A high reliability converter and control method

Abstract

The present invention discloses a high-reliability converter and a control method. The converter includes a high-voltage DC source V H , low voltage DC source V L , switch tube S1 to switch tube S8, diode APD1 to diode APD8, diode SD1 to diode SD8 and filter inductor L o and capacitor C o The converter can generate six different working modes by controlling the on and off of the switch tubes S1 to S8, and convert the DC voltage into an AC voltage output. The present invention can achieve stable operation when the DC power supply fails and the switch tube fails, and there is no problem of reverse recovery of the body diode. At the same time, multi-level output can be achieved to ensure the waveform quality on the AC side.

Description

Technical Field

[0001] The invention relates to the technical field of power electronics, and in particular to a high-reliability converter and a control method. Background Art

[0002] Converters are widely used in wind power generation, photovoltaic power generation, energy storage systems, and new energy hydrogen production systems. Traditional multilevel converters include cascaded H-bridge converters, flying capacitor converters, and diode midpoint clamped converters. However, the application of traditional converters is limited by the reverse recovery current problem or capacitor voltage balancing problem during the commutation process. Ahmed et al. proposed a split-source converter with advantages such as fewer passive devices and continuous input current, but there are problems such as high stress of some switch currents, high output THD, large inductance value, and high-frequency commutation of input diodes. Wu Hongfei et al. proposed a new five-level split-source converter structure, namely a dual DC port asymmetric multilevel converter, in which two switch tubes can work without introducing dead time, with higher output voltage and current gain, but the inductor current will cause reverse recovery problems when flowing through the switch tube body diode. In addition, during the operation of the converter, the power switch device is prone to damage, resulting in the converter being unable to operate normally and stably. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a high-reliability converter and control method, so as to achieve stable operation even in the event of a power switch tube or a DC source failure, improve the converter fault tolerance, and improve the reverse recovery problem of the converter body diode.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a high-reliability converter, comprising a high-voltage DC source V H , low voltage DC source V L , switch tube S1 to switch tube S8, diode APD1 to diode APD8, diode SD1 to diode SD8 and filter inductor L o and capacitor C o ; The high voltage DC source V H The positive electrode is connected to the anode of diode SD1, the cathode of diode APD1, the anode of diode SD3, and the cathode of diode APD3 respectively; the high voltage DC source V H The negative electrode is connected to the low voltage DC source V L The negative electrode of the switch tube S2, the source electrode of the switch tube S4, the anode electrode of the diode APD4 are connected; the low voltage DC source V LThe positive electrode of the diode APD7 is respectively connected to the source of the switch tube S7, the anode of the diode APD7, the source of the switch tube S8, and the anode of the diode APD8; the cathode of the diode APD7 is respectively connected to the anode of the diode SD7, the anode of the diode SD5, and the cathode of the diode APD5; the cathode of the diode APD8 is respectively connected to the anode of the diode SD8, the anode of the diode SD6, and the cathode of the diode APD6; the anode of the diode APD5 is respectively connected to the source of the switch tube S5, the source of the switch tube S1, the anode of the diode APD1, the anode of the diode SD2, the cathode of the diode APD2, and the filter inductor L o The anode of the diode APD6 is connected to the source of the switch tube S6, the source of the switch tube S3, the anode of the diode APD3, the anode of the diode SD4, the cathode of the diode APD4, and the capacitor C o and one end of the load; the filter inductor L o The output terminals are connected to capacitors C o the other end of the switch tube S1 is connected to the cathode of the diode SD1; the drain of the switch tube S2 is connected to the cathode of the diode SD2; the drain of the switch tube S3 is connected to the cathode of the diode SD3; the drain of the switch tube S4 is connected to the cathode of the diode SD4; the drain of the switch tube S5 is connected to the cathode of the diode SD5; the drain of the switch tube S6 is connected to the cathode of the diode SD6; the drain of the switch tube S7 is connected to the cathode of the diode SD7; the drain of the switch tube S8 is connected to the cathode of the diode SD8.

