37results about How to "Eliminate higher harmonics" patented technology

The invention relates to a battery energy storage system based power conversion system and a control method thereof. The power conversion system comprises a battery energy storage system, a bidirectional DC / DC (direct-current) converter, a grid-side current transformer, a filter circuit and an isolated voltage transformer. The battery energy storage system is in parallel connection with a direct-current bus of the grid-side current transformer through the bidirectional DC / DC converter; the grid-side current transformer, the filter circuit and the isolated voltage transformer are connected in sequence; and the isolated voltage transformer accesses to a power grid. The control method includes sequentially monitoring the battery energy storage system, the bidirectional DC / DC converter, the grid-side current transformer, the filter circuit and the isolated voltage transformer by a control circuit. Since the battery energy storage system utilizes battery cells connected in series and is in parallel connection with the common direct-current bus through the bidirectional DC / DC converter, circulation among battery packs is avoided, and capacity expansion of the system is facilitated. Further, by the aid of the monitoring control strategy for SOC (super capacitor state of charge) of the battery energy storage system and battery end voltage, excessive charge or discharge state of the battery energy storage system is avoided, service lives of the battery packs are prolonged, and comprehensive service cost is lowered.

The invention discloses an anti-interference method of a power supply circuit of a PLC (Programmable Logic Controller) of an internal mixer. The anti-interference method comprises the steps of reducing the voltage of the 380 V AC (Alternating Current) into a 220 V AC through a circuit breaker and a transformer in an isolated manner; and rectifying the 220 V AC into a 24V DC through a switching power supply. The anti-interference method is characterized in that a double T-type LC loss-pass filtering circuit is connected between the secondary side of the transformer and the input end of the switching power supply; the double T-type LC loss-pass filtering circuit comprises a C1 connected in parallel with the secondary side of the transformer and a C2 connected in parallel with the input end of the switching power supply; one end of an L1 and an L2 after being connected in series is connected with the C1 while the other end thereof is connected with the C2; one end of an L3 and an L4 after connected in series is connected with the other end of the C1 while the other end thereof is connected with the other end of the C2; a resistor R1 is connected between the connecting end of the L1 and the L2 and the connecting end of the L3 and the L4. As a method of connecting a double T-type LC low-pass filter and a ring-type iron core transformer in series is adopted at the power input end of the PLC, interference from electromagnetic interference and spark interference which are generated by connection and disconnection of high-order harmonics, an electromagnetic valve, a motor and a contactor of a high-voltage frequency converter to the PLC is removed, and good use effect is obtained; and the anti-interference method is applied to a control system of a high-voltage main motor for driving the internal mixer and control systems of engineering and mining equipment in other industries.

The invention relates to a skewed rotor core which comprises a rotating shaft and a skewed rotor core, wherein the skewed core consists of two or more than two one-way skewed cores; the two adjacent one-way skewed cores have different inclined directions; an inflection point is formed at the intersection of adjacent two skewed slots; and the one-way skewed cores is formed by laminating rotor sheets. By adoption of a connecting key groove through which the one-way skewed rotor core in each skewed section is laminated and correspondingly the one-way skewed rotor core in a skewed section is generally processed, each rotor sheet can be directly punched on a common punch press, so that the processing period and cost are greatly reduced. The invention relates to a motor comprising the skewed rotor core, and a method for manufacturing the skewed rotor core.

The invention discloses a filter protection circuit of a household appliance. The filter protection circuit is arranged in the electrical control system of the household appliance and connected between a single-chip microcomputer of the electrical control system and a signal detection circuit; The inductance coil and the resistor between the signal detection circuit, the voltage regulator tube connected between one end of the inductance coil and the ground, and the first capacitor connected between the other end of the inductance coil and the ground. Preferably, a second capacitor connected in parallel to both ends of the voltage regulator tube is further included, that is, the voltage regulator tube and the π-shaped filter are connected in parallel. Wherein, the inductance coil is a PFC inductance coil. The invention can be widely used in household appliances such as AC frequency conversion washing machines, refrigerators or air conditioners, and can reduce the interference to detection circuits and single-chip microcomputers. When overcurrent, overvoltage or high temperature occurs, the safety of the inverter circuit can be guaranteed through the single-chip microcomputer. .