1
Introduction
ultrasonic
mounted
by ultrasonic power inverter transducer. In recent years, because the research
and development of the victory of the new rare earth efficacy data, the
production of high-power ultrasonic transducer as possible, but the accompanying
high-frequency sine wave inverter power supply products are still rare. At
present, the market of high-power sine power inverter are IGBT made in
low-frequency, high frequency inverter power most power or duty cycle of the
square wave pulse inverter power adjustable. Therefore, high-frequency
high-power sinusoidal power inverter has become a bottleneck ultrasonic
utilization, makes the development of the power supply has become a pressing
problem. Here, the use of the mixed pulse width modulation (Hybrid Pulse Width
Modulation, HPWM) control skills MOSFET parallel operation mode, the use of
single-chip composed of intelligent control system, high-performance, high-power
sine the ultrasonic wave inverter power development in the discussion.
2 system formation
for high-performance, high-power the sine ultrasonic power inverter, and its frequency is 25kHz, the power of 4.5kW. Voltage request is adjustable between 0 ~ 200V, adjustable frequency between 10 ~ 25kHz.
2f672f2b6f77980b075f2b0b40978b65 design
Figure 1 shows the power inverter a block diagram showing the configuration of the system hardware. It consists of two major departments of the AC / DC and DC / AC. AC - DC - AC main circuit, driving circuit, MCU control system, a low-pass filter, display and cover other important links.
main circuit directly powered by 220V mains. The single-phase switching voltage by a thyristor the constant current constant voltage control module will be exchanged is converted to DC of the inverter for supplying a constant DC voltage.
To make the inverter can be a function with the incomparable good sinusoidal output waveform, there need to be greater than the carrier. Because its carrier signal will reach 400 ~ 600kHz, and thus can only use the MOSFET as a switching device. However, the output power of the MOSFET is small and can be taken in order to increase the output power, the way to solve the resistance to high-frequency and high-power MOSFET parallel operation.
inverter partial asynchronous modulation constant frequency triangular carrier signal input sine wave. Grasp the way take HPWM skills. The inverse of the DC voltage pulse signal into a series of amplitude. Amplitude with the pulse width of the pulse signal is always proportional to the modulating sine wave. These pulse signals are filtered via low pass filter, a high-frequency carrier signal. Can be obtained with the modulation wave with the frequency of the sine wave output. Therefore only the transformation of the input modulated wave, can be easily achieved adjustable amplitude, variable frequency sine wave output.
22 microcontroller dominated system
The power supply uses specially designed for the control of the inverter 80C196MC microcontroller as the control center of the inverter. 80C196MC microcontroller internal waveform generator WFG, the CPU time is very short. By P6 port directly output 4 PWM signals for the inverter drive. Formed by 80C196MC and EPROM2764 minimum microcomputer system. Will be given of the ultrasonic frequency and voltage magnitude. As well as the setting of the carrier frequency, and mimic the output unipolar sine wave with constant amplitude pulse width modulation HPWM signal. The display of the voltage amplitude and frequency can be realized. And maintenance of the power supply control.
23 inverter main circuit and HPWM of restraint methods
when running in high frequency the great switching losses of the power tube. The device is easy to damage, limit the power increases. The crucial technical difficulties of the power is in the the high frequency premise How to get high-power variable frequency sine wave output. Inverter difficulty is how to decline the the switch switching losses, du / dt and di / dt stress greatly reduced, in order to achieve the high-frequency inverter. In order to reach these goals. The main circuit of the inverter uses a single-phase full-bridge topology structure easy to implement soft-switching technology. In a controlled manner using the the HPWM control mode. Figure 2 illustrates the topology of the main circuit of the inverter. Figure 3 illustrates the output signal of the four switch control of the drive signal and the inverter.