[0005] A further improvement of the technical solution of the present invention is that: the driving signal of the switch tube S1 is composed of a modulation wave V ref and the first carrier V cr1 After voltage comparison, V ref Greater than V cr1 When the output is high level, otherwise it outputs low level; the drive signal of the switch tube S5 is modulated by the wave V ref and the third carrier V cr3 After voltage comparison, V ref Greater than V cr3 When the output is high level, otherwise it outputs low level; the drive signal of the switch tube S4 is modulated by the modulation wave V ref and the fourth carrier V cr4 After voltage comparison, V ref Greater than V cr4 When the output is high level, otherwise it outputs low level; the drive signal of the switch tube S8 is modulated by the wave V ref and the second carrier V cr2 After voltage comparison, V ref Greater than V cr2The output is high level when the switch is on, otherwise it outputs low level; the drive signals of the switch tube S1 and the switch tube S7 are complementary; the drive signals of the switch tube S2 and the switch tube S5 are complementary; the drive signals of the switch tube S4 and the switch tube S6 are complementary; the drive signals of the switch tube S3 and the switch tube S8 are complementary; the third carrier V cr3 With the fourth carrier V cr4 The two are generated in a phase shifting manner, with a phase difference of 180 degrees and the same waveform. The first carrier V cr1 With the second carrier V cr2 The waveforms are consistent, and are generated in a carrier stacking manner on the third carrier V cr3 The upper and fourth carrier V cr4 Below.

[0006] The further improvement of the technical solution of the present invention is: a high-reliability converter control method, which generates six working modes by controlling the on and off of the switch tubes S1 to S8, converts the DC voltage into an AC voltage output, and outputs five different levels. The specific control method is as follows:

[0007] The first working mode: when the driving signal of the switch tube S4, the switch tube S5, the switch tube S7 and the switch tube S8 is at a high level, the switch tube S4, the switch tube S5, the switch tube S7 and the switch tube S8 are turned on; when the driving signal of the switch tube S1, the switch tube S2, the switch tube S3 and the switch tube S6 is at a low level, the switch tube S1, the switch tube S2, the switch tube S3 and the switch tube S6 are turned off; at this time, the bridge arm output voltage V ab =V L ;

[0008] The second working mode: when the driving signal of the switch tube S2, the switch tube S4, the switch tube S7 and the switch tube S8 is at a high level, the switch tube S2, the switch tube S4, the switch tube S7 and the switch tube S8 are turned on; when the driving signal of the switch tube S1, the switch tube S3, the switch tube S5 and the switch tube S6 is at a low level, the switch tube S1, the switch tube S3, the switch tube S5 and the switch tube S6 are turned off; at this time, the bridge arm output voltage V ab =0;

[0009] The third working mode: when the switch tubes S5, S6, S7 and S8 are at a high level, the switch tubes S5, S6, S7 and S8 are turned on; when the driving signals of the switch tubes S1, S2, S3 and S4 are at a low level, the switch tubes S1, S2, S3 and S4 are turned off; at this time, the bridge arm output voltage V ab =0;

[0010] The fourth working mode: when the driving signal of the switch tube S1, the switch tube S4, the switch tube S5 and the switch tube S8 is at a high level, the switch tube S1, the switch tube S4, the switch tube S5 and the switch tube S8 are turned on; when the driving signal of the switch tube S2, the switch tube S3, the switch tube S6 and the switch tube S7 is at a low level, the switch tube S2, the switch tube S3, the switch tube S6 and the switch tube S7 are turned off; at this time, the bridge arm output voltage V ab =V H ;

[0011] The fifth working mode: when the driving signal of the switch tube S2, the switch tube S6, the switch tube S7 and the switch tube S8 is at a high level, the switch tube S2, the switch tube S6, the switch tube S7 and the switch tube S8 are turned on; when the driving signal of the switch tube S1, the switch tube S3, the switch tube S4 and the switch tube S5 is at a low level, the switch tube S1, the switch tube S3, the switch tube S4 and the switch tube S5 are turned off; at this time, the bridge arm output voltage V ab =-V L ;

[0012] The sixth working mode: when the driving signals of the switch tubes S2, S3, S6 and S7 are at a high level, the switch tubes S2, S3, S6 and S7 are turned on; when the driving signals of the switch tubes S1, S3, S4 and S5 are at a low level, the switch tubes S1, S3, S4 and S5 are turned off; at this time, the bridge arm output voltage V ab =-V H .

