5 results about "Power electronics" patented technology

The invention relates to a converse-solution PWM (Pulse-Width Modulation) inverter and a control method, and belongs to the fields of power electronics, electric drive and electrical power systems. The inverter comprises a main circuit unit, a drive and power amplifier unit, a PWM module, an AD sampling module, a DSP (Digital Signal Processor), a serial port communication module, a display unit, a direct current voltage detection circuit and a direct current voltage conditioning circuit; and the inverter further comprises a voltage current detection and conditioning circuit and a power grid phase A voltage zero crossing detection and conditioning circuit. According to the inverter, the problems that a load is unbalanced and the middle of DC side voltage cannot be found are not considered, and only needed line voltage needs to be obtained; even under the condition of unbalanced load, adjustment can be carried out by using a control policy, and at the moment, the line voltage is adjusted, so no mutual interference exists; and the line voltage can be adjusted to a balanced state, and the requirement that in a practical system the line voltage output by the inverter is sine wave can be met.

The invention discloses an input surge current suppression circuit and method of a capacitor, and relates to the technical field of power electronics. The input surge current suppression circuit comprises a variable resistance circuit, a detection control unit is arranged for the conduction internal resistor of a field effect transistor Q1 in the variable resistance circuit, the detection control unit is used for detecting the flowing surge current, and when the surge current is greater than a set value, the variable resistance circuit is immediately recovered to high resistance, so that the energy storage capacitor branch is cut off from the load of the input power supply, and the input surge current is suppressed. The input surge current suppression circuit is simple, low in cost, good in power-on surge current suppression effect and high in universality.

The invention discloses a position sensorless control method, device and system for a permanent magnet synchronous motor with an LC filter, and the method comprises the steps: obtaining the observation values of the alpha-axis component and the beta-axis component of the stator voltage of the permanent magnet synchronous motor in the kth sampling period according to the alpha-axis component and the beta-axis component of the inverter side voltage in the (k-1) th sampling period and the (k-2) th sampling period; obtaining the stator current of the permanent magnet synchronous motor according to the inverter side current and the LC filter capacitor fundamental wave current; observation values of alpha-axis and beta-axis components of stator voltage of the permanent magnet synchronous motor and stator current of the permanent magnet synchronous motor in the kth sampling period are calculated, and an estimated value of extended counter electromotive force of the permanent magnet synchronous motor is observed; and according to the estimated value of the extended counter electromotive force of the permanent magnet synchronous motor, obtaining the estimated electrical angular velocity and electrical angle of the permanent magnet synchronous motor. According to the invention, the long-line effect influence caused by high frequency of power electronics is effectively solved through the LC filter, position-sensorless control can be realized, the cost of the control system is effectively reduced, and the reliability of the system is improved.

The invention discloses a forward feedback type absorption circuit for improving the efficiency of a direct-current solid-state circuit breaker, and relates to the technical field of power electronics. The circuit comprises a voltage spike absorption circuit, a forward energy storage circuit, a reverse energy storage circuit and an energy feedback circuit, wherein the voltage spike absorption circuit, the forward energy storage circuit and the reverse energy storage circuit are respectively connected in parallel at two ends of a first main power tube and a second main power tube which are connected in series reversely, and the energy feedback circuit is connected in parallel at two ends of a power supply. The first end of the first main power tube and the second end of the second main power tube are respectively connected with two ends of a power supply. One end of the load is connected with the second end of the second main power tube, the other end of the load is connected with the negative electrode of the power supply, the voltage spike absorption circuit is used for absorbing voltage spikes, the forward energy storage circuit and the reverse energy storage circuit are used for storing energy when the load is short-circuited, and the energy feedback circuit is used for feeding back the stored energy to the power supply. The circuit enables energy to be fed back to a power supply while providing a voltage spike absorption function, and improves the efficiency of the DC solid-state circuit breaker.