184 results about "Z source" patented technology

The invention discloses a stored energy type standard-Z source photovoltaic power generation control system and method. The control system comprises a controller and a stored energy type standard-Z source inverter, wherein the controller comprises a capacitor voltage outer ring and a stored energy battery current inner ring and is used for regulating the direct-connection duty ratio of the inverter, thus the voltage of a DC (direct-current) bus can be constant, although the photovoltaic cell voltage is changed in a wide range; and the output power of the inverter is controlled by a power ring, and the output power of photovoltaic cells and the inverter is controlled so as to carry out charge-discharge management on stored energy batteries, thus realizing maximum power tracking. According to the invention, single-stage power transform is used to complete boosting, reduction voltage, inversion and energy storage, so that a simpler structure is used to realize minimum inverter capacity, thus ensuring the voltage of the DC bus to be constant and a power grid to obtain stable power, thereby maximally collecting solar energy and improving generating efficiency.

The invention relates to a standard Z source three-level T-shaped inverter and an SVPWM method thereof. A topology has boost features identical to boost features of a standard Z source network three-level NPC inverter, however, few switching elements are utilized, and efficiency is high. Compared with a three-level T-shaped inverter, functions of boost and voltage reduction of the topology can be achieved, direct connection of an upper bridge arm and a lower bridge arm is allowed, reliability is improved remarkably, dead time is eliminated, and waveform distortion is prevented. Compared with a Z source three-level diode clamped inverter, current at an input end is continuous, ripple waves are small, and the input end does not need to be connected with a large-capacitance array set in parallel. Compared with a standard Z source two-level inverter, output voltage has neutral point electric potentials, therefore, high frequency harmonic waves are small, a required filter is small, a switching frequency can be reduced, and switching loss is less. The SVPWM method is adopted to control the inverter, so that switching frequencies are decreased, switching loss is reduced, and harmonic contents of the output voltage are reduced.

The present invention provides a z-source inverter and its soft starting method, belonging to power electronic converter. The inverter main circuit is composed of a DC voltage source, a three-phase inverter bridge, a z-source network, a power diode, characterized in that the positive end of the three-phase inverter bridge is connected to the cathode of the DC voltage source, the negative end of the three-phase inverter bridge is connected to the Z source network. Compared with the voltage source type and the current source type inverter, the Z source inverter realizes pressure raising change function, and the upper and the lower switch tubes of the same bridge arm are directly passing, so the dead zone does not need, the circuit structure is simple, having high credibility. Compared with the traditional Z source inverter, the capacitor voltage of the Z source network in the Z source inverter has small stress, and realizing the soft start of the transformer, avoiding the problems of large voltage and current when the traditional Z source inverter starts, the work of the transformer is safe and credible, and having light volume and weight.

The modulation methods for quasi-Z-source cascade multilevel inverters relate to control and signal modulation of quasi-Z-source cascade multilevel inverters, such as those used with photovoltaic power systems. The modulation methods for quasi-Z-source cascade multilevel inverters include a modular multilevel space vector modulation method for a photovoltaic quasi-Z-source cascade multilevel inverter for compensating for unequal voltages of separate photovoltaic modules, a pulse-width-amplitude modulation method for multilevel inverters for use in solar panel arrays attached to a three phase power grid, and a grid-connected control method for quasi-Z-source cascade multilevel inverter-based photovoltaic power generation for extracting maximum power from each Z-source cascade multilevel inverter.

The invention relates to a control method for a bidirectional quasi-Z-source inversion type motor driving system. The control method comprises the following steps of collecting the voltage of a capacitor C2 and the current of a permanent magnet synchronous motor; obtaining voltage components of a d axis and a q axis; obtaining a direct-connection duty ratio; carrying out an SVPWM (space vector pulse width modulation) algorithm by inserting the direct-connection duty ratio according to the voltage components of the d axis and the q axis and the direct-through duty ratio to obtain six paths of PWM control signals for controlling the on and off of three-phase bridge arms of a three-phase bridge type inverter; and carrying out logic calculation on the six paths of PWM control signals to output a PWM control signal for controlling the on and off of an IGBT switch tube S7. Compared with the prior art, the average direct-connection duty ratio and the capacitor voltage closed loop control closed loop policy are added to the conventional SVPWM control method, so that the direct current side voltage has the voltage boosting capability; and on the basis, the power switch S7 which is complementary with the direct-connection state is further designed, so that the bidirectional flow of energy can be realized.