[0013] Due to the adoption of the above technical solution, the technical progress achieved by the present invention is:

[0014] 1. The high-reliability converter provided by the present invention has the characteristics of less passive components and no body diode reverse recovery problem of the power switch tube. At the same time, it can cope with the situation of single switch tube failure, simultaneous failure of two switch tubes and DC voltage source failure, has fault-tolerant operation capability, effectively improves the reliability of the converter, and has practical engineering application value;

[0015] 2. The control method of the high-reliability converter provided by the present invention can reduce the output inductor current ripple, improve the converter output overvoltage problem under open circuit fault, and is beneficial to improving the output voltage waveform quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a circuit topology diagram of the present invention;

[0017] Figure 2 This is the switch tube control logic generation diagram of the present invention. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with embodiments:

[0019] like Figure 1 As shown, a high reliability converter includes a high voltage DC source V H , low voltage DC source V L , switch tube S1 to switch tube S8, diode APD1 to diode APD8, diode SD1 to diode SD8 and filter inductor L o and capacitor C o ; The high voltage DC source V H The positive electrode is connected to the anode of diode SD1, the cathode of diode APD1, the anode of diode SD3, and the cathode of diode APD3 respectively; the high voltage DC source V H The negative electrode is connected to the low voltage DC source V L The negative electrode of the switch tube S2, the source electrode of the switch tube S4, the anode electrode of the diode APD4 are connected; the low voltage DC source V L The positive electrode of the diode APD7 is respectively connected to the source of the switch tube S7, the anode of the diode APD7, the source of the switch tube S8, and the anode of the diode APD8; the cathode of the diode APD7 is respectively connected to the anode of the diode SD7, the anode of the diode SD5, and the cathode of the diode APD5; the cathode of the diode APD8 is respectively connected to the anode of the diode SD8, the anode of the diode SD6, and the cathode of the diode APD6; the anode of the diode APD5 is respectively connected to the source of the switch tube S5, the source of the switch tube S1, the anode of the diode APD1, the anode of the diode SD2, the cathode of the diode APD2, and the filter inductor L o The anode of the diode APD6 is connected to the source of the switch tube S6, the source of the switch tube S3, the anode of the diode APD3, the anode of the diode SD4, the cathode of the diode APD4, and the capacitor C o and one end of the load; the filter inductor L o The output terminals are connected to capacitors C o the other end of the switch tube S1 is connected to the cathode of the diode SD1; the drain of the switch tube S2 is connected to the cathode of the diode SD2; the drain of the switch tube S3 is connected to the cathode of the diode SD3; the drain of the switch tube S4 is connected to the cathode of the diode SD4; the drain of the switch tube S5 is connected to the cathode of the diode SD5; the drain of the switch tube S6 is connected to the cathode of the diode SD6; the drain of the switch tube S7 is connected to the cathode of the diode SD7; the drain of the switch tube S8 is connected to the cathode of the diode SD8.

[0020] like Figure 2As shown, the drive signal of switch tube S1 is composed of the modulation wave V ref and the first carrier V cr1 After voltage comparison, V ref Greater than V cr1 When the output is high level, otherwise it outputs low level; the drive signal of the switch tube S5 is modulated by the wave V ref and the third carrier V cr3 After voltage comparison, V ref Greater than V cr3 When the output is high level, otherwise it outputs low level; the drive signal of the switch tube S4 is modulated by the modulation wave V ref and the fourth carrier V cr4 After voltage comparison, V ref Greater than V cr4 When the output is high level, otherwise it outputs low level; the drive signal of the switch tube S8 is modulated by the wave V ref and the second carrier V cr2 After voltage comparison, V ref Greater than V cr2 The output is high level when the switch is on, otherwise it outputs low level; the drive signals of the switch tube S1 and the switch tube S7 are complementary; the drive signals of the switch tube S2 and the switch tube S5 are complementary; the drive signals of the switch tube S4 and the switch tube S6 are complementary; the drive signals of the switch tube S3 and the switch tube S8 are complementary; the third carrier V cr3 With the fourth carrier V cr4 The two are generated in a phase shifting manner, with a phase difference of 180 degrees and the same waveform. The first carrier V cr1 With the second carrier V cr2 The waveforms are consistent, and are generated in a carrier stacking manner on the third carrier V cr3 The upper and fourth carrier V cr4 Below.