HPWM to grasp the nature of the way is still a unipolar SPWM control. The output of the inverter bridge is a tri-state output voltage wave shape. The sinusoidal modulating wave and the triangular carrier wave in the positive half cycle of the output voltage of the AC / sectional generating a pulse signal control VS2 and VS4 arm restraint VS1 and VS3 bridge Arm HF complementary off; low frequency complementary off, i.e. VS2 off, VS4 guide through. In the negative half cycle of the output voltage, the exchange of the working status of the two bridge arm. The VS1 always off, VS3 always brought into conduction, VS2, and VS4 high-frequency modulation operation. HPWM control mode, the total two power tube work in the low-frequency case, reducing the switching losses in general,power inverter, this progress in the high-frequency power is extremely favorable. Unmatched individual SPWM dominated. Two leg work alternately in the low-frequency and high-frequency conditions HPWM way, the two leg work symmetrically balanced power tube working conditions, which will extend the life of the power tube, to all circuit robustness additions, there are voltage applications rate, the harmonic content, low switching losses strengths. Because each switch in parallel with a capacitor filter inductance parameter choices appropriate circumstances, the circuit is very easy to achieve zero-voltage switch-off (ZVS), du / dt and di / dt stress greatly landing,Grid tie inverter, complete to to achieve the high-frequency power inverter.
24 driver circuit switch driver circuit latest LM5111 drives can be used. SOIC-8 pin package, and to support the use of input and output stage supply alone break ground and reference voltage pin, leaving the power supply design gate drive configuration. The LM5111 chip peak output currents up to 5A LM5111's two of 5A current drive channel can be individually broken, can also be parallel convergence, the peak output drive current progress to 10A, in order to be able to drive great power MOSFET high effectiveness. LM5111's operating frequency up to 1MHz, enlightened, off delay resolution of 12ns and 14ns. Able to complete satisfaction of the power of the request.
3 software
31 main program
Figure 4 shows the main program flow chart. It includes a subroutine initialization subroutine, HPWM signal, keyboard scanning and display routines. Initialization routine the Application of 80C196MC on stack address and carrier frequency parameters initialization and microcontroller I / O ports, suspension and waveform generator set operating mode. Keyboard given desired output sine wave frequency is displayed by the display program. Subroutine of the voltage signal timing sampling A / D conversion, dynamic, time-sharing the frequency and amplitude of the sine wave value.
32 HPWM signal the subroutine
HPWM is comparable to that generated by the sinusoidal modulation wave with the amplitude of the triangular carrier. Waveform generator core alignment mode, the counting process of the WG-COUNTER constitute an imaginary triangle wave carrier. Sinusoidal modulation wave can be achieved through the look-up table. Because output HPWM wave has symmetry, so long as to establish 0 ° ~ 180 ° of the sine function table. Every 0.15 ° sine function table in order to reach the adequate identification rate, the deployment of a sampling point, each data with 15-bit binary value, accounting for two-byte, half cycle of the output sine 1200 of data sent the presence of starting address for the storage area of the SIGN. Carrier frequency fc, the output frequency is fo, each half cycle of sine wave output is required of N =-fc / FO intersection value, corresponding to the intersection of the i-th sinusoidal modulation amplitude value can be obtained through the look-up table, the address SIGN +1200 i / N.
the triangular carrier at the intersection of sinusoidal modulation amplitudes analogy to to obtain inverter HPWM switch mode. Whenever the peak of the triangular wave carrier (WG-COUNTER = WG-RELOAD) or bottom to the microcontroller the aborted plea, data loading. So, each half cycle of the AC two-phase to obtain hybrid unipolar modulation mode HPWM wave. Figure 5 illustrates HPWM signal generating subroutine flowchart.
4 test results
the main circuit structure, control method, developed an output frequency of 25kHz; carrier frequency of 600kHz; principle prototype output power of 4.5kW. Figure 6a, b shows the filter inductor the rational half load and rational full load current iL and output voltage uo experimental waveforms. The figure shows that half load and full load, uo change smaller have better load swap rate. Figure 6c, d shows the drive voltage inverter bridge unified one leg two power tube VS2 and VS4 ugsVS2 and ugsVS4 the enlarged ugsVS2 and ugsVS4 test waveforms. Visible, as appropriate, to the death zone, unified leg two power tubes are complementary conduction. Power tube drive voltage waveform rebound and landed delay time is extremely short, may contentment requirements. The judge
5 the psionic control system, single-chip high-power ultrasonic power, artificial power frequency and output voltage setting. Simplifies hardware circuit the HPWM signal microcontroller mimic the output, greatly improving the power factor and the effectiveness of the system,www.12vgridtiepowerinverters.com; applied HPWM control mode with ZVS resonant soft-switching technology, the decline in the loss of the switch, restraint and high-order harmonic reduced transducer losses. The experiments show the excellent performance of power, adjust convenient, reliable high. For high-power ultrasonic transducer provides excellent performance in various aspects of the use of ultrasonic power.
