the input signal and sends the filtered input signal to the power amplifying unit.
The digital power amplifier firstly receives the analog signal output by the signal preprocessing unit, and sends the analog signal to the loop filter after passing through the driver and the automatic gain controller. And meanwhile, the power amplifier output stage signal is fed back to the loop filter and is compared with the input signal of the loop filter, so that the power amplifier output signal is compensated, corrected and noise shaped, the degree of power amplifier linearity is improved, and the ripple wave in the power supply is reduced (namely the power supply rejection ratio is improved). The output of the loop filter serves as the input signal to a PWM modulator, which encodes the input signal into a binary pulse train. The access controller is used for controlling the on-off of the access, when the power amplifier fails, the connection between the PWM modulator and the time sequence controller is disconnected through the access controller, so that the power amplifier is in a silent state, and when the power amplifier is normal, the access controller conducts the connection between the PWM modulator and the time sequence controller, and PWM signals smoothly enter a post-stage circuit for amplification. In order to prevent the phenomenon that the on-time and the off-time of the power switch coexist to cause instantaneous high-current punch-through on the power switch, dead time is introduced into a driving signal of the power switch, and the function is realized by a time sequence controller, wherein the function is to keep the turn-off of one power tube before the turn-off of the other power tube is not completed, namely, in the working time sequence of the whole power tube, two power tubes are turned off at the same time for a short time in a period of time. The introduction of dead time improves efficiency and avoids burning out the device. The output signal of the time sequence controller can not directly drive the power switch, and therefore, a gate electrode driver is added at the rear end of the time sequence controller to enhance the driving capability of the signal. The output signal of the gate driver is used for driving the power switch to work, so that the power amplification of the signal is realized. Besides, a temperature sensor, a current sensor and a startup short circuit detection circuit are additionally arranged in the power amplification unit, and the information is uploaded to the control unit through the protection controller.
The power source required by the power amplifying unit is provided by a power source, and the power source outputs 50V direct current and the power is more than 500W. The power signal output by the power amplifying unit is output to the matched filtering unit, the matched filtering unit filters the input signal to restore the useful signal, and meanwhile, the impedance matching of the power amplifying unit and the transmitting transducer is realized. The matched filtering unit outputs a power sine signal for driving the transmitting transducer to work.
The control unit receives the over-temperature indication information, the over-current indication information and the normal operation indication information input by the power amplification unit, so as to judge whether the power amplification unit works normally. When judging that the power amplifying unit fails, the control unit outputs reset information and controls the power amplifying unit to stop working; when the power amplification unit is judged to be normal, the control unit cancels the reset instruction, so that the power amplification unit restarts to work. The control unit contains an RS485 external interface through which communication with the host is maintained. The host accesses the control unit through the corresponding instruction and receives the current and voltage information under the working state of the power amplifying unit, so that the working state of the power amplifying unit is intuitively known.
Specifically, in another embodiment, the power amplifier of the present invention is employed in a towed transmit line array. The power amplifier was packed in a cylindrical aluminum cylinder of Φ50×120mm and immersed in light naphthalene oil. The power supply adopts a switching power supply module, outputs 50V of voltage and 500W of power, and provides high-power direct current for the power amplifier. The transmitting transducer adopts the embedded tangential polarization piezoelectric ceramic ring, and has the advantages of large power capacity, high structural strength, stable and reliable performance and the like. In the test process, the transmitting transducer is placed in water, and the water depth is 6 meters. The host consists of a computer with an RS485 port, and the host transmits access information to the control unit, so that the working state information of the power amplifier is obtained and displayed on a host interface, and the real-time monitoring of the power amplifier is realized.
The actual measurement shows that the output power of the power amplifier in the working frequency band is more than 400W. The operating temperature conditions of the power amplifier are shown in the following table:
after a long period of operation, the wall temperature of the power amplifier tends to be stable and float around 45 ℃. In the whole working process, the power amplifier runs stably and reliably all the time, and the reliability of the power amplifier is verified.
In summary, the present invention provides a high performance digital power amplifier suitable for towing an array of transmit lines: the traditional D-type power amplifier is improved, a negative feedback circuit is added, and the distortion rate and electromagnetic interference of signals are reduced; the impedance matching between the power amplifying unit and the transmitting transducer and the restoring filtering of the signals are realized through the matched filtering unit, so that the class D power amplifier is suitable for capacitive loads such as the transmitting transducer; the state self-checking and the data interaction of the class D power amplifier are realized through the addition of control, so that the intellectualization of the class D power amplifier is achieved. Through the design, the digital power amplifier meets the requirement of towing the transmitting line array, and is successfully applied to the high-power towing transmitting line array.