[0021] When the circuit of the present invention is working, six working modes are generated by controlling the on and off of the switch tubes S1 to S8, and five different levels are output. The specific control method is as follows:

[0022] The first working mode: when the driving signal of the switch tube S4, the switch tube S5, the switch tube S7 and the switch tube S8 is at a high level, the switch tube S4, the switch tube S5, the switch tube S7 and the switch tube S8 are turned on; when the driving signal of the switch tube S1, the switch tube S2, the switch tube S3 and the switch tube S6 is at a low level, the switch tube S1, the switch tube S2, the switch tube S3 and the switch tube S6 are turned off; at this time, the bridge arm output voltage V ab =V L ;

[0023] The second working mode: when the driving signal of the switch tube S2, the switch tube S4, the switch tube S7 and the switch tube S8 is at a high level, the switch tube S2, the switch tube S4, the switch tube S7 and the switch tube S8 are turned on; when the driving signal of the switch tube S1, the switch tube S3, the switch tube S5 and the switch tube S6 is at a low level, the switch tube S1, the switch tube S3, the switch tube S5 and the switch tube S6 are turned off; at this time, the bridge arm output voltage V ab =0;

[0024] The third working mode: when the switch tubes S5, S6, S7 and S8 are at a high level, the switch tubes S5, S6, S7 and S8 are turned on; when the driving signals of the switch tubes S1, S2, S3 and S4 are at a low level, the switch tubes S1, S2, S3 and S4 are turned off; at this time, the bridge arm output voltage V ab =0;

[0025] The fourth working mode: when the driving signal of the switch tube S1, the switch tube S4, the switch tube S5 and the switch tube S8 is at a high level, the switch tube S1, the switch tube S4, the switch tube S5 and the switch tube S8 are turned on; when the driving signal of the switch tube S2, the switch tube S3, the switch tube S6 and the switch tube S7 is at a low level, the switch tube S2, the switch tube S3, the switch tube S6 and the switch tube S7 are turned off; at this time, the bridge arm output voltage V ab =V H ;

[0026] The fifth working mode: when the driving signal of the switch tube S2, the switch tube S6, the switch tube S7 and the switch tube S8 is at a high level, the switch tube S2, the switch tube S6, the switch tube S7 and the switch tube S8 are turned on; when the driving signal of the switch tube S1, the switch tube S3, the switch tube S4 and the switch tube S5 is at a low level, the switch tube S1, the switch tube S3, the switch tube S4 and the switch tube S5 are turned off; at this time, the bridge arm output voltage V ab =-V L ;

[0027] The sixth working mode: when the driving signals of the switch tubes S2, S3, S6 and S7 are at a high level, the switch tubes S2, S3, S6 and S7 are turned on; when the driving signals of the switch tubes S1, S3, S4 and S5 are at a low level, the switch tubes S1, S3, S4 and S5 are turned off; at this time, the bridge arm output voltage V ab =-V H .

Claims

1. A high reliability converter, characterized in that: Including high voltage DC source V H , low voltage DC source V L , switch tube S1 to switch tube S8, diode APD1 to diode APD8, diode SD1 to diode SD8 and filter inductor L o and capacitor C o ; The high voltage DC source V H The positive electrode is connected to the anode of diode SD1, the cathode of diode APD1, the anode of diode SD3, and the cathode of diode APD3 respectively; the high voltage DC source V H The negative electrode is connected to the low voltage DC source V L The negative electrode of the switch tube S2, the source electrode of the switch tube S4, the anode electrode of the diode APD4 are connected; the low voltage DC source V L The positive electrode of the diode APD7 is respectively connected to the source of the switch tube S7, the anode of the diode APD7, the source of the switch tube S8, and the anode of the diode APD8; the cathode of the diode APD7 is respectively connected to the anode of the diode SD7, the anode of the diode SD5, and the cathode of the diode APD5; the cathode of the diode APD8 is respectively connected to the anode of the diode SD8, the anode of the diode SD6, and the cathode of the diode APD6; the anode of the diode APD5 is respectively connected to the source of the switch tube S5, the source of the switch tube S1, the anode of the diode APD1, the anode of the diode SD2, the cathode of the diode APD2, and the filter inductor L o The anode of the diode APD6 is connected to the source of the switch tube S6, the source of the switch tube S3, the anode of the diode APD3, the anode of the diode SD4, the cathode of the diode APD4, and the capacitor C o and one end of the load; the filter inductor L o The output terminals are connected to capacitors C o the other end of the switch tube S1 is connected to the cathode of the diode SD1; the drain of the switch tube S2 is connected to the cathode of the diode SD2; the drain of the switch tube S3 is connected to the cathode of the diode SD3; the drain of the switch tube S4 is connected to the cathode of the diode SD4; the drain of the switch tube S5 is connected to the cathode of the diode SD5; the drain of the switch tube S6 is connected to the cathode of the diode SD6; the drain of the switch tube S7 is connected to the cathode of the diode SD7; the drain of the switch tube S8 is connected to the cathode of the diode SD8.