2 system formation
for high-performance, high-power the sine ultrasonic power inverter, and its frequency is 25kHz, the power of 4.5kW. Voltage request is adjustable between 0 ~ 200V, adjustable frequency between 10 ~ 25kHz.
2f672f2b6f77980b075f2b0b40978b65 design
Figure 1 shows the power inverter a block diagram showing the configuration of the system hardware. It consists of two major departments of the AC / DC and DC / AC. AC - DC - AC main circuit, driving circuit, MCU control system, a low-pass filter, display and cover other important links.
main circuit directly powered by 220V mains. The single-phase switching voltage by a thyristor the constant current constant voltage control module will be exchanged is converted to DC of the inverter for supplying a constant DC voltage.
To make the inverter can be a function with the incomparable good sinusoidal output waveform, there need to be greater than the carrier. Because its carrier signal will reach 400 ~ 600kHz, and thus can only use the MOSFET as a switching device. However, the output power of the MOSFET is small and can be taken in order to increase the output power, the way to solve the resistance to high-frequency and high-power MOSFET parallel operation.
inverter partial asynchronous modulation constant frequency triangular carrier signal input sine wave. Grasp the way take HPWM skills. The inverse of the DC voltage pulse signal into a series of amplitude. Amplitude with the pulse width of the pulse signal is always proportional to the modulating sine wave. These pulse signals are filtered via low pass filter, a high-frequency carrier signal. Can be obtained with the modulation wave with the frequency of the sine wave output. Therefore only the transformation of the input modulated wave, can be easily achieved adjustable amplitude, variable frequency sine wave output.
22 microcontroller dominated system
The power supply uses specially designed for the control of the inverter 80C196MC microcontroller as the control center of the inverter. 80C196MC microcontroller internal waveform generator WFG, the CPU time is very short. By P6 port directly output 4 PWM signals for the inverter drive. Formed by 80C196MC and EPROM2764 minimum microcomputer system. Will be given of the ultrasonic frequency and voltage magnitude. As well as the setting of the carrier frequency, and mimic the output unipolar sine wave with constant amplitude pulse width modulation HPWM signal. The display of the voltage amplitude and frequency can be realized. And maintenance of the power supply control.
23 inverter main circuit and HPWM of restraint methods
when running in high frequency the great switching losses of the power tube. The device is easy to damage, limit the power increases. The crucial technical difficulties of the power is in the the high frequency premise How to get high-power variable frequency sine wave output. Inverter difficulty is how to decline the the switch switching losses, du / dt and di / dt stress greatly reduced, in order to achieve the high-frequency inverter. In order to reach these goals. The main circuit of the inverter uses a single-phase full-bridge topology structure easy to implement soft-switching technology. In a controlled manner using the the HPWM control mode. Figure 2 illustrates the topology of the main circuit of the inverter. Figure 3 illustrates the output signal of the four switch control of the drive signal and the inverter.
HPWM to grasp the nature of the way is still a unipolar SPWM control. The output of the inverter bridge is a tri-state output voltage wave shape. The sinusoidal modulating wave and the triangular carrier wave in the positive half cycle of the output voltage of the AC / sectional generating a pulse signal control VS2 and VS4 arm restraint VS1 and VS3 bridge Arm HF complementary off; low frequency complementary off, i.e. VS2 off, VS4 guide through. In the negative half cycle of the output voltage, the exchange of the working status of the two bridge arm. The VS1 always off, VS3 always brought into conduction, VS2, and VS4 high-frequency modulation operation. HPWM control mode, the total two power tube work in the low-frequency case, reducing the switching losses in general,power inverter, this progress in the high-frequency power is extremely favorable. Unmatched individual SPWM dominated. Two leg work alternately in the low-frequency and high-frequency conditions HPWM way, the two leg work symmetrically balanced power tube working conditions, which will extend the life of the power tube, to all circuit robustness additions, there are voltage applications rate, the harmonic content, low switching losses strengths. Because each switch in parallel with a capacitor filter inductance parameter choices appropriate circumstances, the circuit is very easy to achieve zero-voltage switch-off (ZVS), du / dt and di / dt stress greatly landing,Grid tie inverter, complete to to achieve the high-frequency power inverter.