The invention relates to a wind and solar hybrid generating system based on a Z source, belonging to the field of new energy generation and aiming to provide users with a safe and stable power sourceby utilizing wind energy and solar energy common in nature. The invention adopts a pressure-boosting device based on a Z source circuit structure and a tracking control strategy based on DSP to achieve a variable-step perturbation observation method. The wind and solar hybrid generating system based on the Z source comprises a charging and discharging controller, an energy-storing accumulator andan inventor. A wind and solar hybrid controller converts wind energy captured by a wind-driven generator into a direct current by utilizing a rectifier; and the energy-storing device (accumulator) ischarged by the direct current and solar energy captured by a solar panel; the inventor releases electric energy stored in the accumulator and stably outputs an alternating voltage of 220V by a certaincircuit and a control method to provide for load use. The system has simple structure and less hardware and effectively improves the working efficiency.

The invention relates to a Z-Source full-bridge converter for soft-switching PFC. The Z-Source full-bridge converter comprises a rectifier bridge (Q1), a full-bridge inverter (Q2) and a transformer (T), and is characterized in that an impedance network (Z) is also included; and the impedance network (Z) is connected in parallel between the rectifier bridge (Q1) and two inverter bridge legs of the full-bridge inverter (Q2). The existence of the impedance network (Z) avoids the damage caused by the direct connection between the two inverter bridge legs of the full-bridge inverter (Q2). When an upper bridge leg and a lower bridge leg of the full-bridge inverter (Q2) are directly connected with each other, the impedance network (Z) and the full-bridge inverter (Q2) form a voltage booster circuit, and correction of the input power factor can be realized through controlling the direct connection time of the upper bridge leg and the lower bridge leg. The Z-Source full-bridge converter forms a primary voltage booster circuit through the impedance network (Z) and the full-bridge inverter (Q2), and enhances the output voltage very easily through the secondary booster of the transformer (T), thereby being very suitable for an ozonizer power supply required to output high pressure.

The invention provides a current continuous high-gain switch voltage rise quasi-Z-source converter circuit. The circuit comprises a power supply; a two-port switch voltage rise unit composed of a first inductor, a first diode, a first power switch tube, a first capacitor and a second diode; a quasi-Z-source network composed of a second inductor, a second capacitor, a third capacitor and a third diode; a second power switch tube; a fourth diode; an output capacitor; and a load. The whole circuit is simple in structure; the single-level voltage rise and reduction features of the switch voltage rise unit and the quasi-Z-source network are combined; the higher output voltage gain is realized; the current of the power supply is continuous; the current of the load is continuous; the output and input are in zero potential; there is no start surge current in the circuit; and there is no surge current at the moment when the switch tube is switched on.

The invention discloses an improved Z-source boosting DC (direct current)-DC converter, comprising a voltage source, a Z-source impedance network, an MOS (metal oxide semiconductor) tube, a second diode, an output filter capacitor and a load; the Z-source impedance network is formed by a first inductor, a second inductor, a first capacitor, a second capacitor and a first diode. The voltage source Vs, the Z-source impedance network and the MOS tube form a boosting circuit; the second diode, the output filter capacitor and the load form an output circuit. The improved Z-source boosting DC-DC converter is simple in integral circuit structure and has higher output voltage gain, the capacitance and voltage stress of the Z-source impedance network is low, and the circuit has no starting impact problem.