According to the matched filtering method provided by the invention, a digital power amplifier suitable for actively towing a transmitting line array is adopted, and the matched filtering method comprises the following steps:
step one: according to the working frequency band required by design index, combining the measured impedance value (susceptance B and conductance G) of the transducer and the emission response SvL, determining G by the formula M1 X Is a value of (2);
therein, svL max For maximum transmit voltage response in the band, G is the transducer equivalent conductance, G X Equivalent conductance for the matched filtering unit;
step two: specifyingValue, calculated according to formula M2->A value;
wherein,,the phase angle of the matched filtering unit is;
step three: calculation of B from M3 L2 The value is R, Z obtained from the formulas M4 and M5 X ；
Wherein B is L2 Is the inductance L 2 Susceptance value, Z X Is L 2 、C 2 And the transducer form a network equivalent complex impedance;
step four: determination of Z from M6 LC A value;
wherein Z is LC Is L 1 、C 1 Equivalent series impedance;
step five: determination of L from M7 1 、C 1 A value;
the inherent resonance point power of the array element can not be obviously improved, namely L 1 、C 1 The resonance point of the value should be represented by B L2 And around the resonance point of the B loop;
generally, L 1 、C 1 The value of (2) is repeatedly calculated and corrected at each frequency point until each pointAll meet the requirements and also meet the bandwidth requirements represented by equation M1.
Preferably, the said
The digital power amplifier suitable for the active towing transmitting line array has the characteristics of small volume and high power; through the design of integration and modularization, the digital power amplifier can be installed in a small cylindrical aluminum cylinder for a towing line array, and the maximum output power of 400W is realized. The digital power amplifier suitable for the active towing transmission line array has the characteristic of high reliability; besides taking certain measures in the aspects of integration and modularization, the low failure rate of the element is ensured, and the digital power amplifier also takes protective measures such as high-temperature protection, overcurrent protection, overvoltage protection and the like, so that the working state of the power amplifier can be monitored in real time, and once abnormal conditions occur, automatic protective measures can be timely taken, and the work is restarted after the problems are eliminated. The digital power amplifier suitable for the active towing transmitting line array has the characteristic of modularization; the digital power amplifier is divided into a plurality of functional modules, each functional module is finely designed, the integration degree is greatly improved, and the reliability of the digital power amplifier is also improved. The digital power amplifier suitable for the active towing transmitting line array has the characteristic of intellectualization; the digital power amplifier has the RS485 communication function by adding the control unit, can perform data interaction with external equipment, and achieves the intelligentization of the digital power amplifier.
Those skilled in the art will appreciate that the invention provides a system and its individual devices, units in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, embedded microcontrollers, etc. all but by implementing the invention in the form of a pure computer readable program code. Therefore, the system and various devices, units and units thereof provided by the invention can be regarded as a hardware component, and the devices, units and units for realizing various functions included in the system can also be regarded as structures in the hardware component; means, units for implementing various functions may also be regarded as either software units implementing the method or structures within hardware components.
The foregoing describes specific embodiments of the present invention. It is to be understood that the invention is not limited to the particular embodiments described above, and that various changes or modifications may be made by those skilled in the art within the scope of the appended claims without affecting the spirit of the invention. The embodiments of the present application and features in the embodiments may be combined with each other arbitrarily without conflict.
Claims (8)
1. A digital power amplifier, comprising: the device comprises a signal preprocessing unit, a power amplification unit, a control unit, an input signal unit and a filtering unit;
one end of the signal preprocessing unit is connected with the input signal unit; the signal preprocessing unit can perform pulse width modulation and dead zone control on an input signal;
one end of the power amplification unit is connected with the signal preprocessing unit, and the power amplification unit can amplify the PWM signal output by the signal preprocessing unit;
the control unit is connected with the signal preprocessing unit and the power amplification unit, and can realize state detection and protection control of the power amplification unit;
the filtering unit can realize impedance matching between the power amplification unit and the load and simultaneously filter high-frequency noise in the power signal;
also included is a matched filtering method for a digital power amplifier adapted for actively towing an array of transmit lines, comprising:
step one: according to the working frequency band required by the design index, combining the measured impedance value and the emission response SvL of the transducer, determining G by the formula M1 X Is a value of (2);
therein, svL max For maximum transmit voltage response in the band, G is the transducer equivalent conductance, G X Equivalent conductance for the matched filtering unit;
step two: specifyingValue, calculated according to formula M2->A value;
wherein,,the phase angle of the matched filtering unit is;
step three: calculation of B from M3 L2 The value is R, Z obtained from the formulas M4 and M5 X ；
Wherein B is L2 Is the inductance L 2 Susceptance value, Z X Is L 2 、C 2 And the transducer form a network equivalent complex impedance;
step four: determination of Z from M6 LC A value;
wherein Z is LC Is L 1 、C 1 Equivalent series impedance;
step five: determination of L from M7 1 、C 1 A value;
L 1 、C 1 the resonance point of the value should be represented by B L2 And around the resonance point of the B loop;
L 1 、C 1 the value of (2) is repeatedly calculated and corrected at each frequency point until each pointAll meet the requirements and also meet the bandwidth requirements represented by equation M1.