24 driver circuit switch driver circuit latest LM5111 drives can be used. SOIC-8 pin package, and to support the use of input and output stage supply alone break ground and reference voltage pin, leaving the power supply design gate drive configuration. The LM5111 chip peak output currents up to 5A LM5111's two of 5A current drive channel can be individually broken, can also be parallel convergence, the peak output drive current progress to 10A, in order to be able to drive great power MOSFET high effectiveness. LM5111's operating frequency up to 1MHz, enlightened, off delay resolution of 12ns and 14ns. Able to complete satisfaction of the power of the request.
3 software
31 main program
Figure 4 shows the main program flow chart. It includes a subroutine initialization subroutine, HPWM signal, keyboard scanning and display routines. Initialization routine the Application of 80C196MC on stack address and carrier frequency parameters initialization and microcontroller I / O ports, suspension and waveform generator set operating mode. Keyboard given desired output sine wave frequency is displayed by the display program. Subroutine of the voltage signal timing sampling A / D conversion, dynamic, time-sharing the frequency and amplitude of the sine wave value.
32 HPWM signal the subroutine
HPWM is comparable to that generated by the sinusoidal modulation wave with the amplitude of the triangular carrier. Waveform generator core alignment mode, the counting process of the WG-COUNTER constitute an imaginary triangle wave carrier. Sinusoidal modulation wave can be achieved through the look-up table. Because output HPWM wave has symmetry, so long as to establish 0 ° ~ 180 ° of the sine function table. Every 0.15 ° sine function table in order to reach the adequate identification rate, the deployment of a sampling point, each data with 15-bit binary value, accounting for two-byte, half cycle of the output sine 1200 of data sent the presence of starting address for the storage area of the SIGN. Carrier frequency fc, the output frequency is fo, each half cycle of sine wave output is required of N =-fc / FO intersection value, corresponding to the intersection of the i-th sinusoidal modulation amplitude value can be obtained through the look-up table, the address SIGN +1200 i / N.
the triangular carrier at the intersection of sinusoidal modulation amplitudes analogy to to obtain inverter HPWM switch mode. Whenever the peak of the triangular wave carrier (WG-COUNTER = WG-RELOAD) or bottom to the microcontroller the aborted plea, data loading. So, each half cycle of the AC two-phase to obtain hybrid unipolar modulation mode HPWM wave. Figure 5 illustrates HPWM signal generating subroutine flowchart.
4 test results
the main circuit structure, control method, developed an output frequency of 25kHz; carrier frequency of 600kHz; principle prototype output power of 4.5kW. Figure 6a, b shows the filter inductor the rational half load and rational full load current iL and output voltage uo experimental waveforms. The figure shows that half load and full load, uo change smaller have better load swap rate. Figure 6c, d shows the drive voltage inverter bridge unified one leg two power tube VS2 and VS4 ugsVS2 and ugsVS4 the enlarged ugsVS2 and ugsVS4 test waveforms. Visible, as appropriate, to the death zone, unified leg two power tubes are complementary conduction. Power tube drive voltage waveform rebound and landed delay time is extremely short, may contentment requirements. The judge
5 the psionic control system, single-chip high-power ultrasonic power, artificial power frequency and output voltage setting. Simplifies hardware circuit the HPWM signal microcontroller mimic the output, greatly improving the power factor and the effectiveness of the system,www.12vgridtiepowerinverters.com; applied HPWM control mode with ZVS resonant soft-switching technology, the decline in the loss of the switch, restraint and high-order harmonic reduced transducer losses. The experiments show the excellent performance of power, adjust convenient, reliable high. For high-power ultrasonic transducer provides excellent performance in various aspects of the use of ultrasonic power.
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