The invention provides an intrinsic safety output quasi-Z-source switching converter which comprises a Buck type DC/DC switching conversion circuit, a quasi-Z-source filter network and a safety barrier protection circuit which are connected in sequence; the quasi-Z-source filter network comprises an LC filter composed of an inductor and a capacitor, another inductor, another capacitor and a diode, wherein the diode is connected in series between the first inductor and the first capacitor, the second inductor is connected to the output end of the first capacitor, and the second capacitor is connected in parallel to two ends of the diode and the second inductor which are connected in series; the input end of the LC filter is the input end of the quasi-Z-source filter network; and the connecting end between the other inductor and the other capacitor is the output end of the quasi-Z-source filter network. The intrinsic safety output quasi-Z-source switching converter has the advantages that the energy releasing speed of a circuit is decreased through the quasi-Z-source filter network so as to be matched with the safety barrier protection speed, and the energy of sparks output by the circuit during failures can be further reduced, so that the capacity of an intrinsic safety power supply is improved; the circuit structure is simple, and the reliability is high; and the advantages of the invention are incomparable with those of the traditional technology.

The invention discloses a Z source DC- DC convert includes a switch module, a first diode, a second diode, a third diode, a first inductor, a second inductor, a first capacitor, a second capacitor, athird capacitor, and a fourth capacitor. As can be seen, the Z source DC-DC converter gain can achieve high gain at low duty cycle. While the cascade is not needed to realize high gain, and the complexity and cost of the circuit structure are reduced; In addition, the on-loss of the switching transistor is reduced, and the Z-source DC-DC converter efficiency; And there is only one switch modulein the Z source DC -DC converter , which is easy to control. The invention also provides a new energy source system, which comprises a Z-source DC- DC convert has that same beneficial effect.

The invention provides a switched inductance quasi-Z source DC-DC converter circuit which comprises a voltage source, a first inductor, a first diode, a first capacitor, a switched inductance impedance network, a second capacitor, a switching tube, a fourth inductor, an output capacitor and a load, wherein the switched inductance impedance network consists of a second inductor, a third inductor, a second diode, a third diode and a fourth diode. According to the switched inductance quasi-Z source DC-DC converter circuit, the voltage source, the first inductor, the first capacitor and the switching tube are sequentially connected in series to form a first-stage booster circuit; the second capacitor, the switched inductance impedance network and the switching tube are sequentially connected in series to form a second-stage booster circuit; the fourth inductor, the output capacitor and the load form an output circuit; the whole circuit is simple in structure and free of starting impulse current and transient impulse current generated by the turning on of the switching tube, and has higher output voltage gain and lower capacitance voltage stress, only one switching tube is adopted, power current and load current are both continuous, and common ground for input and output is ensured.

The invention relates to the technical field of welding power sources, and in particular relates to a novel Z source welding power source system. The novel Z source welding power source system comprises a main circuit, a power supply main control and man-machine interface board and an IGBT (insulated gate bipolar transistor) driving circuit, wherein the IGBT driving circuit is respectively connected with the main circuit and the power supply main control and man-machine interface board, and the main circuit comprises a Z source network. The invention has the beneficial effects that the influence of dead zone effect to an inverter can be eliminated, the resistance of a welding machine to EMI (electromagnetic interference) noise can be enhanced, and the welding machine can not be damaged owning to false triggering of an inverter bridge leg.

The invention discloses an enhanced and high-performance Z-source inverter. The enhanced and high-performance Z-source inverter comprises a DC power supply V0, a diode D7, an input capacitor C3, a switch tube SW7 and a three-phase inverter, also comprises a Z-source network and is characterized in that the Z-source network comprises a switch inductor, a diode, an inductor and a capacitor, a singleinductor of a traditional Z-source network is substituted by the switch inductor, the Z-source network is connected in series between the power diode SW7 and the three-phase inversion bridge, a positive electrode of the diode D7 is connected with a positive electrode of the DC power supply V0, a positive electrode of the power diode SW7 is connected with a negative electrode of the diode D7 and one end of the capacitor C3, and the other pole of the capacitor C3 is connected with a negative electrode of the DC power supply V0 and the Z-source network. Compared with a traditional Z-source inverter, the enhanced and high-performance Z-source inverter has the advantages that DC chain voltage distortion caused by relatively small inductance value of the Z-source network or a light-load mode can be eliminated, so that the abnormal working state of the traditional Z-source inverter is eliminated; the adaptive capacity of a load is high, and large-range change of the load can be adapted; theboost capability of the inverter can be remarkably improved, high modulation factor is achieved, and the output quality of the whole inverter is improved; and meanwhile, the capacitance voltage stressof the Z-source network is effectively reduced, so that the volume and the weight of the inverter are reduced.