2. The digital power amplifier according to claim 1, wherein the signal preprocessing unit includes: a filter control circuit, a gain control circuit, a loop filter, a PWM modulator, a timing control circuit and a path controller;
the filtering control circuit and the gain control circuit can carry out noise filtering and gain control on the input analog signals;
the filtering control circuit and the gain control circuit are connected with the loop filter.
3. The digital power amplifier of claim 2, wherein the loop filter is capable of feeding back a power amplifier unit output stage signal to the loop filter for comparison with an input signal of the loop filter;
the loop filter includes: a loop filter output;
the loop filter output is connected to the PWM modulator.
4. The digital power amplifier according to claim 3, wherein the PWM modulator is capable of modulating the waveform output from the loop filter to generate a PWM signal, and feeding the PWM signal into the timing control circuit;
the time sequence control circuit is connected with the PWM modulator and can introduce dead time into PWM signals output by the PWM modulator;
the access controller can control the on-off of the time sequence controller and the power amplifier unit.
5. The digital power amplifier according to claim 2, wherein the power amplifying unit includes: the gate electrode driving circuit, the H-bridge circuit and the information acquisition circuit;
the gate electrode driving circuit is connected with the time sequence control circuit;
the H-bridge circuit includes: 4 MOSFETs;
the power of the MOSFET is larger than a set threshold value;
the H-bridge circuit can amplify an output signal of the gate driving circuit.
6. The digital power amplifier according to claim 5, wherein the information acquisition circuit is capable of sampling current information of a power supply terminal of the H-bridge circuit, voltage information of an output terminal of the H-bridge, and an operating temperature of the H-bridge, respectively;
the information acquisition circuit can send the current information and the temperature information into the control unit;
the information acquisition circuit is capable of sending voltage information to the loop filter.
7. The digital power amplifier according to claim 5, wherein the control unit comprises: a master control circuit, 485 communication circuit;
the main control circuit is connected with the information acquisition circuit;
the main control circuit is connected with the 485 communication circuit;
the main control circuit is connected with the signal preprocessing unit;
the 485 communication circuit can be used for receiving an access command of the upper computer.
8. The digital power amplifier of claim 1, wherein the
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| CN1968007A (en) * | 2005-11-16 | 2007-05-23 | 弥亚微电子（上海）有限公司 | Digital power amplifier adapted for low-voltage carrier communication |
| CN101203062A (en) * | 2007-07-20 | 2008-06-18 | 徐利梅 | Method for numeral sound signal processing and digital type sound frequency directional loudspeaker |
| CN205176527U (en) * | 2015-12-01 | 2016-04-20 | 山东科技大学 | Many rounds of independent driven robot controllers |
| CN106160677A (en) * | 2016-06-16 | 2016-11-23 | 长沙湘计海盾科技有限公司 | A kind of carried shift PWM modulation type digital power amplifier and power-magnifying method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB9506725D0 (en) * | 1995-03-31 | 1995-05-24 | Hooley Anthony | Improvements in or relating to loudspeakers |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1968007A (en) * | 2005-11-16 | 2007-05-23 | 弥亚微电子（上海）有限公司 | Digital power amplifier adapted for low-voltage carrier communication |
| CN101203062A (en) * | 2007-07-20 | 2008-06-18 | 徐利梅 | Method for numeral sound signal processing and digital type sound frequency directional loudspeaker |
| CN205176527U (en) * | 2015-12-01 | 2016-04-20 | 山东科技大学 | Many rounds of independent driven robot controllers |
| CN106160677A (en) * | 2016-06-16 | 2016-11-23 | 长沙湘计海盾科技有限公司 | A kind of carried shift PWM modulation type digital power amplifier and power-magnifying method |
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