2. A high reliability converter according to claim 1, characterized in that: The driving signal of the switch tube S1 is modulated by the wave V ref and the first carrier V cr1 After voltage comparison, V ref Greater than V cr1 When the output is high level, otherwise it outputs low level; the switch tube S5 driving signal is modulated by the wave V ref and the third carrier V cr3 After voltage comparison, V ref Greater than V cr3 When the output is high level, otherwise it outputs low level; the switch tube S4 driving signal is modulated by the wave V ref and the fourth carrier V cr4 After voltage comparison, V ref Greater than V cr4 When the output is high level, otherwise it outputs low level; the switch tube S8 driving signal is modulated by the wave V ref and the second carrier V cr2 After voltage comparison, V ref Greater than V cr2 The output is high level when the switch is on, otherwise it outputs low level; the switch tube S1 and the switch tube S7 drive signals are complementary; the switch tube S2 and the switch tube S5 drive signals are complementary; the switch tube S4 and the switch tube S6 drive signals are complementary; the switch tube S3 and the switch tube S8 drive signals are complementary; the third carrier V cr3 With the fourth carrier V cr4 The two are generated in a phase shifting manner, with a phase difference of 180 degrees and the same waveform. The first carrier V cr1 With the second carrier V cr2 The waveforms are consistent, and are generated in a carrier stacking manner on the third carrier V cr3 The upper and fourth carrier V cr4 Below.

3. A high-reliability converter control method, characterized in that: The high-reliability converter according to claim 1 is used to generate six working modes by controlling the on and off of the switch tubes S1 to S8, converting the DC voltage into an AC voltage output, and outputting five different levels. The specific control method is as follows: The first working mode: when the driving signal of the switch tube S4, the switch tube S5, the switch tube S7 and the switch tube S8 is at a high level, the switch tube S4, the switch tube S5, the switch tube S7 and the switch tube S8 are turned on; when the driving signal of the switch tube S1, the switch tube S2, the switch tube S3 and the switch tube S6 is at a low level, the switch tube S1, the switch tube S2, the switch tube S3 and the switch tube S6 are turned off; at this time, the bridge arm output voltage V ab =V L ; The second working mode: when the driving signal of the switch tube S2, the switch tube S4, the switch tube S7 and the switch tube S8 is at a high level, the switch tube S2, the switch tube S4, the switch tube S7 and the switch tube S8 are turned on; when the driving signal of the switch tube S1, the switch tube S3, the switch tube S5 and the switch tube S6 is at a low level, the switch tube S1, the switch tube S3, the switch tube S5 and the switch tube S6 are turned off; at this time, the bridge arm output voltage V ab =0; The third working mode: when the switch tubes S5, S6, S7 and S8 are at a high level, the switch tubes S5, S6, S7 and S8 are turned on; when the driving signals of the switch tubes S1, S2, S3 and S4 are at a low level, the switch tubes S1, S2, S3 and S4 are turned off; at this time, the bridge arm output voltage V ab =0; The fourth working mode: when the driving signal of the switch tube S1, the switch tube S4, the switch tube S5 and the switch tube S8 is at a high level, the switch tube S1, the switch tube S4, the switch tube S5 and the switch tube S8 are turned on; when the driving signal of the switch tube S2, the switch tube S3, the switch tube S6 and the switch tube S7 is at a low level, the switch tube S2, the switch tube S3, the switch tube S6 and the switch tube S7 are turned off; at this time, the bridge arm output voltage V ab =V H ; The fifth working mode: when the driving signal of the switch tube S2, the switch tube S6, the switch tube S7 and the switch tube S8 is at a high level, the switch tube S2, the switch tube S6, the switch tube S7 and the switch tube S8 are turned on; when the driving signal of the switch tube S1, the switch tube S3, the switch tube S4 and the switch tube S5 is at a low level, the switch tube S1, the switch tube S3, the switch tube S4 and the switch tube S5 are turned off; at this time, the bridge arm output voltage V ab =-V L ; The sixth working mode: when the driving signal of the switch tube S2, the switch tube S3, the switch tube S6 and the switch tube S7 is at a high level, the switch tube S2, the switch tube S3, the switch tube S6 and the switch tube S7 are turned on; when the driving signal of the switch tube S1, the switch tube S3, the switch tube S4 and the switch tube S5 is at a low level, the switch tube S1, the switch tube S3, the switch tube S4 and the switch tube S5 are turned off; at this time, the bridge arm output voltage V ab =-V H .

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