The invention provides a Z-source half-bridge inverter, comprising a DC voltage source and a half-bridge inverter which consists of two stored energy capacitors and two switch tubes; the Z-source half-bridge inverter also comprises a diode (D) and a Z-source impedance; the Z-source impedance is connected in parallel between the two inverter bridge arms of the half-bridge inverter and two ends of the DC voltage source; the diode (D) is used for blocking the current of the Z-source impedance from flowing back in the voltage source. The Z-source impedance avoids the damage due to the direct conduction of a first switch tube and a second switch tube; and the first switch tube and the second switch tube have a boost function when being conducted simultaneously. The duty cycle of the first switch and the second switch tube can be controlled to realize the buck or boost of the inverter, thus realizing the output of symmetric or asymmetric amplitude of positive and negative pulse waveform. The Z-source half-bridge inverter has high reliability, wide output voltage range and abundant output AC pulse waveform, and is especially suitable for electrochemical power devices such as electroanalysis devices and electroplating devices.

The invention relates to a battery energy-storage power conversion system containing a Z source network and a control method for the system. The power conversion system comprises a lithium battery system, the Z source network, a two-way DC/AC (direct current/alternating current) converter, a filter circuit and a DSP (digital signal processor) chip, wherein the lithium battery system, the Z source network, the two-way DC/AC converter and the filter circuit are connected with one another in sequence. The control method comprises the following steps: the DSP chip monitors the lithium battery system timely and controls the charging and the discharging for the DSP chip; the DSP chip monitors the Z source network; and the DSP chip monitors the two-way DC/AC converter. The scheme in the invention can overcome the defects of the existing power conversion system that the equipment is complicated, the two-way power conversion efficiency is low, the protection of an energy-storage battery system is absent, the allowable fluctuation range of the direct-current chain voltage is small, an inverter bridge arm switch tube can not be connected directly, the grid-connected harmonic filter effect is poor, etc.

The invention discloses a method for eliminating harmonic wave in a Z-source alternating current (AC)/AC converter by using pulse-width modulation (PWM), and belongs to the field of signal processing method. The method comprises the following steps of: extracting fundamental wave amount of input voltage through lowpass filtering; and generating a modulation function of which the duty cycle varies along with time through open-loop control by using an error signal which is generated by comparing a fundamental wave amount and an overall amount of an input voltage in real time and by adopting a non-constant duty cycle control mode. The modulation function controls breakover of two groups of serial four-quadrant switches and regulates output of load voltage, and restrains low subharmonic voltage of the input voltage, and moreover, a duty cycle value can be slightly regulated in real time through the output voltage control step to stabilize the output voltage. By the method, only the simple lowpass filtering and sampling and the feed-forward open-loop control are required, and the requirement of the system for controller band width is obviously reduced; and the method is strong in stability and reliability, and the adaptive capacity to emergency harmonic distortion at an alternating current system side is improved.

The invention discloses a fuel cell wide-range input type quasi-Z-source switch capacitor boost-type DC converter. The DC converter is based on a quasi-Z-source network and a switch capacitor network. The power input end of the DC converter is connected with a fuel cell, which is embodied by connecting the power input end Uin with a diode D1 capable of preventing current reversal in series; the front stage is the quasi-Z-source network, which is formed by an inductor L1, a diode D2, an inductor L2, a capacitor C1 and a capacitor C2; the back stage is the switch capacitor network, which is formed by a capacitor C3, a capacitor C4, a capacitor C5, a diode D3, a diode D4 and a diode D5; and an output end is connected with a high-voltage DC bus. The DC converter improves topology boosting capability and reduces voltage stress born by a power device, and is more suitable for voltage conversion occasions of the fuel cell.